Atlas Of Radiology Of The Traumatized Dog And Cat The Case-Based Approach

Joe P. Morgan · Pim Wolvekamp
Atlas of Radiology of the
Traumatized Dog and Cat
The Case-Based Approach

Joe P. Morgan · Pim Wolvekamp
Atlas of Radiology of the
Traumatized Dog and Cat
Second Edition
The Case-Based Approach

Joe P. Morgan, DVM, Vet. med. dr.
School of Veterinary Medicine
University of California
Davis, United States of America
Pim Wolvekamp, DVM, PhD
Faculty of Veterinary Medicine
University of Utrecht
Utrecht, The Netherlands
© 2004, Schlütersche Verlagsgesellschaft mbH & Co. KG, Hans-Böckler-Allee 7, 30173 Hannover
E-mail: info@schluetersche.de
Printed in Germany
ISBN 3-89993-008-8
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this textbook. In many cases controlled research concerning the use of a given drug in animals is lacking. This book makes no
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IV

Preface . . . . . . . . . . . . . . . . . . . . . . . . . VII
Notice . . . . . . . . . . . . . . . . . . . . . . . . . .VIII
1 Introduction . . . . . . . . . . . . . . . . . . . . 1
1.1 Characteristics of a diagnostic
radiographic study . . . . . . . . . . . . . . . . . 2
1.2 Importance of radiographic quality . . . . 3
1.3 Use of correct radiographic
technique . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.4 Use of a grid technique . . . . . . . . . . . . . 4
1.5 Selection of intensifying screens . . . . . . . 4
1.6 Radiographic viewing . . . . . . . . . . . . . . . 4
1.7 Radiographic contrast . . . . . . . . . . . . . . . 5
1.8 Film density versus tissue density . . . . . 5
1.9 More about “density”? . . . . . . . . . . . . . . 5
1.10 The art of radiographic evaluation . . . . 6
1.11 Methods of radiographic evaluation . . . 6
1.12 Preparing the radiological report . . . . . . 6
1.13 Terms to understand in radiology . . . . . 7
2 Radiology of Thoracic Trauma
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . 10
2.1.1 Value of thoracic radiology . . . . . . . . . . . . . 10
2.1.2 Indications for thoracic radiology . . . . . . . . . 10
2.1.3 Patient positioning . . . . . . . . . . . . . . . . . . . 10
2.1.4 Radiographic evaluation of
thoracic studies . . . . . . . . . . . . . . . . . . . . . 10
2.1.5 Radiographic features in thoracic trauma . . . 12
2.1.5.1 Disruption of the thoracic wall . . . . . . . . . . 12
2.1.5.2 Pleural space . . . . . . . . . . . . . . . . . . . . . . . . 12
2.1.5.3 Pneumothorax . . . . . . . . . . . . . . . . . . . . . . 12
2.1.5.4 Pleural fluid . . . . . . . . . . . . . . . . . . . . . . . . 14
2.1.5.5 Diaphragmatic rupture . . . . . . . . . . . . . . . . 14
2.1.5.6 Damage to lung parenchyma . . . . . . . . . . . . 15
2.1.5.7 Mediastinal injury . . . . . . . . . . . . . . . . . . . . 18
2.1.5.8 The heart . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.1.5.9 The esophagus . . . . . . . . . . . . . . . . . . . . . . 19
2.2 Case presentations . . . . . . . . . . . . . . . . . . 19
2.2.1 Thorax wall injury . . . . . . . . . . . . . . . . . . . 20
2.2.2 Paracostal hernia . . . . . . . . . . . . . . . . . . . . . 46
2.2.3 Pleural fluid . . . . . . . . . . . . . . . . . . . . . . . . 52
2.2.4 Lung injury . . . . . . . . . . . . . . . . . . . . . . . . 64
2.2.5 Pulmonary hematoma . . . . . . . . . . . . . . . . . 86
2.2.6 Interstitial nodules . . . . . . . . . . . . . . . . . . . . 89
2.2.7 Diaphragmatic hernia . . . . . . . . . . . . . . . . . 91
2.2.8 Pleural air . . . . . . . . . . . . . . . . . . . . . . . . . . 108
2.2.9 Tension pneumothorax . . . . . . . . . . . . . . . . 123
2.2.10 Pneumomediastinum . . . . . . . . . . . . . . . . . . 130
2.2.11 Hemomediastinum . . . . . . . . . . . . . . . . . . . 138
2.2.12 Iatrogenic injury . . . . . . . . . . . . . . . . . . . . . 142
2.2.13 Tracheal/bronchial foreign bodies . . . . . . . . 165
2.2.14 Tracheal injury . . . . . . . . . . . . . . . . . . . . . . 178
2.2.15 Esophageal foreign bodies . . . . . . . . . . . . . . 180
2.2.16 Esophageal injury . . . . . . . . . . . . . . . . . . . . 188
3 Radiology of Abdominal Trauma
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . 198
3.1.1 The value of abdominal radiology . . . . . . . . 198
3.1.2 Indications for abdominal radiology . . . . . . . 198
abdominal radiographs . . . . . . . . . . . . . . . . . 198
3.1.4 Radiographic features in
abdominal trauma . . . . . . . . . . . . . . . . . . . . 199
3.1.4.1 Peripheral soft tissue trauma . . . . . . . . . . . . . 200
3.1.4.2 Fractures . . . . . . . . . . . . . . . . . . . . . . . . . . 200
3.1.4.3 Peritoneal fluid . . . . . . . . . . . . . . . . . . . . . . 200
3.1.4.4 Peritoneal air . . . . . . . . . . . . . . . . . . . . . . . 201
3.1.4.5 Retroperitoneal fluid . . . . . . . . . . . . . . . . . 201
3.1.4.6 Retroperitoneal air . . . . . . . . . . . . . . . . . . . 202
3.1.4.7 Organ enlargement . . . . . . . . . . . . . . . . . . . 202
3.1.4.8 The pelvis . . . . . . . . . . . . . . . . . . . . . . . . . 202
3.1.5 Use of contrast studies in the
traumatized abdomen . . . . . . . . . . . . . . . . . 202
3.1.5.1 Urinary tract trauma . . . . . . . . . . . . . . . . . . 202
3.1.5.2 Gastrointestinal tract trauma . . . . . . . . . . . . 203
Gastric foreign bodies . . . . . . . . . . . . . . . . . 203
3.2.1 Gastric foreign bodies and dilatation . . . . . . . 204
3.2.2 Small bowel foreign bodies . . . . . . . . . . . . . 208
3.2.3 Peritoneal fluid . . . . . . . . . . . . . . . . . . . . . . 215
3.2.4 Inguinal hernias . . . . . . . . . . . . . . . . . . . . . 220
3.2.5 Renal, ureteral, and urinary
bladder injury . . . . . . . . . . . . . . . . . . . . . . . 230
3.2.6 Urethral injury . . . . . . . . . . . . . . . . . . . . . . 246
3.2.8 Postsurgical problems . . . . . . . . . . . . . . . . . 266
4 Radiology of Musculoskeletal
Trauma and Emergency Cases
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . 270
4.1.1 The order of case presentation . . . . . . . . . . . 272
4.1.2 Type of information gained by a
radiographic evaluation of the skeleton
in the trauma patient . . . . . . . . . . . . . . . . . . 272
V
Contents

4.1.3 Indications for radiography in suspected
musculoskeletal trauma . . . . . . . . . . . . . . . . 273
4.1.4 Factors influencing radiographic
image quality . . . . . . . . . . . . . . . . . . . . . . . 273
4.1.5 Enhancement of the diagnostic
quality of a musculoskeletal . . . . . . . . . . . . . 274
4.1.6 Use of sequential radiographic studies . . . . . . 275
4.2.1 Radiographic features of
appendicular skeletal injury . . . . . . . . . . . . . 276
4.2.1.1 Fracture classification . . . . . . . . . . . . . . . . . 276
4.2.1.2 Orthopedic fixation devices . . . . . . . . . . . . 276
4.2.1.3 Post-traumatic aseptic necrosis . . . . . . . . . . . 277
4.2.1.4 Disuse osteoporosis (osteopenia) . . . . . . . . . . 277
4.2.1.5 Forelimb injury . . . . . . . . . . . . . . . . . . . . . . 277
Scapula and shoulder joint . . . . . . . . . . . . . . 277
Humerus and elbow joint . . . . . . . . . . . . . . 289
Radius and ulna . . . . . . . . . . . . . . . . . . . . . 294
Forefoot . . . . . . . . . . . . . . . . . . . . . . . . . . . 302
4.2.1.6 Pelvic limb injury . . . . . . . . . . . . . . . . . . . . 319
Pelvis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 319
Hip Joint . . . . . . . . . . . . . . . . . . . . . . . . . . 340
Femur . . . . . . . . . . . . . . . . . . . . . . . . . . . . 360
Stifle joint . . . . . . . . . . . . . . . . . . . . . . . . . 365
Tibia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369
Hindfoot . . . . . . . . . . . . . . . . . . . . . . . . . . 382
4.2.2 Radiographic features of axial
skeleton injuries . . . . . . . . . . . . . . . . . . . . . 387
4.2.2.1 Disruption of the thoracic wall . . . . . . . . . . 388
4.2.2.2 Head . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 392
4.2.2.3 Spine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395
Cervical vertebrae . . . . . . . . . . . . . . . . . . . . 396
Thoracic vertebrae . . . . . . . . . . . . . . . . . . . 398
Lumbar vertebrae . . . . . . . . . . . . . . . . . . . . 408
4.2.2.4 Malunion fractures . . . . . . . . . . . . . . . . . . . 418
4.2.2.5 Non-union or delayed union fractures . . . . . 440
4.2.2.6 Traumatic injuries to growing bones . . . . . . 448
Physeal growth injuries . . . . . . . . . . . . . . . . 448
Apophyseal fractures . . . . . . . . . . . . . . . . . . 466
4.2.2.7 Radiographic changes of osteomyelitis . . . . . 470
5 Radiographic Features of
Soft Tissue Injuries
5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . 487
6 Radiographic Features of
Gunshot Injuries
6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . 492
7 Radiographic Features in Cases of
Abuse
7.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . 523
8 Poisoning
8.1.1 Rodenticide poisoning . . . . . . . . . . . . . . . . 539
8.1.2 Herbicide poisoning . . . . . . . . . . . . . . . . . . 552
VI

VII
This book has been written in particular for the clinician faced
with the diagnostic and treatment problems associated of deal-
ing with trauma patients. The authors at the start in writing
made a basic decision to direct the case presentation towards
the preponderant use of diagnostic radiology. This not only
includes the classical use of radiology for assessing bony struc-
tures, but also the use of diagnostic radiology for the evalua-
tion of thoracic and abdominal trauma. When radiography of
the thorax is necessary, it is easy for the clinician to make ab-
dominal radiographs too, with minimal trauma to the patient
and this procedure can result in a quick evaluation of the clin-
ical status of the patient in which a physical examination may
be limited at the best. Many of the abdominal lesions depict-
ed could have been easily diagnosed using ultrasound; howev-
er, we have directed the case discussion toward the use of di-
agnostic radiology because we thought it the better of the two
techniques for determining the status of the patient as quickly
as possible, meaning that treatment can be instituted more
quickly. Also the use of an ultrasound probe in a potentially
traumatized abdomen can be associated with some risk. In ad-
dition, the efficient use of ultrasound, endoscopy, and la-
paroscopy is very operator dependent making some clinicians
argue strongly for their use, while others are less skillful and
not as anxious. Radiographs tend to be evaluated more accu-
rately by a larger percentage of those in veterinary practice to-
day.
Where possible the treatment given to each case is reported,
though the treatments used in these cases may not match that
which might have been recommended by many of our read-
ers. Unfortunately, the hospital records often do not include
the details of why a certain decision was made. Frequently, a
particular decision was based on purely financial considera-
tions. In some patients no treatment is reported as they were
not treated at our clinic. This may have been simply due to the
owner’s desire to return to a clinic that was closer to home. In
other cases, the reason a patient left the hospital prior to treat-
ment is often not clearly stated in the records.
In some of the patients presented, the case history leaves little
doubt that they had possibly been mismanaged. Again, the rea-
sons for any delay in surgical or other treatment are often not
described in the records, and indeed there may have even been
a very sound reason for the delay.
The preponderance of cases featured in this book are feline.
This bias is not intended to give the impression that dogs are
less effected by traumatic incidences, but is only a reflection
of the fact that the examination of smaller patients usually pro-
duces radiographs of higher quality permitting the features or
patterns of a particular disease to be more easily reproduced in
print.
Despite this bias, we hope our selection of trauma cases may
provide you with enjoyment in following in the examination
and determination of a diagnosis. The book in the hands of a
student hopefully will provide them with an opportunity of
exploring some of the methods of evaluation of trauma and
emergency patients and to learn that not all traumas are asso-
ciated with a grave prognosis. The body is really quite resilient
and can withstand not only the original trauma, but also diag-
nostic techniques and even misguided treatment.
Preface
Summer 2004 The Authors

Notice
As the detailed descriptions of the radiographs are given in the
text of the case studies, either no or only simplified headings
are given. Where necessary, grey oblongs have been drawn as
pictograms next to a particular heading to show which pic-
tures belong to it.
VIII

Trauma is defined as a suddenly applied physical force that re-
sults in anatomic and physiologic alterations. The injury varies
with the amount of force applied, the means by which it is ap-
plied, and the anatomic organs affected (Table 1.1). The event
can be focal or generalized, affecting a single organ or a number
of organs. Trauma can result in a patient with apparently mini-
mal injury, a patient who is paralyzed, or a patient who is in se-
vere shock. The patient may be presented immediately follow-
ingthetraumaorpresentationmaybedelayedbecauseoftheab-
sence of the animal or because of the hesitancy of the owners.
Most trauma cases in veterinary practise are due to accidents
in which the patient is struck by a moving object such as a car,
bus, truck, or bicycle. The nature of the injury varies depend-
ing on whether the patient is thrown free, crushed by a part
of the vehicle passing over it, or is dragged by the vehicle.
Other types of trauma result from the patient falling, with the
injury depending on the distance of the fall and the nature of
the landing. Dogs jumping from the back of a moving vehicle
involve falling only a short distance, but the trauma of hitting
the road at a high speed results in severe injury to both bone
and soft tissues. Other possibilities of trauma occur when the
patient has been hit by a falling object, or is kicked or struck
by something. Bite wounds are another type of trauma that
constitute a frequent cause of injury in both small and large
patients, and can be complicated by secondary infection. Pen-
etrating injuries are a separate classification of injury and can
be due to many types of projectiles. Gunshots are a common
cause of injury in certain societies (Chap. 6). Abuse is a spe-
cific classification of trauma and should be suspected in cer-
tain type of injuries (Chap. 7). Poisoning presents a unique
class of emergency cases (Chap. 8).
Poisonings may result in a generalized hemorrhagic diasthesis.
The evaluations of patients who through examination or treat-
ment have sustained injury are also included in the text
(Chaps. 2.2.12 & 3.2.8). They may have sustained an injury as
a result of the misuse of catheters or the improper insertion of
esophageal or tracheobronchial tubes. A patient requiring
anesthesia or the post-operative patient may be subject to a
unique possibility of unexpected trauma. Another group sus-
tained their injury following ingestion or inhalation of foreign
bodies (Chaps. 2.2.13, 2.2.15, 3.2.1 & 3.2.2).
Radiology is a frequently utilized method of examination of a
traumatized patient. Its use varies with the nature of the injury
and ranges from the techniques used in the emergency patient
who is not breathing to those used in a patient several days af-
ter the trauma and who is not producing urine, to a patient
who is acutely lame.
Table 1.1: Types of trauma or emergency situations
1. Physical trauma
a. physical forces applied suddenly that result in anatomical and physio-
logical alteration
b. gunshot injuries
c. penetrating injuries
d. bite wounds
2. Iatrogenic injuries during examination or treatment
a. incorrectly used catheter
b. inappropriately positioned catheter
c. post-anesthetic recovery problems
d. post-surgical injuries
3. Ingested foreign bodies that result in sudden discomfort
4. Ingested or inhaled toxic agents with sudden clinical signs
5. Acute coagulopathies
6. Combinations of injuries
a. chest wall injury plus lung injury
b. pulmonary parenchymal injury plus diaphragmatic hernia
c. pulmonary parenchymal injury plus pleural injury
d. pulmonary plus mediastinal injury
e. fracture plus diaphragmatic hernia
f. thoracic injury plus spinal, pelvic, or limb fractures
g. thoracic injury plus abdominal injury
7. Abusive injuries
Often radiographic examinations serve to determine which
injuries are life threatening, while other studies are undertaken
to assess the effectiveness of emergency treatment: e.g. the
evaluation of the size of the cardiac silhouette and the size of
pulmonary vessels in the treatment of shock patients, or the
evaluation of persistent pleural fluid following thoracocentesis.
Follow-up studies serve to determine the effectiveness of ther-
apy, for example, by visualising the return of pulmonary func-
tion. The creation of a permanent record may be of help to
the owner and the clinician in understanding the nature of an
injury at a later date.
The case material in this book has been generally divided into
those patients with thoracic trauma followed by those with ab-
dominal trauma and finishing with selected musculoskeletal
cases, soft tissue damage, gunshot wounds, abuse, and poison-
ing. Because of the inclusion of patients with multiple injuries,
this schedule is not followed exactly.
Cases are presented with minimal histories that the reader will
discover are only as accurate as the memory of the owner or
their willingness to share information with the clinician. The
signalment and clinical history of a case can be specific and
they are usually accurate, although you may be presented with
a patient found by a person who knows nothing about the in-
jury nor the animal. The clinical history may be totally accu-
1
1
Chapter 1
Introduction

rate in such cases where the owner has witnessed the traumat-
ic event, whereas other patients are presented with a history
of having been found recumbent or having returned home un-
able to walk normally. Most of these animals are correctly as-
sumed to have been traumatized, while others have diseases
due to another etiology. The reader of this book will discover
that the clinical history presented by the owner is not always
accurate and frequently is generated as a cover-up for a failure
of the owner to present the animal as quickly as would be
thought appropriate. In most of the cases, the results are
known and included in the descriptions. Unfortunately, some
owners chose to reject the offer of treatment and these cases
were returned to the referring clinician, making it impossible
to learn more about the outcome of the case. In others, an un-
expected outcome is discussed. The case material within the
text is presented in a consistent pattern as shown in Table 1.2.
Not all sections are treated equally in each case.
Table 1.2: Presentation of cases
1 Signalment/History
2 Physical examination
3 Radiographic procedure
4 Radiographic diagnosis
5 Differential diagnosis
6 Treatment/Management
7 Outcome
8 Comments
1.1 Characteristics of a diagnostic
radiographic study
Many features need to be considered in how or why to use di-
agnostic radiology in trauma and emergency patients (Table
1.3). In the event of generalized trauma, radiographs of the en-
tire body are suggested as the most rapid means of determin-
ing the general status of the patient. A complete study of the
thorax or abdomen should include two views ventrodorsal
(VD) and lateral, and permit the evaluation of the thoracic in-
let and diaphragm in the thorax, and the diaphragm and pelvis
in the abdomen. If the patient is large, more than one radi-
ograph may be required for each routine view. In cats, it is
possible because of their smaller size and more uniform tissue
density to include the entire patient on a single radiograph.
The use of a “catogram” is to be encouraged in this species.
This technique is not possible in the dog because of the greater
difference in size of the body organs.
The type of radiographic study undertaken may be adapted
according to the clinical signs (Table 1.4). In the trauma pa-
tient, it is usually less stressful to take a dorsoventral (DV) view
of the thorax or abdomen by positioning the patient in sternal
recumbency with the forelegs extended cranially and the hind
limbs in a flexed position. In the seriously injured patient, it is
possible that only a lateral view can be made during the first
examination to avoid further injury. It is desirable in such cases
to make the second orthogonal view later, especially prior to
anesthesia or submitting the patient to surgery.
Table 1.3: Use of radiographic examination in traumatized patients
1. Possible to survey the entire body
a. if a complete clinical report of the trauma is not available
b. if a thorough physical examination cannot be conducted
c. in a manner more extensive than possible by physical examination
2. Possible to limit study only to the area of suspected injury
3. Study can be performed
a. in a non-traumatic manner
b. within a few minutes
c. with minimal cost to the client
d. with relative ease to the patient
4. Possible to diagnose multiple lesions and determine
a. which are life-threatening
b. the sequence of treatment placing life-threatening conditions first
c. prognosis
d. time and cost of treatment
5. Assess the effectiveness of emergency treatment
a. has a hypovolemic status been corrected
b. has a pneumothorax decreased in volume
6. Assess the effectiveness of therapy
a. in the event that clinical improvement is delayed
b. to determine time of discharge
7. Provide a permanent record to enable
a. owner to understand the lesions and treatment
b. evaluation of treatment
c. review of the radiographs
8. Determine preexisting or coexisting non-traumatic lesions and determine
their affect on the outcome of the case
9. Provide additional information if the thoroughness of a physical or
neurological examination is limited by trauma
10. Determine the status of the patient prior to anesthesia
11. Determine the need for an ultrasound examination in emergency
patients
12. Determine the value of presurgical plus postsurgical radiographs
The selection of which lateral view to make or whether to po-
sition the patient in a DV or VD position is often predeter-
mined by the nature of the injury. A bandage or splint placed
on a limb may make certain types of positioning difficult. It is
best to make the first study causing as little stress to the patient
as possible until the nature of the injury is more fully deter-
mined. Subsequent studies from other angles can then be
made, if necessary, for a more complete study.
2 Introduction
1

Table 1.4: The nature of the radiographic study may be altered
to include:
1. Special positioning of the patient or x-ray tube
a. horizontal beam technique
b. oblique views
c. right vs left lateral views
d. dorsoventral (DV) vs ventrodorsal (VD) views
2. Use of contrast studies
a. gastrointestinal contrast study
b. urographic contrast study
I. intravenous
II. retrograde
3. Increase the number and nature of the radiographic views because
of unique trauma
a. stress studies plus routine studies
b. abdominal injury plus spinal fracture
c. thoracic injury plus abdominal injury
1.2 Importance of radiographic
quality
A particular problem with the trauma patient is the difficulty
in positioning or in achieving a diagnostic radiographic study
of the thorax or abdomen. Poor radiographic quality due to
technical error(s) greatly increases the possibility of incorrect
film evaluation. One should avoid the natural tendency to
deny that non-diagnostic radiographs have been produced. It
is easy on poor-quality radiographs to call an artifact or nor-
mal anatomical variation a lesion, resulting in a false-positive
evaluation. More often, the technical errors prevent visualiza-
tion of a lesion, causing a false-negative evaluation.
If a potential technical problem is recognized at the time of the
examination, it is easiest and least expensive to expose anoth-
er film immediately while the patient is positioned on the
table and technical assistance is readily available to assist with
positioning. Remember that a technically compromised image
can result in a missed diagnosis or, worse, a wrong diagnosis.
At its best, this is practicing poor medicine; at its worst, it is
intellectual dishonesty and malpractice. Film is the least cost-
ly part of a radiographic examination, so why not make an ex-
tra exposure if you have any question as to positioning of the
patient and subsequent quality of the radiograph.
Thoracic studies of small animals are usually made with the
patient recumbent causing compression of the lower portion
of the lung so it contains less air than normal (be atelectatic).
The resulting increased fluid density in the dependent lobes
tends to prevent identification of either infiltrative lesions or
space-occupying masses. The compression caused by pressure
of the abdominal contents on the diaphragm, the weight of the
heart and mediastinal structures, and the pressure of the table-
top against the lower rib cage all prevent lobar filling on the
lateral view. The effect of DV vs VD positioning results in ei-
ther the dorsal or ventral portion of the lung being com-
pressed, though it results in a difference that is much less ob-
vious than that seen in the right vs left lateral views.
The studies of skeletal lesions permit fewer variations from the
routine craniocaudal (CrCa), caudocranial (CaCr), and lateral
views. Additional views are usually required due to the nature
of the injury if it limits how a limb can be positioned. Studies
of the spine require care in patient positioning and may de-
mand multiple views to permit a thorough examination of
each vertebral segment. Diagnosis of a fracture on one view
may limit the comparison with the orthogonal view made at a
later time.
A comparison of right and left lateral views, or VD and DV
views, always permits a more complete understanding of the
character of the intrathoracic or intra-abdominal structures
than is seen on a single view. The nature and location of the
suspected lesion influences which view is best for evaluation.
If pleural fluid is free to move, the use of two lateral views or
the DV vs VD views are helpful in providing a more complete
evaluation of the lungs, mediastinum, and thoracic wall. The
movement of peritoneal fluid is difficult to evaluate on radi-
ographs made in different positionings and are of little diag-
nostic value.
Abdominal studies of small animals are usually made with the
patient recumbent causing any intraluminal air to rise, outlin-
ing the more superior portion of the containing organ. When
using liquid gastrointestinal contrast material, positioning be-
comes of particular importance in diagnosis. While air rises to
the superior portion of the hollow viscus, the more dense bar-
ium sulfate meal or iodinated liquid contrast agent falls to the
dependent portion of the organ. It is possible to mix air with
the positive contrast agent in either the gastrointestinal organs
or in the urinary bladder creating double-contrast studies.
In the event of free peritoneal air or fluid, patient positioning
offers little advantage because the free air pools in the most
dorsal portion of the abdomen regardless of the patient’s posi-
tioning and is difficult to visualize using a vertical x-ray beam.
Free peritoneal fluid pools in the dependent portion of the ab-
domen, where it compromises the identification of the serosal
surfaces. Such fluid can be recognized principally because of
this radiographic pattern.
Errors in film processing can destroy the efforts of good pa-
tient positioning and correct film exposure. Processing is
strongly influenced by solution temperature and age of the so-
lutions. Use of automatic processors greatly decreases these er-
rors and makes their use almost mandatory in a progressive
clinic or hospital.
Importance of radiographic quality 3
1

1.3 Use of correct radiographic
technique
The use of correct exposure factors is an absolute necessity es-
pecially in thoracic radiography and incorrect settings are a
frequent technical problem. These can be related to machine
limits, in which instance, it must be realized that your x-ray
machine or imaging system (cassette screens and film) does not
have an adequate capacity for thoracic radiography. With dys-
pnea that often follows trauma, the thoracic contents move
rapidly and an exposure time of 0.01 second or less may be re-
quired to prevent motion artifacts. A longer exposure time re-
sults in movement of the lungs and a reduction in the radio-
graphic quality of the radiograph. The use of a combination of
faster rare-earth-type intensifying screens and appropriate
speed film reduces the radiographic exposure time required
and is an alternative to obtaining a more powerful machine.
Thoracic radiography should use the: (1) highest kVp possible
to allow for use of a decreased mAs, (2) highest mA, and (3)
the shortest exposure time settings possible.
Abdominal radiography is much less demanding since organ
motion is not a particular technical problem. Also, the contrast
between the intrabdominal organs is much lower and the kVp
setting is not as critical. Patient preparation is not a concern in
most trauma or emergency patients. Often the stomach and
bowel are empty, either as a result of the trauma or due to the
patient not eating during the days following the trauma and
prior to presentation at the clinic. The vomiting patient usu-
ally has an empty stomach.
Correct radiographic technique in skeletal studies is not a par-
ticular problem because of the possible use of a bright light that
permits evaluation of an over-exposed study in a manner not
possible in either thoracic or abdominal studies. An under-
exposed view obviously requires a repeat study. Exposure
time is not a problem in studies of the extremities permitting
use of higher detail and consequently slower, film-screen
combinations.
1.4 Use of a grid technique
The use of a grid contributes greatly to improving the diag-
nostic quality of the resulting radiograph by removing much
of the scatter radiation that produces fogging of the film and
loss of contrast. The requirement for its use is dependent on
body thickness and the nature of the organs to be radio-
graphed. Grids can be satisfactorily used in either a stationary
mode, in which the grid lines are seen on the radiograph, or
in an oscillating mode that moves the grid during the exposure
time and blurs the grid lines so that they do not create the po-
tentially disturbing parallel lines on the resulting radiograph. A
radiograph made using a fine-line stationary grid has visible
grid lines that are fine enough so as to not significantly reduce
image quality even when used in a stationary mode. The use
of a grid requires a marked increase in the radiographic expo-
sure and the type of grid selected should permit the use of an
exposure time that is short enough to prevent patient motion.
The compromise in the use of a grid is that the improvement
in film quality through increased contrast resulting from the
limitation of scatter radiation must not be negated by patient
motion causing a loss in detail.
A grid is particularly helpful on thoracic studies in dogs whose
thoracic measurements are greater than 15 cm. In the smaller
patient, the less dense lungs create a minimal amount of scat-
ter and the use of a grid in a thoracic radiograph is not re-
quired, though if the thoracic cavity contains pleural fluid or
abdominal organs, the grid may be helpful with thoracic meas-
urements over 11 cm. In addition, an obese patient with thick
thoracic walls requires the use of a grid at smaller body meas-
urements.
Because the density of the abdominal contents in a normal pa-
tient is equivalent to water, trauma does not usually result in a
marked alteration in their density and little variation is noted
in the amount of scatter radiation produced. Thus, use of a
grid in abdominal radiography is always recommended with
patients that measure more than 11 cm.
According to these recommendations, the use of a grid is not
commonly required in studies of the thorax or abdomen of a
cat. The use of a grid is required in radiography of the muscu-
loskeletal system in studies of the spine, shoulder joint, or
pelvis/hip joint in which the thickness of the tissues exceeds
11 cm.
1.5 Selection of intensifying
screens
The best film-screen combination for radiography of the trau-
ma patient, in the event your x-ray machine has limited pow-
er, is fast rare-earth-type screens and matching high-latitude
film. This combination permits the use of shorter exposure
times and produces low-contrast radiographs without motion
artifacts. If your x-ray machine is of a higher milliamperage
rating, you have the choice of selecting a slower speed screen
and film combination, and still achieve an adequate radio-
graphic exposure at a short exposure time. The use of a slow-
er speed system, especially in extremity studies, improves
radiographic quality since the resulting radiograph is much less
grainy.
1.6 Radiographic viewing
The radiographs should be dry at the time of evaluation. Wet
tank processing often prevents this, since it is often necessary
to evaluate the radiographs immediately following their pro-
4 Introduction
1

cessing to make a decision concerning keeping the patient in
the clinic or sending it home. While the radiograph should be
re-evaluated following drying, the time required for this is of-
ten not taken. The errors in diagnosis associated with this
problem alone offer justification for acquiring an automatic
processor that permits an immediate examination of a dry
radiograph.
Viewing conditions greatly affect your perception of image
quality. Even though it is highly unlikely, surroundings should
be quiet at the time of film evaluation so that your full atten-
tion can be directed toward the radiographs. If possible, it
would be best to use an area away from busy clinic activities.
An adequate source of illumination is basic for radiographic
evaluation. The use of a ceiling light bulb is not adequate, nor
is sunlight beaming through a window that is most likely
streaked with dirt. Why do we work so hard to make a diag-
nostic radiograph and then evaluate it under the worst of con-
ditions?
Even with the use of good film viewers, the areas of brightly
illuminated viewing surface surrounding a smaller radiograph
often used in skeletal radiography reduce the perceived con-
trast drastically, as the eyes adjust to the bright light making it
difficult, even impossible, to see the darker areas on the radi-
ograph. If possible, eliminate such extraneous light sources by
using cardboard blockers on the viewboxes placed around the
radiographs. It is interesting that viewers of this type with
built-in “shades” have been available and are in common us-
age in European countries for the past 40 years, but, for some
unknown reason, viewers of this type are difficult to locate in
the United States.
Another problem is that of bright room light reflecting off the
radiograph. This can be rather easily corrected by decreasing
the room illumination or even moving into a darkened room
for film evaluation. A less common problem in radiographic
evaluation is the uneven illumination in the viewboxes from
different types or different ages of light bulbs or fluorescent
tubes.
Often in skeletal radiography, the high contrast between bone
and soft tissues makes evaluation of the interface difficult.
Thus, early bony callus, post-traumatic periosteal new bone,
or minimal soft tissue calcification can be inadvertently over-
looked. The use of a separate bright light is helpful in the eval-
uation of these portions of the radiograph and this technique
has also a special importance in the evaluation of overexposed
radiographs.
1.7 Radiographic contrast
The term radiographic contrast refers to the comparison of
shadows of different film densities. In skeletal radiography, the
difference between one region of film density and an adjacent
region is great. The greater the film contrast, the more
“sharply” or “clearly” the margin of a bone organ or structure
appears on the radiograph. Another method to describe the
radiograph is to refer to a scale of contrast, which takes into
account the entire range of shades of gray from white to black.
In skeletal radiography, the dense bones are contrasted with
the less dense soft tissues surrounding them so the contrast is
high. Still, contrast can be diminished or lost by overexposure
or overdevelopment resulting in a radiograph that prevents
light from the viewbox from penetrating the periphery of the
film and results in an image “without identification of any soft
tissues around the bone”.
1.8 Film density versus tissue
density
Frequently, the use of the term density is confusing because it
can refer to film density or tissue density. Film density refers
to the “blackness” of a film, i.e. the most black portion of a
film prevents light from the view box from penetrating the ra-
diograph and is said to have the highest film density. Thus de-
fined photometrically, density is the opacity of a radiographic
shadow to visible light and results from photons having
reached that portion of the film. These areas become black af-
ter processing, preventing light from reaching the eye during
examination of the radiograph.
However, density can also be used to describe tissue that has
a high weight per unit volume and so prevents photons
from reaching the film resulting in an area of lessened film
blackening, or whiteness. Tissue density and film density are
therefore inversely proportional. The tissue with the highest
density causes the highest attenuation of the x-ray photons and
produces the lightest (most white) shadow on the radiograph
creating a low film density. The term density should be used
only when specifically defining whether it refers to tissue
density or film density.
1.9 More about “density”?
Bowen A D. Not DENSITY! Are you Dense? Radiology
176:582, 1990.
Density is a noun, but to be radiologically meaningful it must
be qualified by indicating whether it is greater or less than
some reference density. The reference density is generally un-
derstood to be that of the normal tissue (e.g., lung, muscle,
bone) that surrounds the shadow in question. For example,
“This increased density in the bone is caused by fragment su-
perimposition”. Thus qualified, density also can be used as
part of a modifier: “a zone of increased density” meaning tis-
sue that is of greater density than expected.
More about “density”? 5
1

The choice of “density” as a description of a radiographic
change is unfortunate. What we call “increased density” on a
radiographic film actually results from a higher tissue density
causing less darkening of the film in an area in which fewer
photons have interacted resulting in a reduced deposition of
silver ions. Are there better terms that we could use? Ra-
diopacity is most exact, for it denotes an attribute of the ob-
ject: the tissue’s impenetrability to x-rays rather than the re-
sultant degree of exposure of the film. Opacity is a truncation
of radiopacity and is equally acceptable. Or, perhaps to make
things clearer, we should think in terms of “a patch of in-
creased density”, “a shadow of water density”, or “a lesion
similar to bone density”.
The appearance of the body’s tissues in CT scans is similar to
radiographs since it is based on the absorption and transmission
of x-rays. In CT terminology, “attenuation” is a collective
term for the processes of absorption and scattering by which
the energy of an x-ray beam is diminished in its passage
through matter. Thus, a “high-density lesion” becomes more
appropriately a “high-attenuation” lesion; this terminology
could also be used with diagnostic radiology.
1.10 The art of radiographic
evaluation
Radiographic evaluation is an art and as such, is an acquired
skill where both proficiency and expertise develop slowly.
This skill cannot be attained by reading about radiology and
passing multiple choice examinations about the subject. Ac-
quisition of this skill can be facilitated by learning the princi-
ples of radiographic evaluation, which are then applied to rou-
tine radiographic examination. Regardless of the hours spent
in the study of books, a skill in radiographic evaluation is pri-
marily acquired by practice, preferably with a skilled teacher
as a guide, using selected cases that illustrate the specific prin-
ciples or features. The untrained or inexperienced reader
makes many more errors than the trained reader.
What does radiographic evaluation or radiographic interpreta-
tion mean? It is a series of conclusions drawn as a result of the
application of a systematic, learned and practiced method of
analytical searching of the shadows on the radiographs, which
with knowledge, come to take on a special meaning: instead
of being an incoherent mass of shades of gray, the shadows ac-
quire life and clinical importance.
Learning normal radiographic anatomy is important since as in
all clinical medicine, the most difficult decision is the deter-
mination of whether an observation is within normal limits or
is indicative of disease. This learning can be enhanced through
the study of a series of normal studies or by radiographing the
opposite limb of the patient. Many practitioners become dis-
couraged because the skill in evaluation of a radiograph does
not develop quickly. Yet, we forget the time required to come
to an understanding of the varieties of lung sounds. The learn-
ing of any diagnostic method will continue throughout your
career and can be enhanced as long as you conscientiously
practice it; the same applies to diagnostic radiology.
1.11 Methods of radiographic
evaluation
There are two basic methods of radiographic evaluation. The
first is to memorize the radiographic features of a selected dis-
ease. It is natural for us to want to believe that the course of a
disease will follow a set pattern. This approach is taken by tra-
ditional textbooks of medicine, in which diseases are present-
ed with a description and an illustration of the typical pro-
gression of the disease, including in some cases sample radio-
graphs. We are taught in this manner in school and accept the
unmistakable example of a disease as classical. Unfortunately,
disease only rarely appears in this manner in true life. Thus, we
associate a classical radiographic picture with a specific bone
disease and the features can become so fixed in our mind that
we demand their presence to assure the diagnosis. If it were
possible to effectively teach radiology in this way, radiologists
would not be required to teach it and radiographic diagnosis
would be taught in medicine courses.
The error with using this approach in radiographic evaluation
is similar to the difficulty found in applying textbook know-
ledge to the reality of a sick animal. The clinical information
derived from a patient often is indefinite and ambiguous, and
it is the same with radiographic findings. In many patients,
unfortunately, the picture of the disease as seen on a radio-
graphic study as well as the clinical picture of the disease are
not “typical”, and the textbook approach therefore leads to
confusion or misdiagnosis. It is sometimes said that the “pa-
tient hasn’t read the text book” and thus, does not know how
the lesion should appear radiographically.
A second and much more accurate method of radiographic
evaluation uses radiographic signs or patterns or features. It in-
volves a complete examination of the radiograph, searching for
evidence of pathophysiology, and relating the resulting radio-
graphic features to the various conditions that are known to
cause them. As there are often many signs or patterns on a ra-
diograph, a systematic analysis using deductive reasoning often
leads to the appropriate differential diagnosis.
1.12 Preparing the radiological
report
A discussion of the radiological report is thought to be impor-
tant at this time even though you may feel that it is not neces-
sary in your practice environment. The radiographic findings
need to be recorded somewhere in your clinical record even if
6 Introduction
1

this is only a statement that radiographs were made and a brief
comment of your evaluation. You can record a written report
on: (1) the film storage envelope, (2) the clinic record, or (3) a
separate radiographic report. Considering what should go into
the report can assist you in considering some of the many
questions relative to a study that you might otherwise not con-
sider. While the report can be brief, it is helpful if it contains
information that might be required in assisting you with a sub-
sequent medicolegal problem.
By answering the questions listed below, you will be remind-
ed of the additional areas you need to examine on the radio-
graph. Thus, having to answer specific questions is an excel-
lent technique for forcing a more complete examination of the
radiographs. Such questions are influenced by the type of
people to whom you will communicate your findings and
how will this communication take place? The report may be
only for yourself, a colleague in your practice, a colleague to
whom the case will be referred, or for the owner. The report
may be written or delivered verbally. Your relationship to the
case usually determines to whom you report the findings. If
you are the primary care clinician, you are probably “talking
to yourself” or perhaps to a colleague in the clinic. If this is a
referral patient, you need to report the findings to the in-
dividual who referred the case to you. If the patient is to be
referred by you to another clinic, you need to tell that person
what you have found on the study (of course, you can just send
the radiographs with a note that you did not have time to eval-
uate them).
Whatever the method of reporting the findings is used, the
most complete report would include the following informa-
tion: (1) a description of patient including the breed, sex, and
age, patient number, date, and name of your clinic, (2) a de-
scription of the radiographic study including the anatomical
region evaluated and any special techniques used such as stress
views or oblique views, (3) a note concerning the technical
quality of the radiographs, (4) a comment on any limitations
in the study due to problems in positioning or on the number
of views that were made, (5) a description of the appearance
and location of the major lesion using acceptable and under-
standable terms, (6) a brief comment concerning any second-
ary lesions such as a congenital/developmental lesion or a de-
generative lesion, and (7) your diagnosis, definitive or differ-
ential. The inclusion of any information to explain why the ra-
diographic study was not complete can be of great value to you
during subsequent litigation.
It is obvious that on even a causal review, this can involve a
great deal of time spent on a single radiographic study. As with
most things in life, the more time you force yourself to spend
in preparing a radiographic report, the more you will put into
the thought it takes to make the radiographic evaluation, and
the more information you will derive from the study. An-
swering the questions listed above forces you to give thought
in a manner that can prevent you from making some foolish
errors.
1.13 Terms to understand
in radiology
Aggressive radiographic changes refer to a pattern that is
rapidly changing and is often associated with a malignant le-
sion. These changes can be seen, for example, in a lesion in
which malignant transformation of a fracture is secondary to
a chronic inflammatory environment or a pathologic fracture
extending through a primary bone tumor
Benign radiographic changes refer to a pattern that is
slowly changing and is often associated with a benign lesion.
Most traumatic lesions are benign in appearance.
Bone density refers to the high mass per unit volume of bone
tissue reflecting the high density of the bone. Evaluation of
this feature is important in the detection of a pathologic frac-
ture in which the volume of bone tissue is diminished.
Clinical data or signalment refers to the patient’s name, age,
sex, breed, symptoms, and laboratory findings. Their consid-
eration is important in achieving the correct interpretation of
a radiograph or at least in making a complete differential diag-
nosis.
Clinical history refers to the information provided by the
owner concerning the events leading up to the development
of particular clinical signs. The history may also include infor-
mation derived from a previous medical record. Unfortunate-
ly, this information is not always correct and is often not com-
plete.
Comparison studies refer to radiographs made of the oppo-
site limb that provide a normal comparison and are especially
valuable in skeletally immature patients. Comparison studies
can help in the determination of a trauma-induced error in
bone organ growth.
Density can refer to mass per unit volume of tissue, in which
case bone has a high density. Density can also refer to the
blackness of the radiograph, which is determined by the
amount of silver present following processing of the film. Thus
the two terms, tissue and bone density, are inversely propor-
tional; e.g., a bone with high tissue density produces a shad-
ow on the radiograph that is white and is of low photograph-
ic density.
Diagnostic scheme refers to a system for reaching a deter-
mination of a differential or definitive diagnosis by combining
the clinical findings, findings from the physical examination,
laboratory findings, and the results of diagnostic imaging.
Differential diagnosis refers to the decision that the clinical
data, findings from physical examination, laboratory findings,
plus particular radiographic features are ambiguous and suggest
the possibility of more than one cause for the clinical signs list-
ed in an order of decreasing probability.
Terms to understand in radiology 7
1

Film refers to the unexposed radiographic film and is the term
usually used through the process of film exposure and film
processing. At the time the film is evaluated, it is referred to as
a radiograph or a diagnostic radiograph.
Film density refers to the darkness on the radiograph and is
inversely proportionate to tissue density. More specifically, it
is a measurement of the percentage of incident light transmit-
ted through a developed film. It is also known as radiograph-
ic density.
Film-screen combination refers to the matching of a pair
of intensifying screens with a particular x-ray film. Both
screens and film are produced to have different speeds that re-
flect the number of x-ray photons required to produce a diag-
nostic radiograph. The combination is often given a numeri-
cal value (100 often refers to an older standard that is still com-
monly used, the “par” screen system).
Film speed refers to the size and nature of the crystals in the
film emulsion that determine the radiographic exposure re-
quired to produce a given film density.
“Follow-up” studies refer to a subsequent radiographic
study made to elucidate the information contained within the
first study.
Grid refers to a devise consisting of alternating strips of lead
and a radiotransparent medium which are oriented in such a
way that most of the primary radiation passes through, while
most of the scattered radiation is absorbed. A grid is used com-
monly in abdominal studies but uncommonly in patients with
traumatic injury to the musculoskeletal system.
kVp refers to the kilovoltage peak or potential and is the max-
imum potential difference applied between the anode and
cathode by a pulsating voltage generator.
“Leave me alone” lesions refer to lesions not thought to be
life-threatening and in which biopsy is thought to be non-
rewarding or even contraindicated.
Lucency refers to a black shadow on the radiograph created
by low tissue density (or radiolucency). The term is also to
describe a bone lesion with less than normal bone tissue (lytic
lesion).
mAs refers to a combination unit that is the product of the
tube current expressed in milliamperage and the exposure time
expressed in seconds. It determines the number of photons
produced during an exposure.
Opacity refers to a white shadow on the radiograph create by
high tissue density (also, radiopacity).
Patient rotation refers to a position in which the limb, head,
spine, or pelvis are at an unusual angle to the tabletop result-
ing in an atypical radiograph. Hopefully, this is a planned
rotation to achieve a more diagnostic study and not one that
resulted from accidental malpositioning of the patient.
Radiograph refers to an x-ray film that has been exposed
during a diagnostic radiographic study and contains informa-
tion following processing that can lead to a radiographic diag-
nosis.
Radiographic density refers to the blackness on the radio-
graph that is determined by the amount of silver present fol-
lowing processing of the film.
Radiographic pattern refers to a characteristic change seen
on the radiograph and is related to a pathophysiological change
(also called a radiographic feature).
Radiography refers to the technique of patient positioning,
film exposure, and film processing that results in the produc-
tion of a diagnostic radiograph.
Radiology refers to the medical speciality in which radio-
graphic film is exposed during a radiographic examination,
thereby producing a radiograph that is subsequently examined.
Thus, radiology is the term used to describe the entire field of
radiography and radiographic diagnosis. This term is now al-
tered somewhat since the results of many examinations are
digitalized and a radiographic film is not used.
Radiolucent refers to a black shadow on the radiograph cre-
ated by low tissue density that has permitted passage of pho-
tons (also lucent or lytic shadow).
Radiopacity refers to a white shadow on the radiograph cre-
ated by high tissue density that has prevented the passage of
photons (also opaque shadow)
Radiopaque refers to the ability of tissue to absorb x-ray
photons.
Recumbent indicates that the patient is positioned with its
body laying on the table-top.
Repeat studies (films) are additional radiographic views
made following the discovery that the first radiographs were
nondiagnostic for some reason.
Roentgen refers to the Professor of Experimental Physics at
Wurzburg, Germany who discovered x-rays on November 8,
1895. The term is synonymous with x-ray (also roentgen
beam or x-ray beam).
Sequential studies refers to subsequent radiographic studies
made to record a change in the radiographic appearance of a
lesion (also follow-up study).
8 Introduction
1

Signalment refers to the patient’s name, age, sex, breed,
symptoms, and laboratory findings and are important in assist-
ing in the correct interpretation of a radiograph.
Skyline view refers to a special method of patient position-
ing that allows the x-ray beam to be directed so it projects a
particular bone or part of a bone free of the surrounding skele-
tal structures.
Stress studies refer to the special positioning of a body part
in an unnatural anatomical position to determine the status of
the soft tissues supporting a joint or for the detection of a small
fracture fragment.
Standard positioning refers to the positioning of the patient
used for a routine radiograph, i.e. craniocaudal, dorsopalmar,
dorsoplantar, lateral, dorsoventral and ventrodorsal, etc.
Suspect diagnosis refers to a disease that is suspected to be
the cause of the clinical signs present in a patient. Such a diag-
nosis can be made, or changed, at any time during the acqui-
sition of additional information from various diagnostic stud-
ies.
Technical error refers to a mistake in the exposure or pro-
cessing of a film, or in the positioning of the patient that re-
sults in a radiograph, in which the ability to diagnose a lesion
is compromised.
Tissue density refers to the weight per unit volume of a body
part and is inversely proportional to film density.
Terms to understand in radiology 9
1

2.1 Introduction
2.1.1 Value of thoracic radiology
Radiology is a most important diagnostic tool in the investiga-
tion of thoracic trauma because it reveals more specific infor-
mation than a physical examination and can be easily per-
formed in an inexpensive, quick, and safe manner, thereby
providing rapid results on which to base decisions relative to
diagnosis and/or treatment. The x-ray image is a transillumi-
nation of the body at the moment the film is made. It is this
ability to see a representation of the interior of the patient, im-
possible by palpation or auscultation that accounts for the great
value of thoracic radiography. The good contrast provided by
the air in the lungs opens up a window to the thoracic organs
on non-contrast radiographs to an extent not possible with the
abdominal radiographic study. Accurate radiographic diagno-
sis is vital because physical signs of thoracic organ dysfunction
following trauma are often ambiguous. In addition, a radi-
ographic study provides a temporal dimension that permits
evaluation of changes as they appear in the progression of a dis-
ease. Comparison of studies reveals the success or failure of
treatment and can show the development of unexpected con-
sequences, such as a post-traumatic pneumonia in a contused
lung. Radiographs reproduce the character of the patient’s
thorax on film that can be examined both at the time of the
original examination as well as later.
While thoracic injuries are common and often life threaten-
ing, the thorax and its contents are not as easily injured as
might be expected. The thorax is tough and resilient due to its
strong, spring-like ribs. The lungs add protection against
impact to the heart through their air-cushion effect. Because
of this protection, virtually all clinically important thoracic
injuries are due to high-energy forces generated by violent
trauma. Puncture or crushing wounds are other forms of trau-
matic injury to the thorax that do not usually involve high-
energy and yet can be extremely damaging. Thoracic injuries
are often part of a constellation of injuries involving several
areas of an animal’s body.
2.1.2 Indications for thoracic radiology
The clinical situations suggesting the need for thoracic radio-
graphy include: (1) patients with known or suspected thoracic
trauma, (2) patients with trauma-induced respiratory dysfunc-
tion, (3) patients in shock, (4) trauma patients prior to surgery,
(5) older patients with concurrent disease thought to compro-
mise recovery from the traumatic injury, or (6) age-related
pulmonary or cardiac disease thought to compromise the trau-
matic injury. Another reason for thoracic radiography is to
evaluate known or suspected non-cardiogenic edema follow-
ing several types of uncommon trauma such as electrical
shock, near-drowning, head trauma, or near-asphyxiation.
2.1.3 Patient positioning
Positioning of the patient influences the appearance of tho-
racic organs. In certain trauma patients, the manner of posi-
tioning is predetermined by the nature of the injury. In oth-
ers, positioning can be selected for the study that is felt to of-
fer the best opportunity of evaluating a particular portion of
the thorax. For example, in a dog with a thoracic wall injury,
it is possible to consider placing the injured side next to the
tabletop in an effort to achieve the smallest object-film dis-
tance; however, there may also be the need to place the in-
jured lung lobes in a superior position, so that they can attain
maximum inspiration and thus create a better opportunity for
accurate radiographic evaluation. It is difficult to make firm
recommendations concerning positioning and the effect of
variation in body positioning needs to be understood before
any decision is made (Table 2.1).
thoracic studies
first technique is to “memorize” the appearance of all disease
or pathologic changes that might be found in a traumatized
thorax, and then examine the radiograph looking carefully for
those changes. An approach of this type is taken by tradition-
al textbooks of medicine, in which diseases are presented with
a description and an illustration of the typical radiological ap-
pearance. The difficulty with this approach is similar to the
difficulty found in applying textbook knowledge to the reali-
ty of a sick animal. Clinical information of the traumatized pa-
tient is often indefinite and ambiguous. It is the same with the
information available from a radiograph. In many patients, the
radiologic picture of a disease is not “typical”, and the text-
book approach therefore can lead to confusion or misdiagno-
sis.
2
Chapter 2
Radiology of Thoracic Trauma

Table 2.1: Effect of positioning on the appearance of thoracic
radiographs
1. Left side down, lateral view
a. dependent organs in the abdomen are moved cranially
I. the air bubble in the fundus of the stomach is moved cranially
II. the left crus of the diaphragm is more cranial.
III. the air bubble in the pyloric antrum is caudal to the right crus of the
diaphragm.
b. the caudal vena cava silhouettes with the right crus as it penetrates
this structure and is more caudal in position
2. Right side down, lateral view
a. dependent organs in the abdomen are moved cranially
I. the air bubble in the fundus of the stomach is moved caudally
II. the right crus of the diaphragm is more cranial.
III. the air bubble in the fundus of the stomach is caudal to the left crus
of the diaphragm.
b. the caudal vena cava silhouettes with the right crus as it penetrates
this structure and is more cranial in positioning
3. Dorsoventral view
a. the x-ray beam strikes the diaphragm at nearly a right angle
b. a distance equal to the length of 3–4 vertebral bodies exists between
the shadow of the ventral portion of the diaphragm (the cupula) and
the two dorsally located crura
c. the heart “hangs” in a position on the midline that is more anatomical-
ly correct
4. Ventrodorsal view
a. the x-ray beam strikes the diaphragm almost parallel to its surface;
b. a short distance exists between the shadow cast by the ventral portion
of the diaphragm (the cupula) and its two dorsally located crura
c. the heart “falls” laterally, a malposition more evident in a deep-chested
patient
A more accurate method of radiographic evaluation uses the
identification of a particular “radiographic sign” that is indica-
tive of specific pathophysiologic changes and an understanding
of the diseases in which that particular sign is known to occur.
As there are often many such signs on a radiograph involving
more than one organ, a systematic analysis using deductive
reasoning often leads to the appropriate differential diagnosis.
Any successful examination of a radiograph must be systemat-
ic in order to ensure that all parts of the radiograph are fully
examined. The best system is anatomical and includes the con-
scious examination of each anatomical structure within a giv-
en region in the body. Identification of bronchi, arteries and
veins, and interlobar fissures directs the evaluation toward
each individual lung lobe. Start the examination centrally,
proceed next to the mid-lung, and finally examine the peri-
phery of the lung, looking for any radiographic pattern that is
different and thus, indicative of disease.
Compare the appearance of the right and left lung fields, or
the adjacent lung lobes. Look especially for unusual tissue den-
sity, unequal degrees of inflation, and change in the size or
number of vascular structures within the lung. The configu-
ration of a patient’s thorax can be deep and narrow, interme-
diate, or shallow and wide, and this configuration influences
the appearance of the lung fields. Pulmonary vessels and
bronchi need to be examined equally on both the lateral and
DV or VD views.
The appearance of the heart on both orthogonal radiographic
views is important in generating the true character of the heart
in three dimensions. Configuration of the thorax greatly in-
fluences the appearance of the heart shadow. In addition,
shock causes hypovolemia and microcardia, whereas hemo-
pericardium gives the appearance of cardiomegaly. The
change in patient position from DV to VD alters the appear-
ance of the heart shape, whether normal or pathological.
In the normal patient, the pleural space cannot be visualized.
In the trauma patient, this normally minimal space may be
filled with hemorrhage, chyle, pleural fluid, air, or abdominal
viscera. The pleural contents can have a generalized or focal
location, and can move or be fixed in position.
The mediastinal space contains the heart plus the air-filled tra-
chea, usually an empty esophagus, aorta and other major ves-
sels, and lymph nodes. This space is divided radiographically
into: (1) the cranial mediastinal space, that contains the tra-
chea, esophagus, great vessels, thymus, and the sternal and cra-
nial mediastinal lymph nodes; (2) the central mediastinum that
includes the heart, aortic arch, esophagus, tracheal carina, and
the hilar region with its major vessels and lymph nodes; and
(3) the caudal mediastinum that includes the descending aorta,
esophagus, and caudal vena cava. These structures are partial-
ly hidden from visualization on the radiograph in the normal
patient by the accumulation of mediastinal fat and the absence
of any air-filled structures that provide contrast other than the
trachea. The mediastinum in the trauma patient can be filled
with blood (hemomediastinum) causing an increased size, in-
creased fluid density, and a complete loss of visualization of the
mediastinal organs. It may also be filled with air (pneumome-
diastinum) causing a reduction in tissue density that contrasts
with the mediastinal organs making them more easily identi-
fiable. Both air and fluid may be found in some trauma pa-
tients. In rare trauma cases, the mediastinum can be filled with
a mass lesion such as a herniated abdominal organ or blood
clots following a hemomediastinum creating a mass-lesion ef-
fect.
The thoracic wall includes the vertebrae, sternebrae, and ribs,
including the costovertebral joints, costochondral junctions,
and costal cartilages. The most common post-traumatic
changes in the thoracic wall include subcutaneous air and soft
tissue swelling in addition to the injuries to the ribs. Other
radiographic changes seen in the thoracic wall are artifactual
and include shadows caused by nipples, skin nodules, skin
folds, wet hair, dirt and debris, bandage material, and subcuta-
neous fat.
Examination of the position and shape of the diaphragm is of
great importance in detecting injury to that structure. On the
lateral view, the angle between the diaphragm and spine may
Radiographic evaluation of thoracic studies 11
2

vary with the phase of respiration. The angle in inspiration is
smaller as the diaphragm moves caudally and becomes more
parallel to the spine. The triangle formed by the caudal border
of the heart, the ventral portion of the diaphragm, and the
caudal vena cava is another indicator of the position of the dia-
phragm and the degree of inspiration. This space is smaller on
expiration preventing evaluation of that portion of the lung.
On the DV or VD view, the angle between diaphragm and
thoracic wall can vary slightly. On both views, the diaphragm
is more cranial and convex and has greater contact with the
heart on expiration. This position, though, may result in a
superimposition of a part of the heart shadow over the dia-
phragm causing summation. The heart shadow appears rela-
tively larger on the expiratory film because of the diminished
size of the thoracic cavity. The ribs are closer together and at
a greater angle with the spine on expiration.
The stage of respiration during radiography influences the
radiographic appearance of the thorax, but this may be impos-
sible to control in the trauma patient. A film exposed in expi-
ration has significantly different features when compared with
those exposed at full inspiration, and these are sufficient to
cause misdiagnosis of lung disease. At expiration, the lungs are
relatively more radiopaque and smaller in size and appear to
contain an increased amount of fluid. Because of the manner
in which the patient breathes, especially a trauma patient
placed in position on an x-ray table, the movement of the di-
aphragm is relatively minimal, often no more than 5–10 mm,
thus the discussion of attempting to make the exposure in in-
spiration is usually a moot one.
Panic breathing in the trauma patient often causes aerophagia
and filling of the stomach with air (Case 2.53).
2.1.5 Radiographic features
in thoracic trauma
The major types of structural damage to the thorax caused by
trauma can be divided into five categories: (1) thoracic wall
disruption, (2) pleural fluid or air, (3) diaphragmatic hernia
with resulting pleural fluid and pleural masses, (4) lung
parenchymal injury, and (5) mediastinal injury. These and
other features of thoracic trauma are presented in the follow-
ing.
2.1.5.1 Disruption of the thoracic wall
The traumatized chest wall often has lesions due to injury to
the soft tissue and ribs (Table 2.2). Radiography can define and
evaluate the extent of the underlying damage. Injury of the
chest wall results in a diminished respirational efficiency and
restricted expansion of the rib cage. The soft tissues often sus-
tain major injuries since they are not well protected. Ra-
diopaque debris is often found on and under the skin. Sub-
cutaneous emphysema is common and is usually secondary to
a break in the skin, but can be associated with an internal in-
jury in which air leaks into the subcutaneous compartment,
e.g. injury to the trachea (Table 2.3).
Skeletal structures can be injured in the traumatized patient
and examination of the vertebrae, sternebrae, ribs, costochon-
dral junctions, and the proximal part of the forelimbs should be
complete. Injury to the ribs is most frequent and the fractures
are usually simple. A combination of fractures can create an
unattached segment of thoracic wall and cause a “flail” chest
and a unique form of injury with paradoxical thoracic wall
motion. Injuries to the sternebrae are usually not of great clin-
ical importance, but add information concerning the nature
and severity of the trauma. It is also important to differentiate
between open and closed thoracic wall injuries.
Detection of fractures of the surrounding bony structures can
suggest the cause and location of the thoracic trauma. It fol-
lows that a patient with rib fractures can be assumed to have
sustained underlying lung trauma. Often the appearance and
bilateral location of the fractured ribs suggests puncture
wounds as would be associated with dog bites. Fractures/lux-
ations of the thoracic vertebrae, if without marked segmental
displacement, can be overlooked because of not causing any
obvious neurologic signs or problems in locomotion.
Furthermore, the location of the injured thoracic wall directs
attention to the underlying pleura and lung, and often reveals
a pocketing of pleural fluid associated with a collapsed lung
lobe. Pneumothorax may be detected instead of pleural fluid.
Radiographs prove helpful in the evaluation of secondary
changes, such as pulmonary and/or mediastinal hemorrhage
with mediastinal shifting, or diaphragmatic rupture with dis-
placement and/or incarceration of the viscera.
2.1.5.2 Pleural space
In the trauma patient, this normally minimal space can be
filled with fluid (pleural effusion, hemorrhage, or chyle), or air
(pneumothorax), or can contain abdominal viscera (diaphrag-
matic hernia). Pleural fluid can be freely movable, trapped, or
loculated; however, in trauma patients the fluid is often freely
movable. A mass lesion associated with a diaphragmatic hernia
can be generalized or focal depending on the viscera that are
displaced into the thoracic cavity.
2.1.5.3 Pneumothorax
Pneumothorax is the collection of free air within the pleural
space, resulting in a loss of intrathoracic negative pressure, thus
allowingthelungstorecoilawayfromthethoracicwall.Itisone
of the most common sequelae to thoracic trauma and can be
found with penetrating chest wall injuries or, more commonly,
following rupture of the lung parenchyma or bronchi with an
intact chest wall. Tension pneumothorax is a unique form of
pneumothorax and is fortunately not common (Cases 2.59–
2.61). Usually, a pneumothorax is bilateral because the thin
mediastinumruptureseasilyatthetimeoftheoriginaltraumaor
because it is fenestrated; however, it can also be unilateral.
2

Table 2.2: Radiographic features of thoracic wall injury
1. Features on lateral view
a. soft tissues
I. swollen (Cases 2.11 & 2.19)
II. subcutaneous air (Cases 2.1, 2.3, 2.12, 2.38, 2.58 & 2.62)
i) pockets
ii) linear distribution
b. debris on skin or within soft tissues (Cases 2.6, 2.12)
c. injured soft tissues (Cases 2.14, 2.19 & 2.38)
I. intercostal muscle tear
II. lacerated muscle
d. ribs
I. fractures
i) undisplaced fragments (Cases 2.24 & 2.30)
ii) malpositioned fragments (Cases 2.12, 2.37 & 2.52)
iii) multiple fragments (“flail chest”) (Cases 2.4, 2.5 & 2.9)
II. costovertebral luxation (Cases 2.16 & 2.56)
III. separated ribs (intercostal muscle tear) (Cases 2.3 & 2.58)
IV. injured soft tissues (Case 2.7)
V. injury to the costal arches is often not noted (Case 2.45)
e. sternal injury (Cases 2.5 & 2.7)
f. pleural space underlying the thoracic wall injury
I. fluid (hemorrhage)
II. air (pneumothorax) (Case 2.3)
g. lungs adjacent to the thoracic wall injury
I. retraction from thoracic wall (pneumothorax and atelectasis)
(Cases 2.3, 2.65 & 2.68)
II. increased density (contusion) (Cases 2.4, 2.5 & 2.7)
h. paracostal hernia (Cases 2.14, 2.16 & 2.17)
2. Features on VD or DV view
a. soft tissues
I. swollen (Cases 2.2, 2.19 & 2.20)
II. subcutaneous air (Cases 2.30, 2.38, 2.58 & 2.61)
i) pockets
ii) linear distribution
b. debris on skin or within soft tissues (Cases 2.6 & 2.82)
c. injured soft tissues (Cases 2.63 & 2.82)
d. ribs
I. fractures
i) undisplaced fragments
ii) malpositioned fragments (Cases 2.2, 2.8, 2.19 & 2.52)
iii) multiple fragments (“flail chest”) (Cases 2.4 & 2.5)
II. costovertebral luxation (Case 2.16)
III. costochondral luxation
IV. separated ribs (intercostal muscle tear) (Case 2.14)
e. pleural space
I. fluid (hemorrhage) (Cases 2.19 & 2.31)
II. air (pneumothorax) (Cases 2.37, 2.54 & 2.55)
f. lungs adjacent to the thoracic wall injury
I. retraction from thoracic wall (pneumothorax and atelectasis)
(Cases 2.3, 2.65 & 2.68)
II. increased density (contusion) (Cases 2.24, 2.30 & 2.32)
g. paracostal hernia (Cases 2.14, 2.16 & 2.17)
Pneumothorax that develops in the absence of trauma is con-
sidered spontaneous. It may be a primary spontaneous pneu-
mothorax or a secondary spontaneous pneumothorax, i.e. is a
sequela to chronic parenchymal lung disease. It is difficult to
determine the influence of trauma in many patients with
Table 2.3: Origin of air in subcutaneous emphysema
1. Following a penetrating wound to the thoracic wall
a. skin laceration permits entry of air (Cases 2.2, 2.3, 2.4, 2.6 & 2.7)
b. hidden skin wound permits entry of air (Case 2.18)
c. surgical procedure permits entry of air (Case 2.44)
2. Following blunt trauma to thoracic wall
a. secondary to pneumomediastinum
b. upper airway tear (Case 2.62)
c. esophageal tear
d. intercostal injury with a pneumothorax
3. Following cervical trauma
a. wound through skin (Case 2.62)
b. wound with tracheal tear (Case 2.70)
c. wound with esophageal tear
4. Gas-forming organism (uncommon)
pneumothorax. Known trauma resulting in air within the
pleural space can be due to a penetrating wound to the tho-
racic wall or to an injury with a blunt instrument to the tho-
rax while the glottis is closed, causing alveolar rupture .
Pneumothorax is one of the most common sequelae to tho-
racic trauma and the types and causes of pneumothorax are
listed in Tables 2.4 and 2.5. The radiographic features of pneu-
mothorax are shown in Table 2.6. A number of technical
problems plus a group of pathologic conditions can make an
erroneous radiographic diagnosis of pneumothorax possible
(Table 2.7).
Table 2.4: Types of pneumothorax
1. Open pneumothorax – pleural pressure less than or equal to atmospheric
pressure (Cases 2.1 & 2.5)
a. thoracic wall wound tearing the thoracic wall pleura
b. referred to as a “sucking pneumothorax”
c. air moves through thoracic wall opening
2. Closed pneumothorax – pleural pressure less than or equal to
atmospheric pressure
a. thoracic wall intact (Cases 2.30 & 2.32)
b. traumatic lung lesion
c. rupture of developmental pulmonary bullae (Cases 2.28, 2.54 & 2.65)
3. Combination of pneumothorax with thoracic wall lesion and lung lesion
(Case 2.75)
4. Tension pneumothorax – pleural pressure greater than or equal to
atmospheric pressure (Cases 2.55, 2.58, 2.59 & 2.75)
a. occurs in either open or closed pneumothorax
b. due to a type of valve mechanism in the lung (thoracic wall) that
I. permits air to enter pleural space during inspiration
II. prevents air from escaping during expiration
5. Secondary to iatrogenic injury to the tracheal/bronchial wall (Cases 2.68
& 2.71)
6. Secondary to thoracocentesis (Case 2.21)
Radiographic features in thoracic trauma 13
2

Table 2.5: Causes of pneumothorax
1. Open pneumothorax – only traumatic (Cases 2.1 & 2.5)
a. puncture wound
b. bite wound
c. gunshot wound
d. trauma with rib fractures
2. Closed pneumothorax – can be post-traumatic or spontaneous in normal
or diseased lung (Cases 2.30 & 2.32)
a. torn visceral pleura with fractured ribs
b. rupture of emphysematous pulmonary bullae
c. tearing of pleural adhesions
d. rupture of pleural blebs/cysts
e. rupture of pulmonary abscess
f. subcutaneous emphysema with mediastinal tear secondary to pneumo-
mediastinum
g. tracheal tear with mediastinal tear secondary to pneumomediastinum
h. main-stem bronchial tear with mediastinal tear secondary to pneumo-
mediastinum
i. esophageal tear with mediastinal tear secondary to pneumo-
mediastinum
3. Tension pneumothorax (Cases 2.59–2.61)
a. with any open or closed pneumothorax
b. presence of a valve or flap-like mechanism
I. in lung
II. in chest wall
4. Unilateral pneumothorax with airtight mediastinum (irrespective of type)
(Cases 2.28 & 2.58)
a. tearing of a fibrinous pleuritis
I. secondary to inflammatory pleuritis
II. secondary to surgery
b. tearing of adhesions between lung lobe and mediastinum
I. secondary to inflammatory pleuritis
II. secondary to surgery
5. Bilateral pneumothorax with fenestrated mediastinum (irrespective of
type) (Cases 2.32, 2.71 & 2.75)
2.1.5.4 Pleural fluid
The radiographic features of pleural effusion are loss of the
cardiac silhouette, loss of the diaphragmatic silhouette, retrac-
tion of the lung lobes, and visualization of the lung fissures
(Table 2.8). The fluid is most often movable and can change in
position remarkably between the DV and VD views. The col-
lection of fluid can be symmetrical or asymmetrical with a
mediastinal shift. While the fluid is usually effusive, it can also
be due to hemorrhage or chylous, secondary to rupture of the
thoracic duct. Thoracocentesis is required to determine the
character of the fluid. The volume of the pleural fluid is in-
creased in patients with chylothorax or in a patient with lung
torsion. Fluid can be trapped around an atelectic lobe and
tends to remain rather fixed in position. Generally, pleural flu-
id is much more readily identified than pleural air, even when
the volume of fluid is minimal. Hemothorax causes a poten-
tially more serious clinical problem and can be secondary to a
wide range of etiologies (Table 2.9). A pleural lesion can be
focal suggesting a chronic lesion with fibrosis (Cases 2.11 &
2.59).
Table 2.6: Radiographic features of pneumothorax
1. Lungs
a. retraction of lung borders from the thoracic wall (Cases 2.28, 2.58
& 2.68)
b. separation of lung borders from diaphragm (Cases 2.1, 2.3, 2.52
& 2.58)
c. increase in lung density (due to partial collapse) (Case 2.54)
d. vascular and bronchial shadows do not extend to the thoracic wall
(Cases 2.28, 2.58 & 2.68)
2. Diaphragm
a. caudal displacement (Cases 2.3 & 2.4)
b. radiolucent zone separates lungs and diaphragm (Cases 2.3 & 2.9)
3. Pleural place
a. radiolucent space between lungs and thoracic wall (Case 2.53)
b. radiolucent fissures between lung lobes
4. Heart
a. separation of cardiac apex from the diaphragm or sternum
(Cases 2.12, 2.15, 2.28, 2.56, 2.58 & 2.65)
b. appears smaller because of increase in size of thoracic cavity
5. Mediastinum
a. lateral shift with unequal distribution of pleural air (Cases 2.32 & 2.59)
6. Thoracic cavity
a. increased width
b. ribs are at right angle to the spine (Case 2.75)
c. increased length of thoracic cavity (Case 2.4)
Table 2.7: Causes of erroneous radiographic diagnosis of pneumo-
thorax
1. Skin folds superimposed over the thorax (Cases 2.9, 2.52, 2.72 & 2.97)
2. Overexposed radiograph making vascular shadows difficult to identify
3. Pulmonary
a. vascular hypoperfusion
b. thromboembolism
c. hyperinflation
d. pulmonary emphysema
4. Pneumomediastinum
5. Subcutaneous emphysema causing superimposed linear shadows
6. Atrophy of the muscles in the thoracic wall
2.1.5.5 Diaphragmatic rupture
The diaphragm is ruptured by a forceful impact on the ab-
domen when the glottis is open and the lungs can be collapsed
permitting the diaphragm to move cranially. Radiography is
performed to determine the presence of diaphragmatic injury
and to localize the rupture site.
Radiographs can show loss of part or all of the diaphragmatic
shadow, absence of part or all of the normal caudal silhouette
of the heart, as well as increased tissue density in the thorax
2

Table 2.8: Radiographic features of pleural fluid (effusive fluid, blood,
or chyle)
1. Lungs
a. retraction and difficulty in visualization of lung borders from thoracic
wall (Cases 2.18 & 2.45)
b. retraction of lung border from spine (Case 2.65)
c. increase in pulmonary fluid density due to pocketed pleural fluid plus
partial collapse of the lungs (Cases 2.3, 2.25 & 2.37)
d. vascular and bronchial shadows do not extend to the thoracic wall
(Cases 2.29 & 2.30)
2. Diaphragm
a. caudal displacement (Cases 2.8 & 2.31)
b. flattened (Cases 2.8, 2.31 & 2.37)
c. fluid causes separation between lungs and diaphragm (Case 2.65)
d. ventral diaphragm silhouettes with pleural pool on DV view (Case 2.21)
e. dorsal crura of the diaphragm silhouettes with pleural pool on VD view
3. Pleural place
a. radiodense fluid
I. between the lungs and thoracic wall (Cases 2.9 & 2.18)
II. between interlobar fissures (Cases 2.21 & 2.30)
III. trapped within mediastinal recesses (Case 2.46)
IV. pocketing (Cases 2.11, 2.14 & 2.22)
b. costodiaphragmatic angles are blunted
c. lung lobe tips are rounded
d. fluid freely movable when comparing
I. DV with VD view (Cases 2.20 & 2.31)
II. right and left lateral views
III. recumbent and erect views
4. Heart
a. cardiac silhouette is elevated from the sternum on the lateral view
(Case 2.40)
b. cardiac shadow silhouettes completely with the pleural pool on DV
view and partially on the lateral view (Cases 2.18 & 2.30)
5. Mediastinum
a. lateral shift if fluid collection is unilateral (Case 2.19)
b. tracheal elevation as mediastinum shifts laterally (Case 2.19)
c. width is
I. widened on DV view
II. more normal width on VD view
6. Thoracic wall
a. ribs are at right angle to spine (Case 2.21)
b. increased size of thoracic cavity (Case 2.44)
Table 2.9: Etiologies of hemothorax
1. Arterial bleeding (high pressure)
a. intercostal arteries
b. tracheobronchial arteries
c. internal thoracic arteries
d. great vessels (uncommon)
2. Venous bleeding (low pressure)
a. pulmonary veins
b. intrathoracic veins
3. Diaphragmatic hernia with prolapsed liver or spleen
4. Abdominal hemorrhage moving through a diaphragmatic tear
5. Hemomediastinum with hemorrhage moving through a torn mediastinum
6. Coagulopathies such as rodenticide poisoning
due to the presence of displaced viscera and secondary pleural
fluid. A shift in the position of the abdominal organs assists in
diagnosis since the liver, spleen, air- or ingesta-filled stomach,
air- or ingesta-filled duodenum, air- or ingesta-filled intestin-
al loops, or air- or fecal-filled colon can all be displaced com-
pletely or partially in a cranial direction into the thoracic cav-
ity. This cranial shift in the position of the abdominal organs
may be only within the abdomen itself or can extend into the
thoracic cavity. In either event, the radiographic appearance
of both the thorax and abdomen varies markedly from normal.
Gastric dilatation of the stomach can occur, if it is lodged
within the thoracic cavity and the pylorus is occluded. A bar-
ium sulfate follow-through study can be performed to demon-
strate the presence of concealed gastrointestinal segments lying
within the thoracic cavity, or to demonstrate a dislocation of
the pyloric antrum and duodenum within the abdomen.
Pleural effusion occurs due to vascular constriction by a ring-
like diaphragmatic tear with an associated entrapment of a
liver lobe, omentum, or small bowel loop(s), or by torsion.
Hemorrhage into the pleural cavity that is secondary to the
trauma can contribute to the volume of pleural fluid.
A congenital/developmental pericardiodiaphragmatic hernia
can be complicated by trauma and is usually characterized by
a dilated pericardial sac, a ventral silhouetting between the
heart shadow and the diaphragm, and possible hernial contents
that all can be recognized on the radiograph (Case 2.51).
The radiographic features that may be found with a traumatic
diaphragmatic hernia are listed in Table 2.10.
2.1.5.6 Damage to lung parenchyma
Abnormalities of the lung parenchyma include pulmonary
contusion (hemorrhage), lung rupture or laceration with for-
mation of pulmonary hematomas, or bullae formation (pneu-
matocele). Most animals with blunt thoracic trauma suffer
some degree of pulmonary contusion, with resulting edema
and hemorrhage in the lung parenchyma. Pulmonary contu-
sion is caused by the rapid compression and subsequent de-
compression of the lungs, and results in a disruption of the
alveolar-capillary integrity, thus causing a diffuse bruising of
the underlying lung with concurrent hemorrhage and edema
of the alveolar and interstitial spaces. These changes cause sev-
eral radiographic patterns to become apparent (Table 2.11).
The most common is a diffuse increase in fluid content with-
in the lung. In addition, pulmonary hematomas can be formed
if localized bleeding is trapped within the pulmonary
parenchyma, forming a fluid-dense pocket (Table 2.12). Pul-
monary cysts are uncommon, but are presumed to represent a
coalescence of ruptured airspaces within the lung parenchyma
and can be seen as localized, spherical radiolucent lesions that
are filled with air or with a combination of air and fluid (Table
2.13).
2

Table 2.10: Radiographic features of traumatic diaphragmatic hernia
1. Features on lateral view
a. diaphragm
I. incomplete visualization of both leaves (Cases 2.43 & 2.45)
II. silhouetting of ventral diaphragm with pleural fluid (Case 2.46)
III. slope is altered (Cases 2.18 & 2.42)
IV. asymmetry between the leaves (Case 2.46)
b. pleural space
I. pleural fluid (Cases 2.18 & 2.50)
i) free-moving
ii) shifts in location when comparing opposite lateral views
II. pleural mass lesions
i) with soft tissue density (liver, spleen, omentum)
ii) containing air and/or ingesta (stomach, small bowel)
(Cases 2.43 & 2.44)
iii) containing air and/or granular material (feces in colon)
(Case 2.41)
c. cardiac silhouette
I. shifted dorsally or cranially (Cases 2.41 & 2.43)
II. cardiac apex not identifiable
d. lung lobes
I. separation of lung lobes from diaphragm due to
i) pleural fluid (Case 2.18)
ii) abdominal viscera
II. separation between lung lobes due to fluid in lobar fissures
(Case 2.21)
III. partial collapse with an increase in fluid density (Cases 2.23 & 2.40)
IV. displacement as indicated by location of the air-filled mainstem
bronchi (Case 2.41)
V. possible torsion made possible because of pleural fluid
e. mediastinum
I. dorsal displacement of trachea (Case 2.41)
II. dorsal displacement of main-stem bronchi
f. thoracic wall
I. fractured ribs, costal arch (Case 2.45)
II. fracture/luxation of the sternebrae
III. fractured spine (Case 2.50)
IV. subcutaneous emphysema
g. abdomen
I. cranial displacement of pyloric antrum and duodenal bulb
(Cases 2.45 & 2.46)
II. gastric dilatation
III. absence of shadow caused by the fat in the falciform ligament
IV. absence or displacement of abdominal viscera (Case 2.50)
2. Features on VD or DV views
a. diaphragm
I. incomplete visualization of both crura (Cases 2.41 & 2.43)
II. asymmetry (Case 2.46)
b. pleural space
I. pleural fluid (Case 2.50)
i) free-moving
ii) shifts in location between VD and DV views (Case 2.20)
II. pleural mass lesions
i) with soft tissue density (liver, spleen, omentum)
ii) containing air and/or ingesta (stomach, small bowel)
(Cases 2.1 & 2.40)
iii) containing air and/or granular material (feces in colon)
(Case 2.41)
c. cardiac silhouette
I. shifted laterally (Cases 2.40, 2.44 & 2.45)
d. lung lobes
I. separation of lung lobes from diaphragm due to
i) pleural fluid (Case 2.18)
II. separation of lung lobes from thoracic wall due to
i) pleural fluid
III. separation between lung lobes due to fluid in the lobar fissures
IV. partial collapse with an increase in fluid density (Cases 2.40 & 2.43)
V. displacement
e. mediastinum
I. lateral displacement of trachea (Case 2.44)
II. lateral displacement of air-filled mainstem bronchi (Case 2.41)
III. generalized mediastinal shift (Case 2.45)
f. thoracic wall
I. fractured ribs
II. subcutaneous emphysema
g. abdomen
I. cranial displacement of pyloric antrum and duodenal bulb
(Case 2.46)
II. gastric dilatation
III. absence of abdominal viscera (Case 2.44)
Atelectasis is an important feature of lung disease and refers to
a diminution in lung lobe volume indicating a partial or total
alveolar air loss (Table 2.14). It may be difficult to differenti-
ate between atelectasis and pneumonia on a radiograph. At-
electasis can be partial or complete depending on the degree
of air and volume lost. Several types of atelectasis are recog-
nized: (1) passive that occurs with uncomplicated pneumo-
thorax or pleural effusion; (2) compressive that occurs if the
intrapleural pressure exceeds the atmospheric pressure, or if a
mass lesion impinges on the surrounding alveoli; (3) obstruc-
tive that occurs as a result of the resorption of the alveolar gas-
es following a total obstruction of a main bronchus; (4) adhe-
sive that alludes to the inability of the alveoli to remain open
because they lack a layer of surfactant; and (5) cicatrization due
to fibrosis. Traumatically induced atelectasis usually results
from the passive or compressive forms.
In the event of a failure of an atelectic lobe to begin to re-
inflate within several days following injury, the possibility of a
more severe injury should be considered. The most likely
complication is post-traumatic pneumonia that results in a
persistent area of increased fluid density within the lobe. The
radiographic features of this type of pneumonia are listed in
Table 2.15.
2

Table 2.11: Radiographic features of lung contusion
1. Infiltrative patterns with
a. lobular, lobar, or multiple lobe distribution (Cases 2.7 & 2.64)
b. no special relationship to hilar region (Cases 2.24 & 2.32)
c. often adjacent to chest wall injury (Cases 2.5 & 2.30)
2. Air-bronchogram pattern indicates more severe lung contusion (Case 2.8)
3. Increased fluid density in the lung because of
a. hemorrhage due to trauma (Cases 2.23 & 2.30)
b. atelectasis secondary to pneumothorax (Case 2.12)
Table 2.12: Radiographic features of a pulmonary hematoma
1. Nodular shape (often tear-drop) (Case 2.38)
2. Size is often 2–3 cm in diameter
3. Number
a. more than one in the same lobe
b. more than one in adjacent lobes
4. Density
a. uniform fluid density (Case 2.37)
b. can have lucent center if blood is replaced with air
5. Margination is sharp
6. Wall thickness is thin, if contrasting air is present
7. Surrounding lung with pulmonary contusion
8. Location
a. tendency for peripheral location in lung lobe (Case 2.37)
b. often subpleural
9. Resolution
a. resolution requires weeks/months
b. can remain as a pulmonary nodule
c. fluid from hematoma can resolve leaving a persistent cavitary lesion
Table 2.13: Radiographic features of traumatic pulmonary cysts
(pneumatoceles or pulmonary bullae)
1. Nodular shape (Case 2.75)
2. Size is often 2–3 cm in diameter (Case 2.28)
3. Number
a. more than one in the same lobe (Case 2.33)
b. more than one in adjacent lobes (Cases 2.54 & 2.75)
4. Density
a. cavitary lesions (Case 2.75)
b. contents within the cyst
I. air filled (most common) (Cases 2.54 & 2.75)
II. fluid filled (Case 2.65)
III. both air and fluid are present
c. air-fluid level identified on horizontal beam radiograph
d. if primarily fluid filled can appear to be a hematoma
5. Margination is sharp (Cases 2.28 & 2.54)
6. Wall thickness is thin, if contrasting air is present (Case 2.33)
7. Surrounding lung with pulmonary contusion (Case 2.19)
8. Resolution
a. can resolve within 3–6 weeks
b. can remain as a cavitary lesion (Case 2.75)
Table 2.14: Radiographic features of atelectasis
1. Definition – diminution in lung lobe volume
2. Clinical importance
a. causes venoarterial shunting
b. can be confused with pneumonia
3. Types
a. passive or relaxation atelectasis (Cases 2.47 & 2.57)
I. small amount of fluid or air accumulation in the pleural space
II. right middle and left cranial lobes are selectively affected
III. contused lobes collapse to a greater degree
IV. airways usually unobstructed
V. usually reversible
b. compression atelectasis (Cases 2.44, 2.54, 2.65 & 2.71)
I. intrapleural pressure exceeds atmospheric pressure
i) tension pneumothorax
ii) large pleural effusions or pleural mass
II. airways usually unobstructed
III. usually reversible
c. obstructive or resorptive atelectasis (Cases 2.55, 2.73, 2.88 & 2.89)
I. total obstruction of a main bronchus or its branches
II. collapse can be central or peripheral
III. important features
i) airway drying
ii) mucous secretion tenacity
iii) mucous ciliary action inhibition
iv) inefficient cough mechanism
v) seen with prolonged lateral recumbency
IV. airless state in lobe can be achieved in 24–36 hours
V. absence of air bronchograms
d. adhesive or nonobstructive atelectasis
I. inability of alveoli to remain open
i) absence of surfactant
II. seen in adult respiratory distress syndrome
III. a problem in trauma to a previously diseased lung
e. cicatrization atelectasis
I. due to chronic fibrosis or scar formation
II. poor prognosis
III. a problem in previously diseased lung
4. Radiographic features (Cases 2.44, 2.54, 2.55 & 2.58)
a. direct changes
I. diminished lung volume
II. altered lung shape
III. displacement of interlobar fissures
IV. vascular rearrangement
V. bronchial rearrangement
b. indirect signs
I. local increase in fluid density
II. mediastinal shift toward side of diminished volume
III. cranial displacement of hemidiaphragm on affected side
IV. compensatory overinflation of unaffected lobes
2

Table 2.15: Radiographic features of post-traumatic pneumonia
(Cases 2.2, 2.10, 2.14, 2.22, 2.26, 2.29, 2.30, 2.37 & 2.38)
(persistent and dependent on nature of injury)
1. Lung
a. increased infiltrative density
b. distribution related to site of lung injury
c. prominent air bronchograms
d. shape of lung lobe remains constant
2. Pleural space features
a. minimal pleural fluid
b. pneumothorax
3. Mediastinal shift minimal toward affected side
4. Thoracic wall features
a. rib fracture
b. subcutaneous emphysema
Table 2.16: Radiographic signs of esophageal disease that can mimic
a dorsocaudal thoracic mass
1. Sliding esophageal hernia (Cases 2.97 & 2.98)
a. stomach
I. partially herniated into the thorax
II. gastric rugal folds within the thorax
III. hernia can contain gastric contents
b. gastroesophageal junction malpositioned cranially within the thorax
c. freely moving hernia
2. Paraesophageal hiatal hernia
a. stomach
I. partially herniated into the mediastinum
II. gastric rugal folds within the thorax
III. positioned alongside the caudal esophagus
IV. hernia can contain ingesta
b. gastroesophageal junction at normal location
3. Gastric invagination into the esophagus
a. dilated esophagus
b. stomach
I. partially herniated into the esophagus
II. gastric rugal folds within the caudal esophagus
c. gastroesophageal junction at normal location
4. Esophageal diverticulum (Case 2.99)
a. dilated esophagus
I. diverticulum can contain ingesta
II. smooth esophageal wall
b. gastroesophageal junction at normal location
c. stomach in normal location
A group of lesions at the gastroesophageal junction can cause
a dorsocaudal thoracic mass that may appear to be pulmonary
in nature (Table 2.16). If large enough and well demarcated,
their relationship with the esophagus may be apparent; how-
ever, if the lesion border is diffuse or surrounded by mediasti-
nal fluid, they must be considered to be pulmonary. Fortu-
nately, the use of a barium sulfate swallow can immediately
prove their relationship with the esophagus and whether they
are trauma related.
2.1.5.7 Mediastinal injury
The mediastinal space contains the heart plus the air-filled tra-
chea, esophagus, major vessels, and lymph nodes. It is divided
into the cranial mediastinal space, the central mediastinal
space, and the caudal mediastinal space. The mediastinum in
the trauma patient can be filled with blood (hemomedi-
astinum) (Table 2.17) and have an increased density, or can be
filled with air (pneumomediastinum) and be radiolucent (Ta-
bles 2.18 and 2.19). Fluid usually migrates cranially causing an
increased width of the mediastinum on the DV or VD views,
and an increased depth on the lateral views. This increased
density is often overlooked on the first radiographic study be-
cause of the presence of superimposed pleural fluid. Mediasti-
nal fluid is often more clearly identified on a second study
made when the patient has failed to recover clinically as would
have been expected from the nature of the trauma, and fol-
lowing the clearing of the pleural fluid, whereby a better eval-
uation of the mediastinum is permitted. Mediastinal air is, in
comparison, more easily identified on a radiograph and tends
to spread throughout the entire space contrasting all of the
mediastinal viscera. A combination of blood and air may be
present (pneumohemomediastinum).
Table 2.17: Radiographic features of hemomediastinum
1. Usually found in the cranial mediastinal space (Cases 2.4 & 2.35)
a. increased fluid density
b. mass-like lesion
c. tracheal elevation
d. increased width and depth of cranial mediastinum
2. Associated bleeding can cause (Cases 2.1, 2.20 & 2.32)
a. pleural hemorrhage
b. pulmonary hemorrhage
c. pericardial hemorrhage
3. Associated free air can cause a pneumohemomediastinum
Table 2.18: Radiographic features of pneumomediastinum
1. Increased visualization of the: (Cases 2.7, 2.12, 2.63 & 2.64)
a. esophagus
b. tracheal wall
c. aorta
d. azygous vein
e. caudal vena cava
f. major cranial vessels
2. Possibly associated with:
a. pneumopericardium
b. retroperitoneal air (Case 2.62)
c. subcutaneous emphysema (Cases 2.7, 2.12, 2.61, 2.63 & 2.65)
d. pneumohemomediastinum
2

Table 2.19: Causes of pneumomediastinum
1. Esophageal damage
2. Tracheal damage
3. Pulmonary injury
a. bronchial rupture
b. alveolar rupture
c. increased alveolar pressure with rupture due to respiratory tract
obstruction
4. After laryngeal surgery
5. Following facial trauma
2.1.5.8 The heart
Injury to the heart and great vessels is uncommon because of
the protection provided by the chest wall and lungs. Traumat-
ic injuries of the cardiovascular system are seldom recognized
radiographically, because when the thoracic trauma is severe
enough to damage these organs, the patient dies quickly. In the
event that such a patient is presented, determination of the
character of the heart is important. A comparison of the ap-
pearance of the heart on both orthogonal radiographic views
is necessary in generating the true character of the heart in
three dimensions. The configuration of the thorax greatly in-
fluences the radiographic appearance of the heart shadow. Pa-
tient positioning also alters the shape of the heart seen on the
radiograph.
A common pattern is seen in the trauma patient with shock
that is characterized by hypovolemia and microcardia, where-
as less often, hemopericardium causes the appearance of a car-
diomegaly. The heart shadow can be separated from the ster-
num due to a pneumothorax. Myocardial contusion can cause
bleeding with a resulting hemothorax, hemopericardium, and
hemomediastinum. Hemothorax is the collection of blood in
the pleural space and appears on both views radiographically
as a typical pleural effusion. Hemopericardium causes an in-
crease in the size of the cardiac silhouette on both views with
a marked rounding of the cardiac shadow. Hemomediastinum
is characterized with difficulty by the increase in mediastinal
fluid.
2.1.5.9 The esophagus
Injury to the esophagus can be the result of foreign bodies,
esophageal stricture, or esophageal rupture. The radiographic
features of esophageal trauma are better identified following
the use of an orally administered barium sulfate suspension
(Table 2.20).
Table 2.20: Radiographic features of esophageal trauma using an
orally administered barium sulfate contrast agent
1. Displacement of the intact esophagus
2. Leakage of contrast agent (Cases 2.91 & 2.95)
a. through esophageal tear into the mediastinum
b. through esophageal tear and mediastinal tear into the pleural space
3. Malformed or dilated esophagus
4. Esophageal foreign body (Cases 2.91, 2.92, 2.93 & 2.99)
a. partial obstruction
b. complete obstruction
5. Esophageal stricture
a. post-traumatic
b. postsurgical esophagitis
2.2 Case presentations
왘
2

2.2.1 Thorax wall injury
Case 2.1
2

Signalment/History: “Muffy” was a shorthaired kitten that
had a history of falling from a second-story window.
Physical examination: The kitten was suffering from
marked respiratory distress. The right thoracic wall palpated as
though there was a soft tissue injury with subcutaneous em-
physema.
Radiographic procedure: Positioning of the kitten was rel-
atively easy and both views of the thorax were made.
Radiographic diagnosis: A minimal separation of the 5th
and 6th
ribs on the right (DV view, arrow) was associated with
generalized subcutaneous emphysema. The retraction of the
lung lobes from the diaphragm on the lateral view was indica-
tive of a pneumothorax. Generalized pulmonary contusion
due to hemorrhage/edema caused increased lung density re-
sulting in a silhouetting of the lung over the heart shadow,
making the heart difficult to identify. Pleural effusion was not
noted. The trachea was normal in position. The diaphragm
was intact.
The stomach was distended and filled with ingesta. Abdomi-
nal contrast was lacking, probably because of the age-depend-
ent absence of peritoneal fat; however, the presence of peri-
toneal fluid was considered.
Differential diagnosis: The radiographic changes were typ-
ical for those associated with thoracic trauma. On the lateral
view, the subcutaneous emphysema caused an uneven fluid
density, which when superimposed over the fat in the falci-
form ligament suggested a peritonitis (arrows).
Treatment/Management: Determination of the origin of
the abnormal pleural air is often important in treatment. The
finding of a rib injury suggested a possible skin wound that
could have caused the subcutaneous emphysema and an open
pneumothorax. However, the pneumothorax could have also
been closed and have resulted from a rupture of the lung due
to the increase in pressure within the lung created as the cat
struck the ground with its glottis closed. The skin lesion was
minimal in this kitten indicating that the latter etiology was
more likely. As a consequence, the treatment was symptomatic
only. “Muffy” recovered nicely.
Thorax wall injury 21
2

Case 2.2
2

Signalment/History: “Snoopy” was a 1-year-old, female
mixed breed dog who had been attacked by two larger dogs.
The thorax was wrapped with a bandage in an effort to reduce
the flow of air into the pleural space and to prevent the obvi-
ously fractured rib ends from further injuring the underlying
lungs.
Physical examination: The severe injury to the right chest
wall was evident and crepitus was apparent on palpation of the
ribs.
Radiographic procedure: Two views of the thorax were
made.
Radiographic diagnosis: Soft tissue swelling along the right
thoracic wall with subcutaneous emphysema was seen over the
badly distorted fractured ribs on the right. The bandaging had
collapsed the subcutaneous space on the right side and forced
most of the subcutaneous air to relocate along the left thoracic
wall. Underlying injury to the right middle lung lobe had
caused its collapse with additional injury to the right caudal
lobe dorsally (black arrows). The cardiac silhouette was shifted
to the right and the left hemidiaphragm was shifted caudally to
permit compensatory hyperinflation of the left lung. Pneu-
mothorax was difficult to detect because of the shadows
caused by the subcutaneous air and the bandage around the
thorax. The diaphragm was intact.
Treatment/Management: The dog was treated with cage
rest and radiographs made three days later showed a decrease
in the subcutaneous emphysema. Collapse of the right middle
lung lobe remained. The right caudal lobe had cleared com-
pletely and was aerating normally.
As an uncomplicated contusion to a lung lobe with only hem-
orrhage and edema should clear within 24 to 48 hours follow-
ing trauma, but whereas the radiographs made on day 3
showed continued right middle lobe collapse, it was assumed
that either the trauma had been more severe than supposed,
bronchial obstruction was present, or a pneumonia was super-
imposed over the injured lung. “Snoopy” was placed on an-
tibiotic therapy because of the possibility of a secondary pneu-
monia in that lung lobe and she improved clinically within the
next few days and was discharged.
Comments: Note how difficult and incomplete the radi-
ographic interpretation would have been if only a single later-
al radiograph of the thorax had been made; having two views
makes the study more complete.
2

Signalment/History: “Chamois” was a 7-year-old, female
Maltese Terrier that had been bitten across the thorax by a
larger dog.
Physical examination: A definite defect associated with the
suspected puncture wound was palpable in the right thoracic
wall with associated subcutaneous emphysema. The lung
fields on the right were quiet on auscultation, while more nor-
mal lungs sounds were heard on the left.
Radiographic procedure: Radiographs were made of the
thorax.
Radiographic diagnosis: Subcutaneous emphysema was
present on the right cranial chest wall plus a wide separation of
the right 7th
and 8th
ribs that indicated a tearing of the inter-
costal muscles (arrow). The increase in fluid density in the
right middle lung lobe plus the loss in volume suggested both
contusion and atelectasis. The right caudal lung lobes as well
as the left lung appeared to be well inflated. A portion of the
right scapula created an apparent region of increased fluid
density in the region of the right cranial lobe. Retraction of
the caudal lung lobes from the diaphragm on the lateral view
indicated a pneumothorax. Minimal pleural effusion was evi-
dent on the right. The diaphragm was intact with the left
hemidiaphragm more caudal in position. Identification of the
spleen confirmed the absence of adjacent peritoneal fluid.
Treatment/Management: “Chamois” was treated conserv-
atively and recovered.
Comments: The trauma was more of a puncture wound sug-
gesting the possibility of severe injury to the underlying lung
that could require a longer time in healing. Pocketing of pleu-
ral fluid often occurs around partially collapsed lung lobes.
Case 2.3
2

Case 2.4
2

Signalment/History: “Peppy”, a 2-year-old, male Pekin-
gese, had been found by his owner in respiratory distress sev-
eral hours earlier. The owner assumed another dog had at-
tacked him.
Physical examination: Physical examination was difficult to
conduct because of pain. Subcutaneous emphysema was pal-
pated along the left thoracic wall, along with an obvious dis-
placement of the mid-thoracic ribs.
Radiographic procedure: It was difficult to position the
dog for the DV view because of the soft tissue injury around
the left shoulder.
Radiographic diagnosis: Severe thoracic wall injury was
evident with multiple fractures of the left 5th
, 6th
, 7th
, and 8th
ribs resulting in a flail chest. Generalized subcutaneous em-
physema was present. The left lung lobes had a loss in volume
plus an increased fluid density, probably resulting from a com-
bination of pulmonary contusion and atelectasis. The right
lung lobes had only a minimal increase in fluid density from
the passive atelectasis caused by the pneumothorax (white ar-
rows). The collapse of the left lobes and severe injury to the
chest wall probably resulted in the pleural air shifting into the
right hemithorax. The left lung collapse had resulted in a min-
imal mediastinal shift to the left. The cranial mediastinum was
widened at the level of the first ribs suggesting a hemomedi-
astinum (black arrows). No pleural fluid could be identified,
although it was difficult to make any judgment of possible flu-
id in the left hemithorax. The cardiac silhouette appeared sep-
arated from the sternum because of the mediastinal shift. The
caudal displacement of the right hemidiaphragm was expect-
ed with the lung changes noted.
Treatment/Management: The patient was not left for
treatment.
Comments: A pneumothorax on the side opposite to the
trauma is not very common and indicates the presence of a
fenestrated mediastinum. The origin of the subcutaneous air is
probably associated with the puncture wound although a lung
lobe could also have been lacerated. A skin laceration, espe-
cially in the axillary region, can function as a “pump” activat-
ed by movement of the forelimb thereby filling the subcuta-
neous space with air.
The position of the mediastinum in this patient is affected by:
(1) atelectasis on the right, (2) pneumothorax on the right, and
(3) lung injury with lobar collapse on the left. The free pleu-
ral air contrasts with the aorta and esophagus on the lateral
view making them more visible.
Note that the lateral view is oblique as shown by the location
of the rib ends dorsally and ventrally. Also, the shoulder joints
are not superimposed. Oblique positioning of this type can be
easily corrected by the placement of small sponge wedges un-
der the sternum and under the ventral portion of the ab-
domen.
2

Case 2.5
2

Signalment/History: “Rax”, a 9-year-old, male DSH cat,
had been attacked by a dog 10 days previously. Following the
trauma, he had run away and had been missing for the inter-
vening 10 days. He had only returned home on the day of
presentation.
Physical examination: Palpation of the thorax indicated
marked abnormality in the region of the sternum with severe
soft tissue swelling. The cat was dyspneic.
Radiographic procedure: Thoracic radiographs were made
with the background knowledge that they were probably
made 10 days after the injury.
Radiographic diagnosis (day 10): Injury to the sternum
had resulted in a ventral and cranial displacement of sternebrae
6, 7, and 8 (top left). The xiphoid process remained in a near-
normal position. Injury to the thoracic wall on the left had
caused a flail chest with multiple fractures of left ribs 7–10,
which were characterized by fragment displacement and se-
vere injury to the thoracic musculature (DV view). Subcuta-
neous emphysema was seen. The left crus of the diaphragm
was shifted cranially, but appeared to be intact. The left lung
lobes had an increased water density indicating contusion and
atelectasis to the caudal half of the cranial and caudal lobes.
Treatment/Management: This case was unusual since the
history suggested that the cat had been injured 10 days prior to
presentation for treatment. It illustrates how survival can be
achieved if one lung remains functional despite the open
pneumothorax and severe injury to one chest wall.
Additional radiographs were made nine days later (top right)
following surgical repair of the flail chest by the placement of
an external splint around the chest wall, which permitted a lat-
eral “fixation” of the larger rib fragments to the external de-
vice.
It is remarkable that “Rax” continued to improve clinically
and was eventually released.
2

Case 2.6
2

Signalment/History: “Blimp”, an obese, 5-year-old, male
DSH cat, was dyspneic and had a puncture wound in the right
thorax and subcutaneous emphysema on the left.
Physical examination: The obesity of this cat made it al-
most impossible to auscultate the lungs or to learn of the status
of the patient by physical examination.
thorax with the hope of learning more of the origin of the
puncture wound and its severity. Two right lateral views were
made, one on greater inspiration.
Radiographic diagnosis: A marked infiltrative pattern
within the lung lobes was located primarily in the middle and
caudal lobes on the right (DV). The pattern was assumed to be
interstitial since an air-bronchogram pattern could not be
identified. Subcutaneous emphysema was more severe on the
left and a single metallic pellet lay in the soft tissue at the lev-
el of the 9th
rib on the left. Fracture of the 7th
rib on the right
with a small metallic fragment adjacent to the fracture site
suggested the shot had passed through the thorax. The di-
aphragm was intact. Pleural fluid was difficult to evaluate be-
cause of the cat’s obesity.
Treatment/Management: The fracture plus identification
of the single pellet indicated a gunshot wound resulting from
a high-pressure airgun. “Blimp” recovered and returned to his
life of leisure.
Comments: The cat’s obesity had resulted in the deposition
of fat adjacent to the parietal pleura making the detection of
minimal pleural fluid impossible. Lack of inspiration in this
obese patient made determination of the severity of lung in-
jury impossible.
2

Case 2.7
Signalment/History: “Grenigo” was a 2-year-old, male
DLH cat who had been hit by a car 12 hours earlier.
Physical examination: The cat was dyspneic and unable to
stand. He did not seem to be able to move his pelvic limbs.
Deep pain was evident in the pelvic limbs.
thorax and of the lumbar spine and pelvis.
Radiographic diagnosis (thorax): Extensive subcutaneous
emphysema was located primarily on the left. The 5th rib on
the left was fractured and the separation of the ribs indicated
intercostal muscle tearing (white arrows). Widening of the
space between sternebrae 3 and 4 suggested a luxation. Exten-
sive pulmonary contusion was most severe on the right, but
also affected the left cranial lobe. Pneumothorax was princi-
pally on the left and minimal. Signs of pneumomediastinum
were prominent.
2

Radiographic diagnosis (lumbar spine): A compression
fracture involved the body of L6 with collapse of the L5–6
disc space (arrow). Bony fragments appeared to be driven dor-
sally into the spinal canal. Both hip joints were unstable prob-
ably due to hip dysplasia.
Treatment/Management: “Grenigo” was treated conserv-
atively. The pulmonary contusion regressed rather quickly. By
maintaining a strict control on movement, the vertebral frac-
ture healed in two weeks permitting him to eventually walk
almost normally.
2

Case 2.8
2

Signalment/History: “Asta”, a 6-month-old, female Ger-
man Shepherd puppy, had been struck by a car one hour pri-
or to presentation for treatment.
Physical examination: She was unable to rise to a standing
position. She had no pain sensation in the right forelimb and
minimal voluntary movements in the left forelimb.
thorax as a part of a clinical work-up for a trauma patient.
Radiographic diagnosis: An increase in fluid density was
noted in the cranial lung lobes. It was more prominent on the
right side, probably indicating pulmonary contusion. It was
difficult to evaluate the width of the mediastinum on the VD
view, but the presence of mediastinal thickening due to hem-
orrhage was considered. A fracture of the first rib on the left
was identified. Air-bronchograms in the left cranial lobe
(arrow) indicated injury to that lung also.
The injury in the axillary region in a patient with neurologic
deficits in a forelimb suggested that the soft tissue injury was
more important than the minimal lung and rib lesions.
Treatment/Management: Both a brachial plexus injury and
pelvic injury were suspected. The cervico-thoracic injury was
partially confirmed by identification of the rib fracture. Addi-
tional radiographic studies of the thoracic inlet region were
made using a more penetrating x-ray beam, but added no new
information. Pelvic radiographs were made and showed only a
developmental transitional lumbosacral segment with an asso-
ciated malposition of the pelvis and did not indicate a recent
fracture.
“Asta” was diagnosed with an avulsion type injury to the
brachial plexus and did not recover the use of her forelimb.
Comments: Cranial mediastinal width is difficult to detect in
a case such as this and mediastinal hemorrhage was not con-
firmed.
Because of the large size of the dog, an error was made in not
including the entire diaphragm on the DV radiograph. The
marked caudal displacement of the left hemidiaphragm was
only suspected on the DV view. On the lateral view, the shad-
ow of the dorsal crura on the left was positioned caudally.
2

Case 2.9
Signalment/History: “Ginger” was an obese, 10-year-old,
female Golden Retriever, who had been hit by a car several
hours earlier and was presented with a flail chest.
Physical examination: Palpation of the thorax indicated se-
vere injury to the ribs on the right. A soft tissue mass was ev-
ident in the inguinal region, but this was not thought impor-
tant at the time.
Radiographic procedure: Initially on day 1, only thoracic
radiographs were made due to the condition of the patient.
But because of the caudal location of the thoracic trauma, in-
jury to the liver, pancreas, and gall bladder needed to be con-
sidered and abdominal studies were made as soon as the patient
was stabilized.
Radiographic diagnosis (day 1, thorax): Multiple frac-
tures of the 9th–12th ribs on the right were noted with frag-
ment displacement (flail chest), causing a marked deformity of
the caudal portion of the right thoracic wall. Loculated pleu-
ral fluid, probably a hemothorax, was present in the caudal
right hemithorax. This was associated with a volume loss
caused by the caudal lobe atelectasis. The pulmonary vessels
were small indicating shock. The apparent slight mediastinal
shift to the left was thought to be the result of spinal curvature
due to positioning and not due to trauma. A pneumothorax
was expected in association with the chest wall injury, but a
pattern of pleural air was difficult to identify. A small pattern
of air separated the left caudal lung lobe from the chest wall
and the diaphragm, but the volume was much less than antic-
2
Day 1

ipated considering the nature of the injury. The diaphragm
was intact with the ventral portion more cranial in position
than normal. A minimal amount of peritoneal fluid, probably
hemorrhage, caused a reduced contrast in the abdomen.
Radiographic diagnosis (day 3, abdomen): Intestinal
loops were noted within a right inguinal hernia. Loss of peri-
toneal shadows suggested the presence of peritoneal fluid. Liv-
er, gastric gas bubble, and spleen were identified in their nor-
mal positions. The diaphragm was intact. Failure to identify
the urinary bladder was thought to be an important finding.
Differential diagnosis: The distention of the single small
bowel loop could mean: (1) an obstructive lesion associated
with the hernia, (2) a paralytic ileus associated with damage to
the blood supply to a solitary loop, or (3) a paralytic ileus as-
sociated with spillage of urine into the peritoneal cavity. This
question was resolved at the time of abdominal surgery.
Treatment/Management: The inguinal hernia was re-
paired. The associated bowel loop was found to have a good
blood supply and not to be torsed. “Ginger” was discharged
with a persistent chest wall deformity and the possibility of be-
ing a “chronic respiratory cripple”.
Comments: “Ginger” is an example of the importance of
making both thoracic and abdominal radiographic studies rec-
ognizing that this technique can be of immediate value in the
evaluation of the entire patient.
2
Day 3

Case 2.10
Signalment/History: “Buster” was a 1-year-old, male
Golden Retriever with a history of chronic cough.
Physical examination: The examination did not contribute
to an understanding of the clinical signs. There was no histo-
ry of trauma that might have preceded the cough.
Radiographic procedure: Multiple views were made of the
thorax.
Radiographic diagnosis: The injury to the right thoracic
wall was long-standing with malunion rib fractures and thick-
ened pleural shadows indicative of pleural scaring. The cardiac
shift toward the site of injury suggested pleural adhesions with
atelectasis. The lesion was not identified on the lateral view.
Treatment/Management: The post-traumatic changes
caused a failure of normal expansion of the right middle lobe,
a probable defect in the ciliary clearing mechanism, and a pos-
sible chronic pneumonia. Three separate DV radiographs were
made to insure that the apparent shift in position of the medi-
astinum was not due to improper positioning of the patient
during radiography. The apparent cardiomegaly may have
been real or the result of the heart’s malposition.
Treatment was limited to the purely symptomatic.
2

Case 2.11
Signalment/History: “Quake” was an 8-year-old, male
Schnauzer mixed-breed with a history of a left-sided thoracic
mass thought to be secondary to a bite wound.
Physical examination: No evidence of soft tissue injury was
noted. The soft tissue mass was firm, not warm, and not fluc-
tuant.
Radiographic procedure: The intensity of the radiograph-
ic beam used for the thoracic studies was increased to permit a
better evaluation of the thoracic wall.
Radiographic diagnosis: A concave defect in the thoracic
wall on the left (arrows) was associated with an increase in the
width of the extra-thoracic musculature. Focal pleural thick-
ening or trapped pleural fluid lay adjacent to the defect. No rib
fractures were noted. The cardiac and pulmonary structures
were normal. The lateral view did not contribute to the eval-
uation of the thoracic wall lesion.
Differential diagnosis: The differential diagnosis of a flat-
tened, focal, pleural thickening in the absence of rib lesions in-
cludes: (1) inflammatory pleuritis that can be acute or chron-
ic, and active or quiescent, (2) a soft tissue tumor invading
from the extra thoracic region such as a fibrosarcoma, (3) a
pleural tumor such as a mesothelioma, or (4) chronic chest wall
injury.
2
At presentation

Treatment/Management: Surgical exploration resulted in
the removal of a plant awn that had partially penetrated into
the thoracic cavity. A follow-up study made three months
later showed only a persistent pleural thickening as a conse-
quence of the infection and the surgery.
2
Month 3

Case 2.12
Signalment/History: “Sandy”, a 5-year-old, male Queens-
land Heeler, had been hit by a car 24 hours earlier.
Physical examination: The examination was difficult be-
cause of the obtunded status of the dog. Abnormalities in the
left chest wall could be palpated.
Radiographic diagnosis (referral radiographs): Referral
radiographs showed a massive pneumothorax with extensive
separation of the cardiac silhouette away from the sternum.
The lung lobes on the right and the cranial lobe on the left
showed pulmonary contusion. Rib fractures were present on
the left. A pneumoperitoneum was suspected. The status of
the diaphragm was uncertain, especially in the region of the
esophageal hiatus. Metallic shotgun pellets were noted, but
were thought to be incidental.
2
Referral radiographs

Radiographic diagnosis (day 2): The pneumothorax was
persistent, however, the pulmonary contusion/atelectasis was
less than in the referral radiographs. Pneumomediastinum
could now be seen. The subcutaneous emphysema on the left
was still evident. The fractured ribs showed further separation
between the 5th
and 6th
ribs on the left. The diaphragm
appeared intact on this study. The tip of a thoracic tube on the
right lay at the level of the 9th
rib (DV view, arrow).
왘왘
2
Day 2

Radiographic diagnosis (day 4): The status of the patient
improved after being on the pleura-vac for two days. The
pneumothorax decreased and the right lung re-inflated. The
pneumomediastinum was still evident and the chest wall injury
remained unchanged. A chest tube remained in position on
the left side.
Treatment/Management: The pneumothorax recurred fol-
lowing removal of the thoracic tube on day 4, thereby delay-
ing recovery. The appearance of the lungs and the extensive
pneumothorax suggested little functional lung tissue at the
time of the first study. The radiographic appearance is a warn-
ing that the lung injury was more severe than normally seen
with the usual blunt trauma. The pneumomediastinum was
probably present on the first study as indicated by the gas
within the soft tissues at the thoracic inlet. This also is a possi-
ble indication of injury to either a main stem bronchus or the
trachea and is indicative of a probably prolonged recovery.
2
Day 4

Case 2.13
Signalment/History: “Tom” was a 1-year-old, male DLH
cat with a malformed thoracic cavity thought to have oc-
curred following an accident. The owner was concerned be-
cause of the “strange shape of the chest”.
Physical examination: The abnormality in the sternum was
easily palpated; however, no pain or soft tissue swelling was
noted. Heart sounds were much more prominent on the left
side.
thorax.
Radiographic diagnosis: A congenital anomaly of the ster-
num had caused the xiphoid process to be angled dorsally and
to the right (arrows). As a result, the apex of the heart was
shifted to the left against the thoracic wall. The lung fields
were normal. The diaphragm was intact, but was shifted cau-
dally. The liver shadow was shifted ventrally and caudally.
Treatment/Management: The congenital anomaly had
caused marked changes in the conformation of the thorax
without markedly affecting the function of either the lungs or
heart. As a consequence, no treatment was considered.
2

2.2.2 Paracostal hernia
Case 2.14
2
Day 1
Signalment/History: “Baby” was a 7-month-old, male
DSH cat who had been missing from home for several days.
Physical examination: He was depressed, dyspneic, and in
shock.
Radiographic procedure: Lateral views of the whole body
were made.
Radiographic diagnosis (day 1, whole body, lateral
view): A large soft tissue mass lay ventral to the xiphoid
process on the right side. It contained air-filled bowel loops
plus disseminated air indicative of subcutaneous emphysema.
The abdominal wall and ventral liver border could not be
identified suggesting the presence of peritoneal fluid. Adjacent
to the diaphragm was an area of increased fluid density with-
in the dorsal part of the caudal lung lobes possibly due to ei-
ther a pulmonary lesion such as hemorrhage or even a lesion
affecting the gastroesophageal junction.

Radiographic diagnosis (day 2, DV and lateral views):
Radiographs made two days later continued to show the ex-
tra-thoracic mass, but without the presence of air-filled bow-
el loops. Diffuse air again suggested subcutaneous emphysema
from a puncture wound in the skin. The DV view confirmed
a pulmonary lesion and located it in the caudal lobe on the
right. The continued presence of the pulmonary lesions sug-
gested the cause was more than just a contusion. Disruption of
the 10th and 11th ribs on the left indicated the nature of the in-
jury as a probable bite wound with injury on both sides of the
thorax. Pleural fluid pocketed around the dorsal segment of
the right caudal lobe suggested a failure of that lobe to fully in-
flate. The possibility of peritoneal fluid remained. The ab-
sence of bowel loops in the hernial sac provided an excuse to
postpone surgery.
Treatment/Management: After three days in the clinic
during which antibiotics were used to treat the unknown
cause of an elevated WBC count, “Baby” collapsed and emer-
gency surgery identified rents in the stomach and a bruised
ileum. A tear in the dorsal diaphragm was identified without
herniation of abdominal contents. Necrotic omentum was
noted in the paracostal hernia. Peritonitis and pneumonia
were evident at necropsy two days later.
Comments: It was thought that this patient had been treated
rather too conservatively in the face of the radiographic and
clinical findings, which suggested the presence of a more se-
vere clinical situation.
Paracostal hernia 47
2
Day 2

Case 2.15
2

Signalment/History: A male, mixed-breed puppy was
found lying by the roadside and was brought to the clinic for
treatment.
Physical examination:A soft tissue mass was palpable on the
right abdominal wall. The physical examination was limited.
Radiographic procedure: Abdominal radiographs were
made.
Radiographic diagnosis: Air-filled small bowel loops were
displaced laterally into a soft tissue pocket along the right ab-
dominal wall. The bowel loops within the hernia did not ap-
pear distended. The 11th
and 12th
ribs on the right were frac-
tured. An increase in fluid density of the caudal lung lobes was
noted as well as a pneumothorax, which had resulted in sepa-
ration of the cardiac silhouette from the sternum. Subcuta-
neous emphysema was present over the caudal abdomen. End-
plate fractures of the bodies of T13 and L2 helped to explain
the extreme pain exhibited by the puppy.
Treatment/Management: A major problem in diagnosis in
this puppy was to distinguish whether the air pockets located
in the hernial sac were within bowel loops or represented free
subcutaneous air that had pocketed. The tendency for the air
to be defined into well-marginated patterns suggested that it
was more likely to be lying within bowel loops.
The hernia was repaired, the bowel loops replaced within the
peritoneal cavity, and the puppy closely confined until the
fractures had healed.
2

Case 2.16
2

Signalment/History: A young, male Chihuahua had been
found by a friend of the owner laying on its side and breath-
ing with great difficulty after being attacked by larger dogs.
He was brought to the clinic.
Physical examination: A large soft tissue mass could be pal-
pated on the left body wall.
caudal portion of the body.
Radiographic diagnosis: Incomplete fractures of the last
ribs on the left were noted with a costovertebral luxation of
the last two ribs. The underlying lungs appeared normal. Her-
niation of air-filled bowel loops, spleen, mesenteric fat, and a
part of the stomach filled the paracostal hernial sac on the left.
A soft tissue mass just cranial to the bowel loops had an uneven
fluid density and was thought to be hemorrhage (hematoma).
The small bowel loops were air-filled and distended suggest-
ing a paralytic ileus.
The displaced gastric shadow had the pylorus on the left side.
Although the fundus was displaced cranially, it was thought
not to be herniated through a diaphragmatic tear. Uniform
fluid density within the cranial abdomen suggested a focal
peritoneal hemorrhage or peritonitis.
Note that the trauma did not affect the underlying lungs and
had not caused a generalized peritoneal hemorrhage or peri-
tonitis. The distention of the stomach with air suggested a py-
loric stenosis.
Treatment/Management: At surgery, the gut was partially
twisted on its mesentery with secondary necrosis. No tear in
the diaphragm could be found. The dog was discharged after
surgery.
2

2.2.3 Pleural fluid
Case 2.17
Signalment/History: This mature, female DSH cat was a
stray that was found by the new owner to have a prominent
swelling on the right side of her body.
Physical examination: The prominent soft tissue mass was
easily palpable and the contents could be readily compressed.
Radiographic procedure: Whole body radiographs were
made.
Radiographic diagnosis: The soft tissue swelling was cen-
tered around the last ribs on the right and contained discrete-
ly outlined air-filled structures thought to be bowel loops. The
stomach was enlarged and fluid-filled suggesting the possibili-
ty of a pyloric obstruction. No injury to the chest wall was
seen except for injury to the last asternal ribs on the right. The
diaphragm was intact. The lungs appeared normal. No pleural
fluid was noted.
Treatment/Management: The owner refused treatment of
the paracostal hernia and the cat was lost to follow-up. The
bowel loops were not distended and the possibility of a bowel
obstruction was considered minimal; still, the owners were ad-
vised that surgical repair was recommended.
2

Case 2.18
Signalment/History: “Olive” was a 2-year-old, female Old
English Sheepdog with a history of being unable to breathe
when placed in dorsal recumbency. She became acutely
dyspneic when positioned on her back and the owners
believed she had been shot by the neighbors.
Radiographic procedure: Studies of the thorax were or-
dered because of the history of dyspnea.
Radiographic diagnosis: A massive pleural effusion was
present, characterized by retraction of the lung lobe margins
from the thoracic wall. The cardiac silhouette was difficult to
evaluate, but was probably normal in size, shape, and position.
The lung fields were also difficult to evaluate, but the cranial
main-stem bronchi were folded caudally suggesting the pres-
ence of a cranial intrathoracic mass. The diaphragmatic shad-
ows were difficult to assess, but they appeared to be located
caudally and were flattened. No evidence of chest wall injury
was noted. A severe congenital sternal anomaly resulted in
only 5 or 6 segments being present.
Treatment/Management: Treatment was medical and the
possibility of lung lobe torsion was not proven.
Pleural fluid 53
2

Case 2.19
Signalment/History: “August” was a 4-month-old, male
Australian Shepherd who had been in a dogfight two days pre-
viously.
Physical examination: An injury to the left thoracic wall
could be palpated. It was possible to insert several fingers be-
tween the displaced ribs.
thorax.
Radiographic diagnosis (day 1): Disruption of the caudal
ribs on the left was associated with intercostal muscle tearing,
soft tissue swelling in the thoracic wall, and minimal subcuta-
neous emphysema; all of which were indicative of a massive
puncture wound. Extensive pleural bleeding in the left
hemithorax and collapse of the underlying lung lobes resulted
in a mediastinal shift to the right. Note the cavitary lesion in
the left caudal lobe that represents a traumatic pneumatocele.
The tracheal shadow was elevated as a result of the heart mov-
ing into the right hemithorax. The presence of hemorrhage
within the mediastinum could not be evaluated.
2
Day 1

Radiographic diagnosis (day 2, DV view only): Radio-
graphs done the next day showed a lesser amount of pleural
fluid with an increase in the aeration of the left lung lobes.
Radiographic diagnosis (day 4, DV view only): Radio-
graphs taken two days later showed a worsening of the condi-
tion with a marked increase in the amount of pleural fluid
causing a more extensive mediastinal shift to the right. Note
the shifting of the carina (arrow). The left lung did not appear
to contain any air at this time.
왘왘
Pleural fluid 55
2
Day 2 Day 4

Treatment/Management: Surgery to remove the hemor-
rhaging left caudal lung lobe was performed on day 4. Radio-
graphs made on day 10 showed a partial aeration of the re-
maining lung lobes on the left. The left hemidiaphragm was
shifted cranially and the accessory lobe had shifted into the left
hemithorax. All of these changes resulted in a minimal medi-
astinal shift to the left. The rib injuries were not treated.
Detection of a traumatic pneumatocele indicated a more se-
vere injury to the lung than expected with a typical blunt trau-
ma, and suggested that lobectomy might be required to stop
the hemorrhage.
The possibility of abdominal organ injury was considered be-
cause of the caudal location of the injury; however, treatment
for an abdominal injury was not required.
2
Day 10

Case 2.20
Signalment/History: “Duke” was a 7-year-old, male Ger-
man Shepherd with a history of having sustaining stab wounds
to the thorax three days earlier. He had been given emergency
treatment and was referred with a history of hemothorax that
had been increasing in volume as shown by daily thoracic ra-
diographs.
Physical examination: He was thought to be in DIC at the
time of admission to the hospital and was having PVCs.
Radiographic procedure:The thoracic study included both
VD and DV views.
Radiographic diagnosis: The pleural fluid was massive and
was freely movable when the DV and VD views were com-
pared. It was suspected to be hemorrhage because of the his-
tory. The fluid pooled around the right middle lobe and the
caudal portion of the left cranial lobe, indicating some degree
of atelectasis. Mediastinal widening was suspected to be the
result of a hemomediastinum with the possibility of organized
blood clots within that structure. This was more evident on
the VD view.
A diffuse pulmonary pattern was noted throughout the lungs
without evidence of an air-bronchogram pattern. The cardiac
silhouette was identified and thought to be within normal lim-
its; however, the examination was compromised by the pres-
ence of pleural fluid. The failure to identify a displacement of
the lung lobes or mediastinum suggested an absence of any
pleural masses. The minimal soft tissue thickening noted on
the left thoracic wall was assumed to be secondary to the trau-
ma.
No evidence of peritoneal fluid was noted. Minimal spondy-
losis deformans was evident in the caudal thoracic spine.
Small circular shadows on the lateral view are attachments for
the leads from the EKG machine.
Pleural fluid 57
2
왘왘

2
Day 1

Radiographic diagnosis (day 25): Resolution of the pleu-
ral fluid was remarkable along with the identification of nor-
mal pulmonary bronchovascular markings.
Treatment/Management: Stab wounds are a different form
of trauma from the more common blunt chest trauma result-
ing from automobile accidents. The absence of alveolar fluid
and the presence of pleural fluid instead suggested a puncture-
type wound to the lungs. An important aspect in this case
could be seen on comparison of the DV and VD views of the
first study that showed not only the amount of pleural fluid
and how freely it moved, but the relatively uninjured lung
lobes as well. The diaphragm was not visualized on the DV
view but was thought to be normal on the VD projection.
If the injury was truly a “stab wound” resulting in pleural and
mediastinal hemorrhage, why was not a pneumothorax pres-
ent as well? A thoracic wall injury secondary to a stab wound
probably closes immediately and does not permit air to enter
the thoracic cavity. In this case, it seems possible that the lung
lobes had not been injured and the bleeding had resulted from
some other vascular injury.
The presence of secondary pneumonia is always difficult to
determine in trauma cases with lung lobe contusion and/or at-
electasis. That was not a problem in this dog. “Duke” recov-
ered completely following conservative treatment and re-
turned to work on the police force.
Pleural fluid 59
2
Day 25

Case 2.21
Signalment/History: “Roy” was a 4-year-old, male English
Pointer with a history of chronic dyspnea. Small quantities of
purulent pleural fluid had been aspirated in the past. A grass
awn had been removed from the thoracic wall 1 year previ-
ously.
Physical examination: Lung sounds could not be auscultat-
ed and the heart sounds were muffled. The patient was dys-
pneic and slow to move.
Radiographic procedure:Thoracic radiographs were made.
Radiographic diagnosis (day 1): Massive pleural fluid was
seen on both views and prevented evaluation of the lung lobes.
Pleural fluid had infiltrated into the fissures between the lung
lobes. The bronchi and pulmonary vessels could not be seen
completely, but they were thought to be in their normal posi-
tion, which ruled out any pulmonary mass lesions. The di-
aphragm could not be completely identified ventrally. The
thorax was widely expanded.
2
Day 1

Radiographic procedure (day 2): Radiographs were made
on day 2 following the removal of 675 ml of purulent pleural
fluid. The lung lobes could be better evaluated A fluid-dense
mass was noted within the accessory lobe, which silhouetted
with the heart shadow and the diaphragm. A minimal pneu-
mothorax probably secondary to the placement of the needle
for aspiration of the pleural fluid was present. The normal po-
sition of the gastric air bubble helped to rule out a diaphrag-
matic hernia.
Treatment/Management: Chronic trauma was considered
in this patient, but the nature of the pleural fluid was strongly
suggestive of an inflammatory lesion. The geographical loca-
tion in which the dog lived had grass awns. This fact, plus the
past history of grass awn migration into the thoracic wall, sug-
gested that abscessation within the accessory lobe was the pri-
mary diagnosis. The dog was operated and the affected lobe
removed. A grass awn was identified as the cause of the abscess.
Recovery of the patient was difficult because of the chronic
infection.
Pleural fluid 61
2
Day 2

Case 2.22
2
Day 3

Signalment/History: “Kato” was a 4-year-old, male Brit-
tany presented two days after an accidental gunshot wound in
the chest inflicted by his owner.
Physical examination: He was quiet, alert, with pale mu-
cous membranes, and afebrile. Increased sounds could be heard
in the left lung.
thorax.
Radiographic diagnosis (day 3): Extensive pleural fluid
was present. It was movable as indicated by comparison of the
DV and VD views. A pulmonary infiltration was suspected in
the caudal aspect of the left cranial lobe, but this was difficult
to prove because of the pleural fluid that had pocketed in that
region. The width of the mediastinum was thought to be nor-
mal. No evidence of pneumothorax was noted.
Two metallic pellets were located within the thorax on the
right side ventrally. On comparison of the DV and VD views,
they appeared to be fixed in position. It was assumed that the
fluid was the result of hemorrhage secondary to the gunshot
wound, but the injury to the lung was difficult to assess.
Radiographic diagnosis (day 16): A persistent mild pul-
monary infiltrative pattern remained in the caudal half of the
left cranial lung lobe with the probability that pleural fluid had
remained pocketed around that lobe. The two metallic pellets
could still be identified; however, one had moved cranially
and was thought lie within the cardiac silhouette, most prob-
ably within the pericardial sac.
Treatment/Management: The location of the pellet re-
mained questionable. The cranial metallic pellet was observed
fluoroscopically to move dependent on the heart beat and was
therefore determined to be located within the pericardial sac.
The pulmonary effusion was slow to clear suggesting either
secondary pneumonia or severe pulmonary damage. The dog
was discharged without treatment of the metallic foreign
body. “Kato” was only four years old and should have recov-
ered to have healthy lungs without any residual disease.
Pleural fluid 63
2
Day 16

2.2.4 Lung injury
Case 2.23
Signalment/History: “Gypsy”, a 5-year-old, female Brit-
tany, had been hit by a car.
Physical examination: On physical examination, she had
increased lung sounds and dyspnea.
Radiographic procedure: Routine studies of the thorax
were performed.
Radiographic diagnosis: Pulmonary contusions in the left
lung lobes caused an increase in fluid density that was most
prominent in the left caudal lobe, and was most likely the
result of pulmonary hemorrhage. Minimal pleural fluid was
noted and no pleural air could be identified. The chest wall,
diaphragm, mediastinum, heart, and great vessels were all nor-
mal.
Treatment/Management: While the owners were greatly
concerned because they had witnessed the trauma to the dog,
the radiographic findings suggest that the injury was rather mi-
nor. The dog was released after two days in the hospital fol-
lowing conservative therapy.
2

Case 2.24
Signalment/History: “Faswa” was a 5-year-old, female
Border Collie who had been struck by a car two days previ-
ously.
Physical examination: As she had remained dyspneic and
was not moving normally, “Faswa” was brought to the clinic
for examination.
Radiographic procedure:Thoracic radiographs were made.
Radiographic diagnosis: Minimal subcutaneous emphyse-
ma was present on the right side with an incomplete fracture
of the 8th
rib. An old malunion fracture of the 9th
rib was pres-
ent on the right. The diaphragm was intact. A small amount
of pleural fluid was present, but the major finding was the
atelectic right middle lung lobe with a minimal contusion of
the right caudal lobe.
Treatment/Management: The right middle lung lobe is
comparatively small and yet has a large surface area. If injured
or diseased, it can be quickly collapsed by the adjacent aerat-
ing lobes leading to the term “right middle lobe syndrome”.
Notice that this lobe is superimposed over the cardiac silhou-
ette on the lateral view, so the increase in fluid density cannot
be appreciated on that view. A small portion of the hemor-
rhage in the caudal lobe is noted just dorsal to the hilar region
on the lateral view.
Lung injury 65
2

Case 2.25
Signalment/History: “Tammy” was a 6-year-old, female
Labrador Retriever who had been struck by an automobile
one hour earlier.
Physical examination: She was slightly dyspneic and non-
weight bearing on the right forelimb.
Radiographic procedure: Studies were made of the thorax
with additional views of the right scapula.
Radiographic diagnosis (thorax): Collapse of the right
middle lobe and an increase in density due to hemorrhage
within the caudal lung lobes were noted. The caudal lobes sil-
houetted with the diaphragm on the lateral view. Because of
the lung lobe collapse, the cardiac silhouette was shifted to-
ward the right. Pocketing of pleural fluid was seen around the
more severely affected lobe. Compensatory overinfiltration of
the caudal lobe resulted in a cranial shifting of the right mid-
dle lobe. The diaphragmatic shadow could be seen on the DV
view. No injury to the thoracic wall was noted.
2

Radiographic diagnosis (scapula): A comminuted frac-
ture of the right scapula was present, but did not extend into
the shoulder joint.
Treatment/Management: Air-bronchograms could be
clearly identified in “Tammy’s” lungs indicating a more ex-
tensive amount of fluid than seen in the typical contused lung.
She was given several days rest and returned to her owner. The
fracture was not treated.
Lung injury 67
2

Case 2.26
Signalment/History: “Sampson” was a 3-month-old, male
German Shepherd that had been struck by a large board falling
across his body.
Physical examination: The dog was in shock when pre-
sented and showed great pain. An abdominal tap was negative
for fluid.
Radiographic procedure: The thorax was radiographed.
Radiographic diagnosis (day 1):Pulmonary contusion was
principally in both caudal lobes and the right cranial lobe, with
the presence of air bronchograms. Minimal loculated pleural
fluid was present on the left side caudally. The diaphragm ap-
peared to be intact, although the right crus could not be seen
clearly.
2
Day 1

Radiographic diagnosis (day 3): Radiographs made two
days later showed a clearing of the pleural fluid on the right,
but increased consolidation of the right middle lobe and left
cranial lobe. The right cranial lobe was hyperinflated. Pleural
fluid was considered to be possibly present on the left.
Treatment/Management: Failure of the fluid in the lung to
clear within 48 hours indicates a more severe injury than just
pulmonary contusion. The patient was treated with antibiotics
and recovered suggesting that pneumonia had been present
secondary to the trauma.
Lung injury 69
2
Day 3

Case 2.27
Signalment/History: “Sugar Bear”, a 4-year-old, male Aki-
ta, had been caught in a fire one week earlier. He had been
unconscious immediately after the fire, but then appeared to
make a complete clinical recovery.
Physical examination: He was reported to convulse daily,
but appeared relatively normal when presented in the clinic.
because of the history.
Radiographic diagnosis: An increase in fluid density in the
central portion of the lung field was associated with promi-
nent airway markings. The increase in fluid density around the
walls of the bronchi was thought to be associated with the in-
halation of noxious agents and also possibly with additional
thoracic trauma associated with the fire. A region in the left
cranial lobe had increased fluid density, but this was thought
to be due to the oblique position of the patient at the time of
radiography.
Treatment/Management: “Sugar Bear” failed to improve
clinically and was euthanized. At necropsy, cortical necrosis
was noted secondary to the anoxia from smoke inhalation
at the time of the fire. In the lungs, the main bronchi and
smaller broncheoli were filled with a tenacious clear fluid with
“black specks”. The alveolar walls were congested. All the
lung pathology was secondary to the inhalation of smoke.
2

Case 2.28
Signalment/History: “Lady” was a 4-year-old, female,
mixed-breed dog who had been hit by a car.
Physical examination: On physical examination, she was
dyspneic with decreased lung sounds on the left side.
Radiographic procedure: Studies of the thorax were made.
Radiographic diagnosis: The heart shadow was separated
from the sternum on the lateral view and the lung lobes were
separated from the chest wall on the left indicative of a pneu-
mothorax. An increase in lung density suggested pulmonary
contusion/hemorrhage in both the right and left lung lobes. A
large lucent cyst with sharp margins was in the left caudal lobe
and represented a traumatic pneumatocele (arrows). A second
smaller cyst was located just lateral to the larger lesion. A
metallic object lay in the ventral mediastinum (air-gun pellet).
Minimal peritoneal effusion (hemorrhage) was noted, indicat-
ed by a inability to identify the ventral border of the liver.
Treatment/Management: Because of the suspected peri-
toneal fluid, “Lady” had a retrograde cystogram performed
that proved the urinary bladder to be intact. However, she was
found to have a pelvic fracture involving the left hip joint.
Continued monitoring of the effects of the injury to the lungs
was important in this dog because the finding of the pneuma-
tocele indicated a more severe trauma than is usually seen in
trauma patients with the possibility of secondary infection oc-
curring because of the pooling of stagnant blood.
Lung injury 71
2

Case 2.29
Signalment/History: “Snagglepus” was a 4-month-old, fe-
male Doberman Pinscher who had been hit by a car and was
brought immediately to the clinic.
Physical examination: Breathing was labored.
Radiographic procedure: Radiographs of the thorax were
made.
Radiographic diagnosis (day 1): Severe pulmonary hem-
orrhage affected all the lung lobes, but was more severe on the
right. Generalized pleural fluid was also more evident on the
right. Both the thoracic wall and the diaphragm were intact.
2
Day 1

Radiographic diagnosis (day 3): These radiographs
showed a marked clearing of the pulmonary edema and hem-
orrhage from all but the right cranial lobe. Pleural fluid was
still present. Note that the thoracic cavity remained as dis-
tended as at the time of presentation.
Treatment/Management: It was recommended that the
dog remain hospitalized to await the diagnosis of why the right
cranial lobe was failing to re-aerate. This was especially wor-
risome because the cranial lung lobes are normally well pro-
tected from trauma by the shoulder muscles. The possibility of
either secondary pneumonia or a bronchial blockage from a
mucous plug causing an obstructive atelectasis was considered.
The normal anatomical location of the airways in the lobe
tended to rule out torsion.
The puppy was discharged several days later in good health. As
in most patients, the cause for the delay in healing of the cra-
nial lobe could not be determined absolutely.
Lung injury 73
2
Day 3

Case 2.30
Signalment/History: A stray female cat was observed being
struck by a car and was brought to the clinic.
Physical examination: A limited examination indicated
dyspnea and abnormal lung sounds.
Radiographic procedure: Thoracic radiographs were
made.
Radiographic diagnosis (day 1): The left thoracic wall had
minimal subcutaneous emphysema. The adjacent left lung
lobes were increased in fluid density, suggesting pulmonary
contusion and hemorrhage. A minimal pneumothorax was
present and of a closed nature. On the lateral view, pleural flu-
id could be seen on the left trapped in the fissure between the
cranial and caudal lobes. A single non-displaced fracture was
noted in the left 8th
rib.
2
Day 1

Radiographic diagnosis (day 2): Radiographs made the
next day showed a marked increase in liquid density within
the right cranial lobe and both parts of the left cranial lobe,
with accentuation of the air-bronchogram pattern. The vol-
ume of the pleural fluid was increased and silhouetted with the
cardiac silhouette. Note in particular the fluid between the
cardiac silhouette and the sternum. The subcutaneous air had
also increased in volume.
Treatment/Management: The increase in severity of the
radiographic changes matched the increase in severity of the
cat’s clinical signs, especially the dyspnea. The lungs showed
an increasing fluid density that could be explained either by
continued hemorrhage or a secondary pneumonia. The stress
aerophagia continued to demonstrate something of the clini-
cal status of the cat.
The cat was treated medically and finally recovered. She was
later adopted. The amount of body fat suggested that for a
stray cat, she had been eating rather well.
Lung injury 75
2
Day 2

Case 2.31
2

Signalment/History: “Teddy Bear” was a 3-year-old, fe-
male Chow Chow who had been in chronic renal failure for
the previous 18 months. She had been undergoing dialysis and
was a frequent patient in the hospital. She had chewed out a
PEG tube placed earlier and even proceeded to pull out a sec-
ond tube. The latest admission was because of persistent pleu-
ral fluid and having suddenly developed dyspnea.
Radiographic procedure: The thoracic studies were made
because of the dyspnea.
Radiographic diagnosis: An area with a mottled, granular
appearance was noted lying within a fluid dense mass in the
right cranial hemithorax. This mass had an intermixed lucent
gas pattern that suggested necrotic tissue often present follow-
ing a lung torsion. A rim surrounding the mass had a homo-
geneous soft tissue/fluid density. The right cranial lobe
bronchus terminated just distal to the carina. The right middle
lung lobe was also airless with bronchial termination. Exten-
sive freely moving pleural fluid was noted on both the DV and
VD views. The chest wall was expanded and the diaphragm
was caudal and flattened. The trachea was on the midline sug-
gesting there was no mediastinal mass. Chronic secondary
joint disease was evident in both shoulders
Treatment/Management: A right cranial and middle lung
lobectomy was performed to correct the chronic lung torsion.
The history of repeated anesthesia in which the patient was
placed in a unusual body position plus the presence of pleural
fluid were probable causes of the torsion of the lung lobes.
Lung injury 77
2

Case 2.32
Signalment/History: “Pal” was a 1-year-old, male Cocker
Spaniel who was severely dyspneic after being struck by a car.
Physical examination: The dog had a swollen abdomen and
was comatose.
Radiographic diagnosis: The right lung lobes and the left
caudal lobe showed a marked increase in fluid density, proba-
bly a result of hemorrhage from lung contusion. Only the left
cranial lobe was fully aerated, while the others had an in-
creased fluid density that silhouetted with the cardiac silhou-
ette. The marked increase in fluid density in the lung lobes
indicated atelectasis plus pulmonary hemorrhage. The pul-
monary vessels were small suggesting hypovolemia.
The bilateral pneumothorax was easily identified because of
the air contrasting with the fluid content in the lungs. A min-
imal amount of pleural fluid was pocketed caudally, adjacent
to the diaphragm at the costophrenic angles. The cardiac sil-
houette was rounded with increased sternal contact suggesting
a hemopericardium. A mediastinal shift to the left was noted.
The dilated gas-filled stomach suggested panic breathing and
the severity of the respiratory distress.
Treatment/Management: “Pal” died shortly after radiogra-
phy due to a ruptured liver with peritoneal bleeding, pul-
monary hemorrhage, pericardial hemorrhage, and cerebral
hemorrhage.
Comments: It requires the combination of atelectasis plus
pulmonary contusion to obtain a lung density of this severity.
2

Case 2.33
Signalment/History: “Shadow” was a 1-year-old, female
Great Dane who had sustained head trauma.
Physical examination: On physical examination, the left
pupil was not responsive to light and depressed frontal bone
fractures were noted.
Radiographic procedure: Because of the unknown nature
of the trauma, thoracic radiographs were made.
Radiographic diagnosis: A perihilar pattern of increased
pulmonary density unusual in a young dog was present and
was thought, because of the clinical history, to represent neu-
rogenic pulmonary edema. Pulmonary congestion was present
in the right lung lobes; perhaps a post-traumatic lung ede-
ma/hemorrhage. Pneumatoceles were present in the right
middle lobe (DV enlargement, arrows).
The pulmonary vessels could not be identified due to shock.
The thorax was expanded with scalloping of the lung borders.
The diaphragm was caudal and flattened.
Treatment/Management: Fortunately, members of this
breed possess massive frontal bones that provide good protec-
tion for the brain from direct trauma. “Shadow” recovered
and was ultimately released to her owners.
Lung injury 79
2

Case 2.34
Signalment/History: “Wojo”, a 1-year-old, male DSH cat,
had been caught in a garage door and was trapped in that po-
sition for 30 minutes, enduring great pressure on his thorax.
Physical examination: Dyspnea was severe.
made.
Radiographic diagnosis (day 1): Pulmonary infiltrate was
noted throughout all the lung lobes, being most prominent
caudally. Minimal pleural fluid was present. No injury to the
thoracic wall was detected. No peritoneal fluid was noted.
2
Day 1

Radiographic diagnosis (day 5): Radiographs made four
days later showed resolution of both the pulmonary and pleu-
ral fluid.
Treatment/Management: The pulmonary contusion was
probably the result of a rupture of pulmonary alveoli due to
the supreme effort required at inspiration against the great ex-
ternal pressure on the thorax caused by the door. However, an
air-bronchogram pattern was not prominent. The rather rapid
healing suggested that there was no direct trauma to the lungs
from the door closing on the cat.
Lung injury 81
2
Day 5

Case 2.35
2

Signalment/History: “Kila” was an 18-month-old, female
Golden Retriever who had been hit by a car 24 hours earlier.
Physical examination: She could not walk when presented
for treatment. However, she had a superficial pain reflex, a
normal panniculus reflex, and normal patellar reflexes.
because she was a trauma case. Additional views were made
centering on the thoracic spine.
Radiographic diagnosis: An accumulation of alveolar fluid
in the right lobes caused alveolar patterns. No air-bron-
chograms could be identified clearly. No pleural fluid was not-
ed. The diaphragm was intact. The chest wall was normal. The
cranial mediastinum was thought to be widened, especially
considering the rather thin body wall.
A fracture-luxation of T5–6 was noted (arrow).
Treatment/Management: Because the presence of pain
perception is a favorable finding, “Kila’s” fracture was treated.
Treatment was in the form of a body cast with the dog posi-
tioned beneath a metal “grate” to prevent movement. Later
radiographs made after clinical recovery showed the affected
vertebra to have remained in position.
Lung injury 83
2

Case 2.36
Signalment/History: “Harvey”, an 8-month-old, male
Hound, had a history of having been found recumbent by the
side of the road. The owners admitted that he had not been
well recently and had been coughing. The case was registered
as a possible “hit by a car”.
made because of the clinical history of a young dog with a
cough.
Radiographic diagnosis (day 1):A disseminated diffuse in-
crease in pulmonary density involved both the interstitium
and peribronchiolar tissues. In addition, a poorly marginated,
5-cm-in-diameter mass was located distally in the right mid-
dle lobe. Interstitial nodularity was adjacent to the mass lesion.
A round, well-marginated, 2-cm mass lay dorsal to the tracheal
bifurcation and was possibly a mediastinal lymph node. A
slight separation of the pulmonary lobes suggested pleural flu-
id. The diaphragm was located caudally and flattened. The
apex of the cardiac silhouette was shifted to the left chest wall,
possibly as an effect of pleural adhesions. Focal pleural thick-
ening was evident on the left chest wall also suggesting chron-
ic pleural disease.
2
Day 1

Radiographic diagnosis (10 months following the sur-
gical removal of the right cranial and middle lobes due
to foreign body induced bronchopneumonia): The
marked tracheal deviation to the right, right-shift of the car-
diac silhouette, and herniation of the left cranial lung apex into
the right hemithorax were all postsurgical. The pleural thick-
ening and fluid collection in the cranial portion of the right
hemithorax were the effects of the chronic pleuritis plus pos-
sible postsurgical changes. Generalized peribronchial thicken-
ing suggested persistent chronic bronchial disease, while the
prominent air bronchograms ventrally suggested a more recent
pneumonia.
Treatment/Management: “Harvey” was quickly seen on
the first study to have chronic lung disease with a possible mass
lesion. Following unsuccessful medical treatment, he was
treated surgically with removal of the pneumonic lung lobes
that were secondary to a foreign body.
Comments: The frequency of inhalation of plant awns with
associated pulmonary infection is influenced by the geograph-
ical location and is dependent on the presence of wild grasses
and a dry climate. “Harvey” was typical of many of these pa-
tients in that he continued to suffer from pulmonary disease as
seen on the follow-up radiographs. The role of possible trauma
from being struck by a car was not important in this patient.
Lung injury 85
2
10 months later

2.2.5 Pulmonary hematoma
Case 2.37
2

Signalment/History: “Corky” was a 5-year-old, male
Golden Retriever who had been struck by a car 10 days pre-
viously and had been hospitalized since that time. He was re-
ferred to this clinic for the repair of his pelvic fractures.
Physical examination: On physical examination, he was
8–10 % dehydrated, febrile, and had harsh lung sounds espe-
cially on the left.
thorax for the first time since the trauma.
Radiographic diagnosis (day 10 post trauma): Massive
thoracic wall injury was seen with fractures of 5 ribs on the left
with a marked displacement of the fragments. Unequal filling
of the left lung fields was evident. Caudal lobe hyperinflation
with generalized increased peribronchial shadows was present.
A sharply defined soft tissue mass, 2 x 3 x 3 cm in size, situat-
ed possibly in the caudal aspect of the left cranial lung lobe was
probably a post-traumatic hematoma (arrows). This was in-
dicative of a severe lung injury with parenchymal damage,
which had permitted the pooling of blood within the pul-
monary parenchyma.
An infiltrative pattern in the right caudal lobe included an air-
bronchogram. The presence of this type of infiltrative pattern
for a period this long after trauma suggested a secondary pneu-
monia following the original pulmonary hemorrhage. The left
hemidiaphragm was caudal and flattened. Minimal pleural flu-
id, probably the result of hemorrhage, was trapped around the
injured left lung. The dorsal crus of the diaphragm on the right
could not be identified due to silhouetting with the pneu-
monic lobe. The retrosternal lymph node was enlarged.
Treatment/Management: “Corky” had a cardiac arrest and
died 48 hours after the radiographic study.
At necropsy, a hematoma was identified on the cranial aspect
of the left caudal lung lobe. Lung sections from the right cau-
dal lobe had hemorrhage, fibrinous exudate, and parenchymal
necrosis typical of an acute coliform pneumonia. It was sus-
pected that E.coli had been present at the time of the injury as
a bacteremia and had subsequently localized in the injured
caudal lobes, which provided a good culture medium. The
distribution of the necrosis was different to the cranioventral
distribution typical of aerogenous pneumonias. The pleural
fluid had become infectious in nature. Myocardial injury was
present, but was limited to the outermost one-fifth of the
myocardium. The retrosternal lymph node was not examined.
Pulmonary hematoma 87
2

Case 2.38
Signalment/History: “Kami” was a 4-year-old, male Lhaso
Apso who had been bitten by a large dog.
cause of the size of the dog and because of the severe dyspnea.
Radiographic diagnosis: Both views of the thorax were at-
tempted, although it was thought that the positioning would
not be good.
Radiographic diagnosis: The large volume of generalized
subcutaneous air compromised the evaluation of the intra-
thoracic injury. The injury to the intercostal muscles was bi-
lateral and resulted in an increase in the distance between the
injured ribs. Most severe was the fracture of the 5th
rib on the
right, with fragment displacement. The pulmonary injury
affected the right middle lobe, which showed an increase in
fluid density due to hemorrhage. However, a more prominent
injury on the right was in the caudal lobe (arrows) and caused
a wedge-shaped pulmonary lesion indicative of an obstructive
atelectasis or possibly a large pulmonary hematoma. The dia-
phragm was intact. Free pleural air was pocketed on the right.
The sternal changes were congenital.
Treatment/Management: Despite the bilateral injury to
the thoracic wall and the obstructive atelectasis, “Kami”
recovered nicely with conservative treatment.
2

2.2.6 Interstitial nodules
Case 2.39
Signalment/History: “Little Girl”, a 9-month-old, female
DSH cat, had a history of dyspnea characterized by rapid
breathing. She had been listless for several months. Fecal ex-
amination was negative for lungworms.
Radiographic procedure (day 1): A patchy infiltrative pat-
tern was present throughout the lungs with a tendency toward
nodular formation. No pleural fluid could be seen. The di-
aphragm was intact but caudal in position. The cardiac silhou-
ette was normal in size, shape, and position. The differential
diagnosis included any granulomatous lesion. A metastatic tu-
mor was not considered because of the age of the patient.
Treatment/Management: The cat was treated with anti-
biotics without any improvement in her medical status.
왘왘
Interstitial nodules 89
2
Day 1

Radiographic diagnosis (day 25): Further coalescence of
the pulmonary nodules was seen with patches of emphysema-
tous lung. Minimal pleural fluid was present. A granulomatous
pneumonia remained the most likely diagnosis.
Treatment/Management: Because of the poor prognosis
associated with the lack of improvement in the status of the
kitten, the owners chose to have the patient euthanized.
Necropsy examination showed a marked involvement of all
lung lobes. Pus could be forced from the lung upon applica-
tion of pressure. The nodules were generally between 1 and 2
cm in diameter. The alveoli were distended and contained a
cellular population of macrophages and PMN cells. The
macrophages were filled with fat indicative of a chronic, lipid
inhalation pneumonia. The alveolar walls were thickened.
Presented with this information, the owner said that she had
been giving the cat oil daily to prevent “hair balls”. Without a
history of chronic administration of oil, a definitive diagnosis
could not have been reached from the radiographs and physi-
cal examination alone.
2
Day 25

2.2.7 Diaphragmatic hernia
Case 2.40
Signalment/History: “Sir” was a 6-month-old, male
Miniature Poodle, who had been struck by a car 12 hours ear-
lier.
Physical examination: No heart or lung sounds could be
detected on the right side.
Radiographic diagnosis: The right hemithorax was filled
with air-filled loops of small bowel. The heart was displaced
to the left and elevated. The diaphragm could not be seen on
either view. The increase in fluid density within the thoracic
cavity was due to a contusion of the lungs, pleural fluid, and
the fluid density of the bowel. The air- and ingesta-filled
stomach was identified in a near-normal location in the ab-
domen. The 4th
rib on the right was fractured near the cos-
tovertebral joint.
Treatment/Management: The diagnosis was rather easy
because the air-filled loops of bowel lay within the thoracic
cavity. The owners decided to have the hernia repaired at an-
other clinic and took the poodle home.
Diaphragmatic hernia 91
2

Case 2.41
Signalment/History: “Tuffy” was a 1-year-old, male,
mixed-breed dog, whose the owner thought he had been
kicked by a horse.
Physical examination: While the dog’s temperature was
normal, breathing was restricted and he was comfortable only
when standing. Heart sounds could not be detected on the left
side.
Radiographic procedure: Studies were made of the thorax.
Radiographic diagnosis:The diaphragm could not be iden-
tified on the left side on the DV view and was positioned cra-
nially on the left side on the lateral view. Both of these posi-
tionings were suggestive of diaphragmatic hernia. Ingesta or
fecal material within the thoracic cavity on the left supported
this diagnosis. A portion of the right hemidiaphragm was iden-
tified in its normal position, suggesting injury to the left side
only. The cardiac silhouette and the hilus were shifted to the
right with malposition of the main-stem bronchus to the left
caudal lobe; both suggestive of a mass lesion. Prominent air-
bronchogram patterns were noted indicative of alveolar flood-
ing. Minimal pleural fluid was more prominent on the left side
of the thorax. The liver shadow was difficult to localize.
Treatment/Management: The diaphragmatic hernia was
characterized by several radiographic features. Mediastinal shift
could be detected by locating the region of the tracheal bifur-
cation and the main-stem bronchi. Elevation of the tracheal
shadow resulted from lateral shifting of the heart. Uneven dis-
tribution of pleural fluid is common with a diaphragmatic her-
nia and often reflects the degree of lung lobe collapse.
Comments: In the young patient,
the pattern of calcification of the
costal cartilages is rather orderly.
2

Case 2.42
Signalment/History: A 3-year-old, male DSH cat was pre-
sented with a history of trauma that had occurred 10 days ear-
lier.
Physical examination: The cat was depressed and slightly
dyspneic on presentation.
Radiographic procedure: The whole body was included in
the study.
Radiographic diagnosis: Small bowel loops occupied most
of the right hemithorax with a mediastinal shift to the left. The
air-filled stomach remained within the abdomen, but was
shifted to the midline with the pylorus displaced ventrally and
cranially. No evidence of chest wall injury was noted. A cau-
dal displacement of the dorsal portion of the diaphragm could
be seen.
Treatment/Management: The diaphragmatic tear extend-
ed from the sternal attachment 5 cm to the right. All of the
small bowel, liver, and spleen were within the right hemi-
thorax. The liver had a 360° twist around its pedicle and was
incarcerated. The cat survived the surgery and was released to
his owner.
2

Case 2.43
Signalment/History: “Kitten” was a 10-month-old, female
mixed breed cat with a history of dyspnea lasting for several
months. The owners suspected that the cat had been trauma-
tized six months previously.
Physical examination: Lung sounds were abnormal and the
abdomen palpated empty.
made.
Radiographic diagnosis (thorax): A number of intra-
thoracic masses were present, some with uniform fluid densi-
ty and others that included air. The cardiac silhouette was
shifted dorsally along with the trachea. The diaphragm could
not be identified ventrally or on the right side. The lungs were
atelectic.
2

Radiographic diagnosis (abdomen): A large fluid density
mass with a scattered mineralized pattern occupied the ventral
midabdomen. The ingesta-filled stomach was crowded cra-
nially and ventrally. Air-filled bowel extended cranially on the
right into the thoracic cavity.
Comments: The dyspnea caused by the diaphragmatic her-
nia had been made more severe by the progressive increase in
the size of the cat’s gravid uterus.
2

Case 2.44
2

Signalment/History: “Menace” was a 6-year-old, male
DSH cat with a two-month history of dyspnea, anorexia, and
depression. The differential diagnosis included thymic lym-
phosarcoma.
Physical examination: The examination did not contribute
anything to the evaluation of the case.
Radiographic procedure: The thorax was studied because
of the tentative diagnosis of lymphosarcoma. An additional
single lateral view of the abdomen was made.
Radiographic diagnosis: The thorax was expanded to max-
imum size. The pleural space was filled with air-containing
viscera. The trachea was shifted to the left. The cardiac sil-
houette was in the left hemithorax. The diaphragm was locat-
ed caudally, but could not be visualized on the ventral mid-
line.
The single lateral view of the abdomen showed an absence of
small bowel shadows.
confirmed by surgical exploration of the abdomen. Primary
pulmonary disease was not considered on these radiographs
because the atelectasis was thought to be caused by the pleural
masses. Both pneumothorax and pneumomediastinum were
present the day following surgery. Radiographs made three
days post-surgery showed a minimal persistent pneumothorax;
however, the lungs were expanded and of normal density.
Comments: Failure to identify the abdominal organs in their
normal location often suggests their displacement into the
thoracic cavity and diagnosis of a diaphragmatic hernia.
2

Case 2.45
Signalment/History: “Trouble” was a stray 1-year-old,
male DSH cat who was presented with a history of rapid
breathing for the previous five days.
Physical examination: Little could be learned from the ex-
amination. The thoracic wall was intact; however, injury was
suspected on palpation of the costal cartilages. The heart and
lung sounds could not be auscultated on the right. Cardiac
sounds were stronger on the left.
made.
Radiographic diagnosis: An intrathoracic mass on the right
side caused a mediastinal shift to the left and an elevation of the
trachea. The heart was in contact with the left thoracic wall.
The lung lobes appeared to be displaced dorsally. In the right
hemithorax, the lung margins were retracted from the chest
wall. A partial diaphragmatic shadow could be identified dor-
sally on the lateral view. The presence of a pleural mass was
thought to be the cause of the retraction of the lung lobes and
the mediastinal shift. Pleural fluid was thought probable. No
thoracic wall injury was noted except for fractures of the cau-
dal costal arches. The gastric shadow was shifted cranially to lie
adjacent to the diaphragm, but remained within the abdomi-
nal cavity. The tentative diagnosis was a diaphragmatic hernia.
Treatment/Management: “Trouble” was successfully op-
erated for the hernia.
Comments: While a thoracic mass other than a pleural mass
resulting from a diaphragmatic hernia was possible in this pa-
tient, it was unlikely considering the
age, clinical history, and the pres-
ence of the costal arch fractures.
2

Case 2.46
Signalment/History: “Siri” was a 3-year-old, female
Siamese with a history of presumed trauma according to her
owner. She was known to have bilateral hip dysplasia.
Radiographic procedure: “Whole-body” radiographs were
made because of the unknown nature of the injury and the
small size of the patient.
Radiographic diagnosis: Cranial displacement of the right
hemidiaphragm was matched by a caudal displacement of the
left hemidiaphragm. More important in the diagnosis of a dia-
phragmatic hernia was the cranial displacement of the air-
filled pyloric antrum. The heart was shifted into the left
hemithorax. Minimal pleural fluid was trapped around the
heart and the ventral mediastinum. A minimal increase in right
middle lobe density suggested pulmonary hemorrhage second-
ary to trauma. No sign of chest wall trauma was noted.
Treatment/Management: The diagnosis of a diaphragmat-
ic hernia was suggested by the shift in position of the air-filled
abdominal organs, the asymmetry of the crura of the dia-
phragm, and the inability to see the cupula of the diaphragm.
The patient was thin with little contrast between her abdom-
inal organs because of the lack of fat, which suggested that the
injury may have been long-standing. The radiographic diag-
nosis of a hernia is much more difficult in a patient in which
a hollow viscus is not displaced. The hernia was proven surgi-
cally.
Whole body radiographs should include the thoracic inlet and
the pelvic canal. These were cropped for publication.
2

Case 2.47
Signalment/History: “Dale” was a 1-year-old, male
Siamese with a chronic cough of two months duration.
to evaluate the cause of the coughing. The history did not sug-
gest a traumatic etiology.
Radiographic diagnosis: Radiodense material having the
appearance of small bone fragments was located within the
central portion of the thoracic cavity caudally. The mass was
lobulated and surrounded by pleural fluid that caused silhou-
etting with the diaphragm ventrally. The mass effect elevated
the trachea dorsally. The heart was difficult to visualize, but a
shadow typical for the heart was displaced dorsally. The bony
fragments were treated as a contrast agent enabling the loca-
tion of the displaced gastric shadow.
repaired successfully. The cause for the hernia or the time of
the injury was not determined.
2

Case 2.48
Signalment/History: “Jazabelle”, a 3-year-old, female DSH
cat, was depressed without any clinical history of trauma.
Physical examination: The clinical examination was unre-
markable except for the failure to auscultate lung sounds on
the caudal right side.
Radiographic procedure: Radiographic views of the tho-
rax were made.
Radiographic diagnosis: A mass effect was created in the
caudal right thorax silhouetting with the diaphragm and dis-
placing the heart markedly to the left. Air-filled bowel loops
were present within the mass. If pleural fluid was present, it
seemed to be trapped on the right side caudally. Stomach air
could not be identified in its normal position within the ab-
domen. A congenital anomaly affecting the xiphoid was pres-
ent; a type rather common in the feline.
Comments: Many pulmonary lesions can become consoli-
dated and cause trapped pleural effusion, however, major
bronchi should be at least partially identifiable throughout the
mass. In this cat, the trachea was shifted to the left and no air-
way shadows could be seen within the mass. The large air
shadow extending from the cranial abdomen to the right
hemithorax was indicative of small bowel and confirmed the
diagnosis of a diaphragmatic hernia.
2

Case 2.49
Signalment/History: This cat had no history of trauma, but
had been listless for the previous few days with more recently
occurring episodes of dyspnea.
Physical examination: Heart and lung sounds could not be
heard on the right side.
thorax with the possibility of a contrast study if required.
Radiographic diagnosis: A mass-like lesion lay in the cau-
dal right hemithorax and extended into the caudal left
hemithorax with displacement of the heart shadow cranially,
dorsally, and to the left.
Because of the failure to identify any air-filled bowel loops in
the thoracic cavity, a barium meal was used which clearly
showed the displacement of the stomach into the thoracic
cavity.
Treatment/Management: The diagnosis was confirmed at
surgery.
2
Noncontrast

2
Contrast

Case 2.50
2

Signalment/History: “Cody” was an 11-month-old, male
Labrador Retriever who had been hit by a car four hours ear-
lier.
Physical examination: The dog was dyspneic and appeared
to have great pain on palpation of the lumbar spine.
Radiographic procedure: Only lateral radiographs were
made because of the suspicion of extensive injuries.
Radiographic diagnosis: The pleural fluid was thought to
be hemorrhage. In addition, an increase in fluid density in the
lungs was noted. An elevation of the cardiac silhouette sug-
gested either displaced abdominal organs or some other pleu-
ral mass. The diaphragm could not be completely identified
and provided another feature suggestive of a diaphragmatic
hernia. The liver shadow was displaced cranially into the tho-
racic cavity and the stomach axis was shifted cranially. Neither
the spleen nor the urinary bladder could be identified within
the abdominal cavity.
A fracture-luxation at L4–5 did not cause marked segmental
displacement, but did indicate additional trauma. Following
identification of the spinal fracture, lateral views of the thora-
columbar spine were made permitting further identification of
the fracture with small fragments identified within the spinal
canal. Retroperitoneal fluid was suggestive of hemorrhage as-
sociated with the fractures.
repaired and the vertebral fracture/luxation was stabilized sur-
gically.
The status of the urinary system remained in doubt. The uri-
nary bladder appeared intact on a retrograde cystogram using
60 ml of contrast agent. On an excretory urogram using 70 ml
of contrast agent injected intravenously, positive contrast
agent was extravasated retroperitoneally and peritoneally
around the left kidney, suggesting a ureteral avulsion on that
side. The renal pelvis on the right was distended indicating
obstruction to flow and a possible right ureteral tear as well.
The urinary lesions were both treated conservatively because
of the owner’s choice not to spend additional money. “Cody”
survived and was subsequently released to his owner.
2

Case 2.51
Signalment/History:“Morris” was a 1-year-old, male DSH
cat that had possibly been traumatized 48 hours earlier. Ac-
cording to the owner, he had been either struck by a car or
kicked by a cow.
Physical examination: The cat was dyspneic and could not
bear weight on the left pelvic limb.
and pelvis.
Radiographic diagnosis (thorax): The pericardial sac was
dilated and contained gas-filled small bowel loops that ex-
tended from the abdomen through the diaphragm into the
pericardial sac. The trachea was displaced dorsally by the mass
effect. The surrounding lung appeared normal in appearance.
Note the appearance of the body of the 7th
thoracic vertebral
segment. Hemivertebrae are unusual in cats. Could this be a
compression fracture?
2

Radiographic diagnosis (pelvis): The fracture of the left
femoral neck was intertrochanteric and extracapsular. The age
of the fracture was difficult to determine because of the frag-
ment position.
Treatment/Management: Pericardio-diaphragmatic her-
nias often display a change in dynamics following trauma. At
surgery, the liver, gall bladder, most of the jejunum, the ileum,
and a part of the colon were within the pericardial sac. The ra-
diographic appearance of the lung tissue was normal regardless
of its being compressed by the enlarged pericardial sac.
2

2.2.8 Pleural air
Case 2.52
Signalment/History: “Ruff” was a 6-month-old, male
Golden Retriever who had been struck by a car 3 days previ-
ously.
Physical examination: Palpation of the thorax revealed a
probable injury to the caudal ribs on the right. The dog
breathed in a careful manner and was unwilling to take a deep
breath.
thorax using a technique that would permit evaluation of the
ribs.
Radiographic diagnosis (day 1, thorax): Radiographs
showed a pneumothorax that was characterized by elevation of
the cardiac silhouette away from the sternum and separation of
the borders of the caudal lung lobes from the diaphragm. Pul-
monary contusion was noted adjacent to the fractures of the
9th
, 10th
, 11th
, 12th
, and 13th
ribs on the right. The fluid densi-
ty in the cranial mediastinum adjacent to the sternum was
probably a hemomediastinum. A prominent skin fold extend-
ed across the caudal right lung field on the DV study.
2
Day 1

Radiographic diagnosis (day 1, abdomen; lateral view
only): Abdominal radiographs showed a physeal fracture of L4
with separation and displacement of the cranial end plate.
Small bowel loops were distended with fluid. Skin folds were
prominent in the cranial abdomen.
왘왘
Pleural air 109
2

made 11 days later showed clearing of the fluid from the lungs
and disappearance of the pleural air.
Treatment/Management: The bowel was possibly distend-
ed because of the trauma itself or perhaps due to an injury to
the spinal cord. No clinical signs were associated with the
small bowel and no treatment was required.
The patient was re-evaluated 11 days after the initial presenta-
tion for neurological deficits and was noted to only have pain
over the lumbar spine and some hesitancy in walking. He was
treated with cage rest for several weeks and was able to walk
normally when released.
Comments: Rib fractures are most easily recognized radio-
graphically when the fractures are within the bony portion of
the rib and there is a marked displacement of the fragments.
Fractures near the costovertebral joints are surrounded by
heavy muscle and do not usually show fragment displacement.
Fractures near the costochondral junction are difficult to iden-
tify because of the cartilage content of the ribs. Fortunately,
these types of fracture are not of great clinical importance and
when over-looked, probably do not affect the selection of
treatment or prognosis of the case.
2
Day 12

Treatment/Management:“Pumpkin” died shortly after the
radiographs were made. The necropsy findings were limited
to the contused lung with some pleural hemorrhage in addi-
tion to fractures of the costal arches. The air-filled bowel was
apparently the result of aerophagia.
Case 2.53
Signalment/History: “Pumpkin”, a 5-month-old, female
DSH cat, had been struck by an automobile.
Physical examination: The cat was presented in severe re-
spiratory distress.
Radiographic procedure: The whole body was radio-
graphed.
Radiographic diagnosis: Extensive pulmonary hemorrhage
was noted throughout the lungs. It was unusual that the pneu-
mothorax could be seen on the lateral view, but was difficult
to identify on the DV view as it only caused a thin radiolucent
line along the left thoracic wall. The diaphragm was intact on
both views.
Stress aerophagia had resulted in an air-filled stomach and
bowel loops. Distended bowel loops of this degree could be
the result of an ileus secondary to loss of blood supply to a por-
tion of the gut or torsion of the mesenteric blood supply.
Identification of the ventral border of the liver ruled out the
accumulation of peritoneal fluid. Note the absence of the usu-
ally large fat-filled falciform ligament.
Comments: Although the degree of pulmonary contusion
was not severe, what was important in this patient and led to
her death was the fact that all of the lobes were similarly af-
fected.
Pleural air 111
2

Case 2.54
Signalment/History: “Greizelda” was a 2–year-old, female
Great Dane presented with a history of having had dyspnea for
one week.
thorax.
Radiographic diagnosis (first study): A pneumothorax
caused marked lung lobe atelectasis and separation of the car-
diac silhouette away from the sternum. A single air-filled cyst
in the lung was identified just caudoventral to the carina.
Treatment/Management: The thorax was tapped and
4,800 ml of air was removed from the pleural space.
2
First study

Radiographic diagnosis (second study): The second ra-
diographic study showed a marked reduction of the volume of
the pneumothorax. The right middle lobe remained collapsed
(arrow).
Treatment/Management: It was not known on which side
the pneumothorax originated. Because of the persistent col-
lapse of the right middle lobe, the surgeon chose to perform a
thoracotomy on that side and luckily was able to identify mul-
tiple pulmonary cysts in all of lobes.
Histologic examination of the lobes suggested some superficial
cysts were lined with ciliated columnar and stratified squa-
mous epithelium, while others more deep in location indicat-
ed an etiology of chronic bronchiectasis.
Pleural air 113
2
Second study

Case 2.55
2

Signalment/History: “Sadie” was a 3-month-old, female
Golden Retriever puppy with a history of a successful removal
of a bronchial foreign body the day before. Removal of gastric
foreign bodies was attempted at the same time and was only
partially successful. The owner was concerned about the con-
dition of the patient feeling that she was not breathing nor-
mally.
made.
Radiographic diagnosis: Pneumothorax was present with a
suspected collapse of the accessory lung lobe. A small amount
of pleural effusion was noted. The thoracic wall was normal
except for malunion fractures of the 9th
and 10th
ribs on the
right. The gastric metallic foreign body was thought to be a
tack.
Differential diagnosis: The atelectasis of the accessory lobe
suggested injury to that bronchus. The pneumothorax was bi-
lateral and had occurred after bronchoscopy and endoscopy.
No evidence of pneumomediastinum could be seen. The ori-
gin of the intrathoracic air is presumably secondary to a punc-
ture of the trachea, bronchus, or esophagus with formation of
a tract through the mediastinum.
How long the bronchial foreign bodies had been present could
not be determined. It was possible that the foreign bodies had
resulted in a secondary, inflammatory lesion in the tracheal or
bronchial wall or even an esophageal wall lesion. It was also
possible that a tear in the wall of the bronchus or trachea had
occurred during removal of the foreign body, or that a tear in
the esophageal wall had occurred during removal of the gas-
tric foreign body (a piece of glass).
Comments: Note the large costochondral “knobs” typical for
this stage of skeletal development.
Malunion fractures of the ribs are not uncommon in puppies,
but the cause is rather difficult to explain.
Note the absence of peritoneal fat in this puppy. The small
bowel gas pattern is typical for an active animal frequently
swallowing air.
Pleural air 115
2

Case 2.56
Signalment/History: “Trixie” was a 7-year-old, female
DLH cat who had been bitten by a dog an hour earlier.
Physical examination: The cat was dyspneic. Subcutaneous
air could be palpated on the right chest wall.
made.
Radiographic diagnosis (day 1): A pneumothorax was in-
dicated by separation of the cardiac silhouette from the ster-
num. Subcutaneous emphysema was evident on the right. An
increase in lung density dorsally on the right was noted; how-
ever, the oblique positioning made evaluation difficult. In ad-
dition, this obliquity falsely suggested rib fractures. The di-
aphragm was intact.
2
Day 1

Radiographic diagnosis (day 3): The radiographs made 2
days later clearly showed the resolution of the pneumothorax
and most of the pulmonary hemorrhage. This study showed
more clearly the absence of rib fractures.
Comments: The distribution of lung hemorrhage was some-
what unique in “Trixie” in that the dorsal lobes are generally
better protected from trauma. However, the nature of a bite
wound in a small patient permits any part of the thorax to be
injured by the puncture wounds. Fractures were thought to be
present near the costovertebral joints, an area difficult to diag-
nose. The location of the lung contusion gives support to the
possibility of rib fractures in this region.
Pleural air 117
2
Day 3

Case 2.57
Signalment/History: “Murphy” was a 9-year-old, male
Border Collie who underwent anesthesia for a myelogram.
The radiographic procedure was delayed and he remained
anesthetized for a prolonged period of time.
Radiographic procedure:Thoracic studies were made prior
to the myelogram, following the use of positive pressure, and
during the use of positive pressure.
Radiographic diagnosis (prior to myelography under
anesthesia): Marked atelectasis of the right lung was com-
pensated by the hyperinflation of the left lung. The resulting
mediastinal shift was prominent.
Radiographic diagnosis (natural respiration under
anesthesia following positive pressure): Some reinflation
of the right lung had occurred, but all the lobes remained par-
tially atelectic.
2
Prior to myelography Natural respiration

Radiographic diagnosis (made during use of positive
pressure under anesthesia): The right lung was reinflated.
Minimal pleural fluid was evident. The left cranial and acces-
sory lobes fail to re-inflate completely.
Comments: Atelectasis associated with anesthesia and pro-
longed patient positioning without manual inflation of the
lungs is common. Because of the time involved in some radio-
graphic procedures, it is frequent that during the series of ra-
diographs directed at another part of the body, atelectasis is
noted. This case is more severe than usual, possibly due to a
bronchial mucous plug that functioned as a one-way valve.
Pleural air 119
2
Positive pressure

Case 2.58
Signalment/History: “Shorty” was a 2-year-old, male Chi-
huahua mixed breed who was presented at the clinic follow-
ing being attacked by a larger dog.
Physical examination: The patient was dyspneic and in-
juries to the thoracic wall were present.
Radiographic diagnosis (day 1): Subcutaneous emphyse-
ma was evident on the right side with increased separation be-
tween the 6th and 7th ribs. There was also a single fracture of
the right 6th
rib. Marked pneumothorax on the right caused
separation of the atelectic right middle and caudal lung lobes
from the diaphragm and from the chest wall. The pneumo-
thorax resulted in a minimal elevation of the heart shadow
away from the sternum with displacement to the left. The dia-
phragm was intact.
2
Day 1

Radiographic diagnosis (day 3): Radiographs made on
day 3 showed a lessening of the volume of the pneumothorax.
The right middle and caudal lobes had regained a part of their
normal degree of aeration. The amount of subcutaneous air
had decreased.
왘왘
Pleural air 121
2
Day 3

Radiographic diagnosis (day 4): Radiographs made on
day 4 showed almost a complete disappearance of the pneu-
mothorax. The right middle and caudal lobes were more aer-
ated as indicted by the decrease in fluid density. The amount
of subcutaneous air continued to decrease.
Treatment/Management: “Shorty” was treated conserva-
tively and experienced a spontaneous clearing of his chest le-
sions.
Comments: Note the fluid density within the affected lung
lobes on the first study is more than would be expected with
only pulmonary contusion and was the result of atelectasis as
well. The return to near normal was to be expected in this
type of trauma patient.
2
Day 4

2.2.9 Tension pneumothorax
Case 2.59
Signalment/History: “Sam” was a 4-year-old, female
mixed breed dog who had been hit by a truck.
Physical examination: The dog was in shock and dyspneic
and the examination was limited.
thorax.
Radiographic diagnosis: The thoracic cavity was distended
with a tension pneumothorax and collapse of the lung lobes on
the left. Pulmonary contusion of the lobes on the right could
also be seen. An air-bronchogram pattern was present in the
right lobes. The mediastinal shift was to the right.
Treatment/Management: “Sam” responded to immediate
treatment to relieve the pneumothorax. She was kept under
observation in an intensive care unit and the pneumothorax
did not recur. She was discharged within several days.
Tension pneumothorax 123
2

Case 2.60
Signalment/History: “Felix” was a 1-year-old, male DSH
cat with a 4-month history of left sided pyothorax with fre-
quent drainage. Streptococcus fecalis and E.coli had been cultured
from the lesion. Treatment was thought to be effective and he
was discharged from the clinic. The owner reported that clin-
ical signs had not improved and that the cat remained lethar-
gic and had problems in breathing.
Radiographic procedure: Progressive thoracic radiographs
were made.
Radiographic diagnosis (day 1): Noncontrast radiographs
showed a massive loculated pneumothorax in the caudal
hemithorax on the left, with a marked mediastinal shift to the
right. The heart shadow was against the right chest wall. The
right lung was partially atelectic. The left lung could not be
identified and was assumed to be collapsed.
2
Day 1, Noncontrast

Radiographic diagnosis (day 1): A barium swallow
showed normal passage of the contrast meal through an eso-
phagus that was markedly displaced to the right. A minimal
amount of contrast agent had been inhaled and was demon-
strated in the bronchi.
왘왘
2
Day 1, Barium swallow

Radiographic diagnosis (day 8): This study followed nee-
dle aspiration of the air, but showed no change in the volume
of the loculated pneumothorax that was being treated as a ten-
sion pneumothorax.
2
Day 8

Radiographic diagnosis (day 15): Following a thoracoto-
my in which a tear in the left lung was sutured, re-inflation of
the lung had occurred, although not completely. The pneu-
mothorax could not be identified on these radiographs. Pleu-
ral scarring plus the chest wall incision site had left a persistent
fluid-density shadow on the left side. The surgical incision on
the left was just caudal to the heart shadow as could be identi-
fied on the lateral view.
Treatment/Management: Failure of a pneumothorax to
heal quickly suggested a more severe pulmonary lesion or the
creation of a flap-like lesion that permitted the tension pneu-
mothorax to develop. The surgery was successful, although it
might be thought to have been delayed a bit too long.
2
Day 15

Case 2.61
2

Signalment/History: “Sly” was a 4-year-old, male Siamese
cat with no history of medical problems until 24 hours previ-
ously when he stopped breathing for some minutes. The own-
ers suspected trauma since the cat had been away from the
house for a few hours. The acute onset of dyspnea was re-
markable.
Physical examination: The severity of the dyspnea was se-
vere and as a consequence, a complete physical examination
was not possible. In addition, the cat was aggressive and fright-
ened. Despite this, the examination suggested that an upper
airway problem was not likely.
thorax.
Radiographic diagnosis: The thoracic cavity was distended
with a prominent mediastinal shift to the left. A unilateral ten-
sion pneumothorax on the right had caused the cardiac sil-
houette to move away from the sternum. The left lung was
partially atelectic. Most important was the failure to visualize
the air-filled lumen in the distal trachea that suggested a pos-
sible intratracheal foreign body (arrows).
Treatment/Management: Unfortunately, a decision was
made to treat only the pneumothorax. Following placement
of a chest drain, the dyspnea continued and the owners elect-
ed euthanasia rather than surgical exploration to determine the
cause of the pneumothorax.
On necropsy examination, a distal tracheal foreign body
(chicken bone) at the level of the origin of the bronchus to the
left cranial lobe had caused a severe necrotizing
tracheitis/bronchitis. The mediastinum was edematous, em-
physematous, and congested. Because of chronicity, adhesions
prevented a pneumomediastinum and instead a flap-like
opening in the wall of the mediastinum led directly to the pro-
duction of a tension pneumothorax. It was, therefore, under-
standable that despite the placement of a chest drain, the pneu-
mothorax had persisted. The mediastinitis was not appreciat-
ed clinically or radiographically; however, the abnormality in
the distal trachea should have received more immediate atten-
tion. Probably the increased lung density noted on the lateral
view was from the mediastinal effusion superimposed over the
density from the lungs.
2

2.2.10 Pneumomediastinum
Case 2.62
Signalment/History: “Clyde”, a 4-year-old, male Beagle,
was found by the owner to be “enlarged” and “distended”.
made.
Radiographic diagnosis: A prominent subcutaneous em-
physema and pneumomediastinum were evident. The in-
creased lung pattern was thought to be due to the subcuta-
neous air surrounding the thorax. No signs of injury to the
thoracic wall were noted. The multiple metallic subcutaneous
foreign bodies were shotgun pellets and although widely dis-
tributed, were probably not associated with the current clini-
cal problem.
Treatment/Management: The origin of the subcutaneous
air could not be ascertained radiographically. A careful search
of the skin located a small injury in the cervical region. At sur-
gery, a small hole in the trachea was found at the level of C3.
The overlying muscles were torn, suggesting a bite wound.
Any tear or rupture of the trachea or main-stem bronchi can
leak air.
An opening in the skin, especially in the axilla, can permit a
“pump-like” action that fills the subcutaneous space with air.
“Clyde” inflated the subcutaneous space on each inspiration
with air entering through the skin lesion and from the hole in
the trachea until he “pumped” himself up like a balloon. The
air had moved through the thoracic inlet and filled the medi-
astinal space.
2

Case 2.63
Signalment/History: A cat was found lying on the road by
a pedestrian and was brought to the clinic.
Physical examination: Subcutaneous emphysema was easi-
ly palpated over the thorax.
thorax and the whole body.
Radiographic diagnosis: Prominent subcutaneous emphy-
sema was evident, in addition to a pneumomediastinum and
retroperitoneal air. No signs of injury to the thoracic wall
could be seen.
Comments:Air will dissect from the subcutaneous space into
the mediastinal space. If the amount of air is sufficient, it is
possible that it will then dissect from the mediastinal space into
the retroperitoneal space. In this cat, the cause of the subcuta-
neous air was not known. The presence of the air suggests a
more severe lesion than is actually present. Determination of
the origin of the air is probably more critical in assigning its
clinical importance.
Pneumomediastinum 131
2

Case 2.64
Signalment/History: “Amee”
was a 2-year-old, female Borzoi pre-
sented in shock following being shot
in the neck and shoulder on the left.
Physical examination: The dog
was not able to stand and a complete
neurologic examination was not car-
ried out. Multiple soft tissue injuries
were noted around the head and
neck; however, it was not possible to
ascertain if there was any thoracic
injury.
Radiographic procedure: Lateral
radiographs were made of the head
and cervical region, with a complete
study of the thorax.
Radiographic diagnosis (head
and cervical region): Multiple
metallic pellets were located in the
head and cervical region indicating
an injury from a shotgun fired from
a short distance. No fluid density
was noted in the nasal passages or in
the frontal sinuses. Air that had dis-
sected between the soft tissues in the
neck permitted identification of
both surfaces of the tracheal walls
and was the origin of a pneumome-
diastinum.
2

Radiographic diagnosis (thorax): Subcutaneous emphyse-
ma in the cervical region was noted, plus a typical pattern of
air within the mediastinum that was indicative of a pneumo-
mediastinum. No evidence of lung injury was noted. Multiple
shotgun pellets were present.
Comments: Determining the source of the free air permits a
better understanding of the prognosis in such a case. The holes
in the skin can be large enough to permit the air to enter the
subcutaneous spaces and pass into the mediastinum, although
such holes are in themselves usually of little clinical impor-
tance.
It was possible in this case that one of the pellets had injured
the larynx or trachea permitting air to pass into the medi-
astinum. This would have been of greater clinical importance.
An injury to the esophagus may leak air and may lead to a me-
diastinitis and be of great importance clinically; however, it is
uncommon that an injury of this type would produce such a
prominent pneumomediastinum as seen in “Amee”.
Endoscopy is strongly indicated in this type of patient. Sever-
al of the pellets were malformed indicating that they had
struck bone.
Often only lateral views are made in a deep-chested patient
such as “Amee” until more is known of the injury.
2

Case 2.65
Signalment/History: “Wendy”, a large 1-year-old, female
Scottish Deerhound, had run into a tree the day before.
Physical examination: The dog would not walk on her
right forelimb. Crepitus was elicited following palpation of the
right shoulder. Movement of the shoulder joint was painful.
She was depressed with shallow breathing at the time of ex-
amination.
Radiographic procedure: Radiographic studies included
multiple views of the thorax plus the region of the right shoul-
der.
Radiographic diagnosis: Hyperlucent lung fields were not-
ed, but these were possibly due to the body conformation of a
deep-chested dog with a thin chest wall. All of the major cra-
nial mediastinal vessels and the tracheal wall could be clearly
identified indicating a pneumomediastinum. The pulmonary
vessels were also easily seen, but this was thought to be the re-
sult of the breed of dog and did not indicate an abnormal lung
pattern. The cause of the pneumomediastinum could not be
detected radiographically. A comminuted fracture of the right
scapula with fragment displacement was seen.
The study included a lateral view of the cervical region and
thoracic inlet, neither of which indicated injury to the upper
airway or esophagus
Treatment/Management: The scapular fracture was per-
mitted to heal without surgical stabilization of the fracture
fragments. The dog was discharged to the referring clinician
several days later.
Comments: Hyperlucent lung fields can be the result of the
conformation of the thorax or can represent an actual pul-
monary hyperinflation. The character of the pulmonary ves-
sels is more easily evaluated in patients in whom the lungs are
filled with air. Because of “Wendy’s” deep chest, caution
should be used in the evaluation of the cardiac silhouette on
the DV/VD views, since minimal obliquity of the thorax
markedly influences the appearance of the heart shadow.
2

Signalment/History: “Shep” was a 1-year-old, male Ger-
man Shepherd mixed breed, who had been hit by a car 12
hours previously.
Physical examination: The examination was difficult to
perform and only demonstrated marked dyspnea.
Radiographic procedure: Because of the dog’s difficulty in
breathing, only a lateral thoracic radiograph was made.
Radiographic diagnosis (day 1): The single lateral radio-
graph was underexposed, but still clearly showed a large pneu-
mothorax characterized by the elevation of the cardiac silhou-
ette away from the sternum and retraction of the lung lobes
dorsally from the spine and diaphragm. The ability to visual-
ize both sides of the tracheal wall, the aortic arch, and serosal
surface of the air-filled esophagus was indicative of a pneumo-
mediastinum. Collapse of the caudal lung lobes suggested both
pulmonary contusion and atelectasis. Liquid-dense, well-cir-
cumscribed pulmonary nodules plus air-filled, cyst-like lesions
were found in the dorsal lobes caudally. The diaphragm was
intact.
2
Case 2.66
Day 1

Radiographic diagnosis (day 4): The study on this day
showed a complete resorption of the pneumothorax, though
persistence of the pneumomediastinum. The lung lesions per-
sisted on the right side caudally. The fluid density nodule re-
mained in its dorsal position.
Treatment/Management: The nodular lesions suggested a
more serious lung injury that was slower to repair than just a
simple lung contusion following blunt trauma. The etiology of
the pneumomediastinum remained undetermined as frequent-
ly occurs.
2
Day 4

2.2.11 Hemomediastinum
Case 2.67
Signalment/History: “Romo” was a 5-year-old, male
Spaniel mixed breed, who had been hit by a car and was re-
ferred several days after the accident along with post-trauma
radiographs.
Radiographic diagnosis (immediate post-trauma): The
radiographs were made on expiration and were underex-
posed/underdeveloped. However, a large cranial mediastinal
fluid density could still be seen suggesting a mediastinal mass
probably the result of hemorrhage. The tracheal shadow was
shifted toward the right thoracic wall.
2
Day 1

Radiographic diagnosis (day 5, lateral view only): Re-
gression of the depth of the cranial mediastinal mass suggested
resorption of the blood. The lungs were normal for a dog this
age.
Comments: Hemorrhage within the mediastinum is thought
to not be as important clinically in the dog as in man, where
it pools caudally and does not drain freely resulting in a per-
sistent inflammatory process. In the dog, disappearance of the
blood appears to occur rather easily, but does occur at a slow-
er rate than the clearing of pleural fluid. It is helpful to moni-
tor the clearance radiographically since change would confirm
the suspicion of mediastinal fluid. A clinically more important
abscess, tumor, or hematoma in the mediastinum would not
change in size or shape as quickly on the follow-up radio-
graphs.
Hemomediastinum 139
2
Day 5

Case 2.68
2

Signalment/History: “Raggs” was a moderately obese, 7-
year-old, male Poodle with a history of having been hit by a
car seven days earlier.
Physical examination: He presented with a right forelimb
paralysis due to a probable avulsion of the brachial plexus.
to assess additional damage other than the neurological injury.
Radiographic diagnosis: An increase in cranial mediastinal
thickness with indistinct borders extended ventrally toward
the sternum and suggested mediastinal fluid possibly hemor-
rhage. Note that the thickness of the cranial mediastinal shad-
ow was greater than the width of the extrathoracic soft tissue,
indicating that the width was probably not the result of fat
deposition, but was a pathological condition. The generalized
increase in pulmonary density was probably due to under-
inflation of the lungs (note the cranial position of the dia-
phragm and moderate obesity of the dog). The obesity also
caused minimal pleural thickening. A single airgun pellet lay
dorsocaudaly within the mediastinum adjacent to the aorta
and esophagus. No bony abnormality was present.
Treatment/Management: The mediastinal thickness was
probably the result of hemorrhage. The airgun pellet may have
been unrelated to the current medical problem and seemed to
be in a position that would not cause any of the clinical signs.
The absence of bony changes is typical in patients with sus-
pected brachial plexus injuries.
“Raggs” was a patient with an old gunshot wound and a more
recent history of being hit by a car. Both traumatic events
needed to be given consideration in the exploration of the
clinical signs. Additional radiographic studies needed to be
made of the right forelimb and cervicothoracic spine because
of the paralysis.
“Raggs” did not show any marked improvement in his neu-
rological signs and was taken home by the owner without any
further radiographic studies being done.
Comments: The rule of measurement of the width of the
mediastinum on the DV view in comparison to the width of
the extrathoracic soft tissue is a helpful one in determining
whether the mediastinal width is the result of fat accumulation
or actually represents a pathological condition.
Hemomediastinum 141
2

2.2.12 Iatrogenic injury
Case 2.69
Signalment/History: “Princess” was a 2-year-old, female
mixed breed with a chronic, productive cough for the previ-
ous two months. The cough had been treated symptomatical-
ly with no success. No history of trauma was suggested.
Radiographic diagnosis (referral day 1): Radiographs
made at the referral clinic were indicative of a peribronchial
pulmonary pattern indicating a lower airway disease. The peri-
hilar region was more dense than normal, but did not appear
as a mass lesion. The possible value of a tracheal wash was dis-
cussed. An unexpected dyspnea had then developed within 12
hours after performing the tracheal wash and the patient was
referred.
2
Day 1

Radiographic diagnosis (day 3): A marked pneumothorax
was evident with retraction of the lung lobes from the thoracic
wall and separation of the cardiac silhouette from the sternum.
The pleural air was mostly on the left. The density of the at-
electic lungs was higher than before.
왘왘
Iatrogenic injury 143
2
Day 3

Radiographic diagnosis (day 4): The pneumothorax had
diminished and the lung lobes were more normal in appear-
ance with an increase in aeration.
Treatment/Management: It was feared that the tracheal
wash had been performed in such a manner that it caused a
tearing of the lung tissue resulting in the pneumothorax and
unexpected dyspnea. The dog recovered with conservative
treatment and was discharged.
2
Day 4

Case 2.70
Signalment/History: “Charlie Brown” was a 14-year-old,
male Miniature Poodle that had had a surgical procedure the
day before. He had made an unremarkable recovery, but was
found moribund 14 hours after the surgery.
Radiographic procedure: Radiographs were made because
of the abnormal lung sounds in the caudal portion of the tho-
rax.
Radiographic diagnosis: Increased fluid density was noted
in all the lung lobes except for the right cranial lobe. That lobe
was overinflated and had herniated across the midline to the
left side. Air bronchograms were present in all the affected
lobes in addition to an accentuated airway pattern. Silhouet-
ting caused an inability to visualize the caudal vena cava. No
pleural fluid could be identified. The diaphragm was intact.
Note the distention of the trachea.
Treatment/Management: The increase in pulmonary fluid
could best be explained by a high-permeability type pul-
monary edema due to an intrinsic trauma such as aspiration of
acid material. The patient died, but a necropsy examination
was not permitted.
2

Case 2.71
Signalment/History: “Saki” was a 3-year-old, male mixed
breed cat that had had dental surgery eight days earlier. The
day following surgery, he began to “inflate”.
Physical examination: A subcutaneous emphysema was
prominent.
entire body.
Radiographic diagnosis: The massive subcutaneous em-
physema and pneumomediastinum made evaluation of the
cervical trachea and lung fields difficult. The dorsal position of
the cardiac silhouette was the result of a congenital anomaly of
the xiphisternum.
Treatment/Management: Surgery was delayed for 12 days
because of a deteriorating clinical condition. At that time, a
3-cm long tear in the tracheal wall at the thoracic inlet was re-
paired. “Saki” died four days after surgery. The presence of a
necrotizing inflammatory process involving the larynx, tra-
chea, esophagus, and lungs was noted at necropsy. The exact
cause of the tracheal injury was assumed to have occurred at
the time of the anesthesia for dental surgery.
2

Case 2.72
Signalment/History: “Niko” was a 1-year-old, male Akita
with a history of dyspnea, tachypnea, and nasal hemorrhage. It
was thought that the epistaxis could be the result of pulmonary
hemorrhage because of its frothy appearance. The owner did
not know of any trauma.
Radiographic procedure (day 1): Multiple pulmonary
nodules had coalesced causing sufficient fluid density in the
lungs to create air-bronchogram patterns. The nodular pul-
monary pattern was thought to be nonspecific and possibly
compatible with a metastatic tumor, hematogeneous bacterial
pneumonia, fungal pneumonia, or parasitic pneumonia. No
pleural fluid was noted and the heart shadow was normal in
size, shape, and position.
Treatment/Management: A transtracheal wash was per-
formed that collected cells indicative of a pyogranulomatous
inflammation with a moderate eosinophilic component.
2
Day 1

Radiographic diagnosis (following the transtracheal
wash): A marked bilateral pneumothorax with atelectasis of
all lobes could be seen.
Comments: It was thought that the diagnostic procedure had
probably resulted in the pneumothorax.
2
Following transtracheal wash

Case 2.73
2

Signalment/History: “Fritz”, a 5-year-old, male Dober-
man Pinscher, had eaten a kitchen sponge. The owner had at-
tempted to induce vomiting by feeding him salt water and
vegetable oil. “Fritz” began to cough and gasp for air follow-
ing this medication.
Physical examination: The dog was febrile and dyspneic at
the time of admission to the clinic.
thorax. The study was overexposed but was not repeated.
Radiographic diagnosis: An increase in fluid density was
present within the right middle and accessory lobes with a
generalized air-bronchogram pattern supporting the clinical
diagnosis of an aspiration pneumonia. The presence of thick-
ened pleura adjacent to malunion fractures of the 6th
, 7th
, and
8th
ribs on the right suggested an old trauma.
A gastric foreign body was suggestive of the sponge that the
owners reported the dog had eaten.
Note the silhouetting of the radiodense accessory lung lobe
with the caudal vena cava making that structure difficult to vi-
sualize.
Treatment/Management: Lipid aspiration pneumonia was
diagnosed by combining the clinical history plus the radio-
graphic pattern. “Fritz” was radiographed eight days later and
the pneumonia was clearing. Lipid pneumonia clears more
slowly then typical airway-oriented pneumonia. It is difficult
to safely administer any oily medication since it does not stim-
ulate a cough reflex if it enters the upper airways and so it
tends to be inhaled.
2

Case 2.74
Signalment/History: “Ming” was an 8-month-old, female
Pekingese who had experienced difficulty swallowing a piece
of meat, and had choked and collapsed. The owner removed
the meat from the dog’s oropharynx and began cardiopul-
monary resuscitation.
Physical examination: When presented to the clinic,
“Ming” was alert, exhibited open-mouth breathing and had
marked bronchovesicular sounds bilaterally.
Radiographic diagnosis (day 1): A generalized increase in
pulmonary density was evident throughout the lung fields
with a minimal air-bronchogram pattern. The diaphragm was
located caudally and flattened, suggesting obstructive emphy-
sema. The cranial mediastinum was widened, but this was
thought to be breed dependent.
2
Day 1

Radiographic diagnosis (day 2): A persistent increase in
pulmonary density in the left lung strongly suggested pneu-
monia.
Treatment/Management: It was thought that because of
the small size of the dog, the resuscitation had caused trauma
to the thorax and that the changes within the lung lobes re-
presented pulmonary hemorrhage. It was also possible that
small portions of food had been aspirated and so the lung
changes could have been due to aspiration pneumonia. In
addition, an obstructive component may have been present
causing an associated obstructive atelectasis
The slow clearing of the pulmonary density plus the increase
in density in the left lung on the second day both suggested
the development of a secondary airway-oriented pneumonia.
A simple transudate secondary to trauma should have cleared
more quickly. The dog was discharged after a short stay in the
clinic.
2
Day 2

Case 2.75
Signalment/History: A 12-year-old, female Beagle belong-
ing to a colony was subjected to anesthesia for a dental proce-
dure. Following recovery, the dog was put into a cage for the
night. The next day, the dog was depressed and did not re-
spond to stimuli.
Radiographic diagnosis: Patchy pulmonary fluid was seen
in all the lobes, though it was more severe ventrally. Air-bron-
chogram patterns were noted peripherally. No pleural fluid
was noted. The trachea was dilated. The thoracic cavity was
expanded.
Treatment/Management: The dog died shortly after the
radiographs were made and was found at necropsy to have a
generalized, acute aspiration bronchopneumonia secondary to
aspirated vomitus.
2

Case 2.76
Signalment/History: “Zazzie” was a 15-year-old, female
Poodle that had been given anesthesia for a dental extraction
and had experienced a prolonged recovery. During this time,
manual inflation of the lungs was performed several times. At
presentation, she was awake but had difficulty in breathing.
Radiographic procedure: Radiographs were made to de-
termine the cause of the dyspnea.
Radiographic diagnosis: A bilateral pneumothorax was as-
sociated with atelectic lungs, which included radiolucent cysts
(pneumatoceles). No pleural fluid was noted. The chest cavi-
ty was expanded with the ribs at right angles to the spine. The
cardiac silhouette was separated from sternum due to the
pneumothorax.
Treatment/Management: The excessive pulmonary pres-
sure as a result of the “bagging” during anesthesia could have
resulted in rupture of pulmonary bullae causing the pneu-
mothorax. These bullae may have been developmental or sec-
ondary to chronic emphysema.
It is remarkable that “Zazzie”, after recovery, was admitted to
the clinic two months later with severe dyspnea and a tension
pneumothorax. She underwent cardiac arrest and died. On
necropsy, the lungs were atelectic, but in a randomly irregular
manner because of the interposed pulmonary cysts, which
were thought to be developmental.
2

Case 2.77
Signalment/History: “Codie”, a 2-year-old, female Ger-
man Shepherd, developed a sudden onset of dyspnea and a
suspicion of trauma.
Physical examination: Because of the dyspnea, the thorax
was radiographed immediately.
Radiographic diagnosis (day 1): Extensive pulmonary
fluid caused prominent air bronchograms in the middle lobes.
The etiology could not be elucidated from the radiograph;
however, a dilated esophagus depressed the air-filled trachea
and indicating the possibility of an aspiration pneumonia.
Note that the pulmonary lesions are only clearly identifiable
on the DV view. It is possible, but unusual for an airway-
oriented pneumonia to have a bilateral symmetry such as in
this case.
Treatment/Management: “Codie” was treated for pneu-
monia. She was operated on five days later for a suspected
intussusception detected on palpation as an abdominal mass
without any additional thoracic radiographs being made.
2
Day 1

Radiographic diagnosis (day 6): Radiographs made post-
operatively showed a marked progression of the pulmonary
lesions with the left caudal lobe being the only near-normal
lobe. The remaining lobes had an increased fluid content with
a prominent air-bronchogram pattern. Silhouetting with the
heart shadow reflected the amount of fluid content in the
lungs. The dilated esophagus remained evident and continued
to depress the air-filled trachea.
Outcome: The dog subsequently died. At necropsy,
esophageal dilatation plus a secondary inhalation pneumonia
were found. The abdominal exploratory surgery added stress
to the dog and also positioned it in dorsal recumbency for sev-
eral hours, probably adding to the flow of the acid-rich gastric
fluids into the lungs.
Comments: Several errors had possibly been made in the
handling of this patient. First, the importance of the distend-
ed, air-filled esophagus present on the first radiographs was
not appreciated. Second, a second set of pre-operative radio-
graphs was not made due to the assumption that the status of
the lungs would remain static. When radiographs were made
post-operatively, the progression of what was then assumed to
be aspiration pneumonia was evident.
2
Day 6

Case 2.78
Signalment/History: “Fluffy”, a 2-year-old, male DLH cat,
was presented with a history of gagging and regurgitation of
undigested food. If fed liquids, he did not vomit. These find-
ings followed an earlier clinic stay lasting three weeks that had
been required to correct a urinary blockage. He had been
anesthetized during that hospitalization.
Radiographic procedure: Thoracic studies were made with
liquid barium and barium mixed with kibble (dried cat food).
Radiographic diagnosis: The liquid swallow revealed a
small esophageal stricture at the level of C4 (referral and liquid
barium swallow, arrow). The kibble meal allowed a more thor-
ough understanding of the stricture (arrow).
Treatment/Management: The stricture was thought to be
due to an esophagitis as a result of regurgitation during recov-
ery from the anesthesia.
2
Referral

2
Liquid barium swallow
Barium swallow mixed with kibble

Case 2.79
Signalment/History: “Shampoo” was a 10-year-old, male
Labrador Retriever mixed breed with a chronic history of dys-
phagia and regurgitation. He ate only blended food and could
only do that successfully if the food was placed in an elevated
position. The clinical problem had started some days follow-
ing abdominal surgery.
followed by contrast studies using only a liquid barium meal.
Radiographic diagnosis: An air-filled dilated esophagus ex-
tended from the thoracic inlet to the carina, and appeared to
be “wrapped-around” the trachea (arrows). The mediastinum
did not appear to be increased in size. The lungs appeared nor-
mal.
The bolus of barium sulfate showed a persistent proximal
esophageal dilatation with a failure to pass an apparent stric-
ture at the heart base. A portion of the more liquid swallow
passed the constricted segment and flowed into the caudal
portion of the esophagus. The mucosal surface appeared
roughened. The exact nature of the esophageal lesion was not
evident on these studies.
2
Noncontrast

Treatment/Management: Endoscopy was limited to the
cranial portion of the esophagus where granular-type lesions
could be identified within the wall. Fibrotic-like tissue ex-
tended across the esophageal lumen and appeared to act as
strictures. Examination of tissue removed by biopsy was con-
sistent with that resulting from a chronic esophagitis. The
clinical history suggested that the injury to the esophagus
could have been secondary to regurgitation at the time of the
surgery.
2
Contrast

Case 2.80
Signalment/History:“Duke”, a 10-month-old, male Gold-
en Retriever, had a history of difficulty in swallowing. He was
referred following an attempt to perform a contrast study of
the esophagus in another clinic.
Physical examination: The dog was definitely dyspneic
with abnormal lung sounds.
Radiographic diagnosis (day 1): Barium sulfate contrast
agent was seen within the main-stem bronchi of the four lobes
of the right lung and a portion of the left lung. The bronchi
appeared to be ectatic. The barium sulfate had the appearance
of being obstructive and did not extend beyond the 3rd
or 4th
generation of bronchi. No evidence of lung disease could be
seen. A diffuse pattern of barium sulfate remained within a di-
lated segment of the cranial mediastinal esophagus that seemed
to place dorsal pressure on the hilar region.
Note the malposition of the right main-stem bronchi. This
may be a result of hyperinflation of the left lung or could sug-
gest a congenital right lung disease.
2
Day 1

Radiographic diagnosis (day 3): The barium sulfate with-
in the main-stem bronchi remained unchanged from the ear-
lier study except for the progression of the contrast meal into
the left side. The bronchi continued to appear abnormal.
There was no change in the size of the affected lung lobes and
no increase in lung density suggestive of pneumonia or atelec-
tasis. Clearance of the diffuse pattern of barium sulfate in the
esophagus was noted.
Differential diagnosis: Bronchiectasis was suspected as it
could explain why “Duke” could not clear the liquid foreign
body that had been aspirated during the attempted
esophogram. The contrast agent was thick as indicated by its
density and failure to spread distally within the lungs.
The atonic wall of the dilated esophagus suggested chronic
esophageal disease.
The radiographs of this bronchial foreign body clearly show
one of the major problems in the use of contrast agents. Be-
cause the contrast agent appears to be tube-shaped, it is as-
sumed that it is a solid plug; however, it may be only a coat-
ing of barium sulfate on the bronchial wall. That it was indeed
a coating on the wall would explain not only how the passage
of air continued to occur into all of the lobes and why the
lungs failed to become atelectic with absorption of the air, but
also why a pneumonia did not develop.
Treatment/Management: “Duke” was discharged without
any explanation of the radiographic changes.
2
Day 3

Case 2.81
Signalment/History: “Wow” was a 9-year-old, female Ter-
rier with a history of chronic, intermittent vomiting for the
previous six months. She had been given a barium sulfate
upper-intestinal radiographic study at the referring clinic sev-
eral days earlier.
Radiographic procedure: She had thoracic radiographs
prior to anesthesia for a scheduled laparotomy.
Radiographic diagnosis: Alveolarization of barium sulfate
was primarily in the caudal lung lobes. No pulmonary masses,
pleural fluid, or mediastinal shift were evident. No changes
were present in the thoracic wall. The diaphragm was in its
normal location. A spondylosis deformans typical for a dog of
this age was also apparent.
Treatment/Management: Inhalation of barium sulfate sus-
pension is not a life-threatening event when it is alveolarized
and distributed widely as in this dog.
Differential diagnosis: In the absence of the clinical history
in a case such as this, other causes of diffuse alveolar densities
include several chronic diseases such as inhalation of powdered
mineral material. This creates a radiographic pattern because
of its density. Other inhaled materials such as asbestos or pow-
ered plant material could result in a secondary, alveolar min-
eralization throughout the lungs that might appear similar to
the barium sulfate in this case.
2

2.2.13 Tracheal/bronchial foreign bodies
Case 2.82
Signalment/History: “Tuffy” was a mature, male DSH cat
with a history of acute onset of coughing and dyspnea that was
intermittent in severity.
Physical examination: Observation of the cat clearly
showed a difficulty in breathing that changed in nature.
thorax.
Radiographic diagnosis: A radiopaque foreign body filled
the lumen of the trachea at the tracheal bifurcation. No in-
flammatory response was noted around the foreign body and
the lung lobes did not show any signs of either obstructive at-
electasis or obstructive emphysema.
Treatment/Management:A rock was removed through the
use of bronchoscopy and “Tuffy” was discharged. Note the
difficulty in identifying the foreign body on the DV view,
even though it had a high tissue density.
Comments: A comparison of inspiratory and expiratory tho-
racic radiographs is valuable in determining the obstructive
nature of a tracheal foreign body.
Tracheal/bronchial foreign bodies 165
2

Case 2.83
2

Signalment/History: “Mia” was an 8-year-old, female Aus-
tralian Cattle dog who had been attacked by four dogs the day
before. She had received supportive care at an emergency hos-
pital and was transferred to this hospital with severe bite
wounds.
Physical examination: The dog had severe skin lesions;
some of which had been treated surgically. More interesting
was the dog’s pattern of breathing that suggested a partial air-
way obstruction.
Radiographic procedure: Because of the respiratory signs,
radiographs were made of the thorax. The stifle joint was also
radiographed because of the bite wounds.
Radiographic diagnosis (thorax): A circular, sharply de-
fined, radiodense object lay within the lumen of the right cra-
nial main-stem bronchus and was suspected to be a foreign
body (arrows). The remaining pulmonary structures were
within normal limits. The cardiovascular structures were
within normal limits. Subcutaneous emphysema in the soft tis-
sues on the right lateral cranial thorax was prominent. The ap-
pearance of the foreign body varied according to which side
of the patient was dependent at the time of radiography.
Radiographic diagnosis (stifle joint lateral view): A se-
vere soft tissue injury with subcutaneous emphysema involved
the left pelvic limb. It had been treated with gauze pads iden-
tified by radiopaque markers. A rubber Penrose drain was near
the stifle joint. No evidence of bone or joint injury could be
seen.
Treatment/Management: The bronchial foreign body in-
fluenced the clinical signs of this patient, but it is somewhat
difficult to relate it to the traumatic incident. It is possible the
foreign body had been present for some time without causing
an obstruction, although it had stimulated a chronic bronchi-
tis. The peribronchial shadows are more prominent than ex-
pected although “Mia” was 8 years of age and the prominence
of the airway shadows can be age related.
Comments: Examine the pulmonary vessels and judge if the
dog is in shock.
2

Case 2.84
Signalment/History: “Ginger” was a 7-year-old, female
German Shepherd who had had an acute onset of wheezing
and coughing seven days earlier. She had been treated system-
atically for the past week and then referred for further exami-
nation.
Physical examination: A cough could be elicited by palpa-
tion of the cervical trachea.
thorax.
Radiographic diagnosis: A radiodense foreign body with
a density similar to that of bone was present just proximal to
the carina (arrows). No evidence of bronchial obstruction was
noted.
Treatment/Management: The foreign body was removed
by bronchoscopy. Note the more coarse lung markings in this
older dog are probably the result of chronic airway disease
(bronchitis). Prominent skin folds lay across the ventral thorax.
2

Signalment/History: “Jenny”, a 1-year-old, female DSH
cat, had been subjected to elective surgery and was in recov-
ery, when it was noted that the endotracheal tube, which had
not been previously removed, had been chewed in half.
Radiographic procedure: A single lateral view of the cer-
vical region and thorax was made.
Radiographic diagnosis: A portion of the endotracheal
tube was located in the distal portion of the trachea (arrows).
Comments: Positioning of the forelimbs in this manner
makes it possible to evaluate both the cervical and thoracic
segments of the trachea.
Case 2.85
2

Case 2.86
Signalment/History: “Muffet” was a 3-year-old, female
DHL cat with a three- to four-day history of a harsh cough.
Physical examination: The lungs were difficult to auscul-
tate. The abdomen on physical examination was distended
with gas-filled bowel loops.
Radiographic procedure: The thorax was radiographed be-
cause of the clinical signs.
Radiographic diagnosis: A radiopaque, mid-cervical, freely
movable tracheal foreign body was present, most probably a
pebble (arrows). The hyperinflated lung fields were an indica-
tion of the partially obstructive nature of the foreign body.
The gas-filled cranial esophagus and distended stomach were
possibly stress related.
Treatment/Management: An upper airway foreign body
can function as a valve permitting the passage of air in only
one direction. In “Muffet”, it appears as though the pebble
permitted air to pass into the lungs, but it at least partially ob-
structed the trachea on expiration resulting in an obstructive
emphysema.
The free movement of the foreign body could be ascertained
by a comparison of the location of the object on the two
views. This movement could result in changeable clinical signs
with the foreign body being obstructive only part of the time.
2

Signalment/History: “Raja” was a 2-year-old, male
Siamese cat that had been struck by a car two weeks previous-
ly. He then had began to show both an inspiratory and an ex-
piratory dyspnea that became more severe. Earlier radiographs
were not available for examination.
Physical examination: He was difficult to examine because
of the dyspnea.
thorax.
Radiographic diagnosis: A tracheal stenosis was identified
by an interruption in the pattern of the air-filled intratracheal
shadow at the level of T3–4. A pneumomediastinum report-
ed on earlier radiographs was no longer present.
Treatment/Management: At the time of surgery, a 1–2 cm
long fibrous band extended between the torn ends of the tra-
chea. This tube-like structure was removed and a tracheal
anastomosis was performed. Post-surgical radiographs showed
a trachea with a lumen of normal width.
Comments: The studies were limited to lateral views because
of the difficulty in visualization of the trachea on the DV/VD
views. It is possible to make VD oblique views to provide
additional information about the trachea.
Case 2.87
2

Signalment/History: “George” was an 11-year-old, male
DSH cat with a four-week history of coughing, wheezing,
and dyspnea. These symptoms were partially responsive to
prednisone therapy. Previous endoscopy had shown an ede-
matous larynx and biopsy revealed a laryngeal polyp.
Physical examination:Increased respiratory stridor was not-
ed on physical examination with an increased expiratory ef-
fort. Palpation of the trachea and larynx, as well as an oral ex-
amination were unremarkable. An intrathoracic obstructive
lesion was suspected.
Radiographic procedure: Lateral views were made of the
cervical region and a complete study of the thorax.
Radiographic diagnosis: Indistinct shadows in the terminal
trachea and carina suggested a tracheal foreign body or mass
(arrows). The mediastinum had a greater fluid density over the
base of the heart. The diameter of both the extrathoracic and
intrathoracic trachea was small. The lungs were hyperinflated
without infiltrative or pulmonary mass lesions. The minimal
peribronchial shadows were compatible with the age of the pa-
tient. The diaphragm was caudal and flattened. The patient
was noted to be obese. The spondylosis deformans present was
compatible with the cat’s age. A metallic air-gun pellet lay in
the soft tissues ventral and to the left of the rib cage.
Case 2.88
Treatment/Management: Bronchoscopy revealed a small
(0.5 x 1.0 cm), flat rock covered with casseous exudate at the
level of the carina. Following removal of the foreign body,
“George” was placed on Clavamox for 10 days to prevent ex-
tension of the secondary bacterial infection. He was then dis-
charged with resolution of his dyspnea.
Comments: It is considered poor medical practice to treat a
patient with a history of respiratory distress for four weeks
without making a radiographic study of the thorax.
2

2

Case 2.89
Signalment/History: “Smoochy”, a 7-year-old, female
DSH cat, was presented with a history of having had a bron-
choscopy examination two weeks previously in search of a
tooth that was thought to have been inhaled.
Radiographic procedure: The radiographic examination
was a search for the missing tooth.
Radiographic diagnosis (day 1): A radiopaque foreign
body was located in the right, main-stem bronchus to the cau-
dal lung lobe and had the appearance of a tooth. Minimal lung
congestion with the appearance of a plate-like atelectasis was
evident distal to the obstruction. The minimal mediastinal
shift to the right was probably due to the atelectasis. The re-
maining lung fields were normal.
2
Day 1

Radiographic diagnosis (day 2): The previously identified
radiopaque foreign body had been removed. The lung con-
gestion distal to the site of the foreign body was less promi-
nent. A static left-sided cardiomegaly was evident.
Comments: The foreign body appeared to be slightly ob-
structive causing atelectasis of the right lung and compensatory
hyperinflation of the left lung. This imbalance had been cor-
rected by the time of the second study.
2
Day 2

Case 2.90
Signalment/History: “Bruce” was a 1-year-old, male DSH
cat with an acute onset of “gagging”.
Physical examination: The rate of respiration was increased
and a marked expiratory effort was noted.
Radiographic procedure: Routine studies were made of
the thorax.
Radiographic diagnosis (day 1): An increase in fluid den-
sity within the left caudal lung lobe was associated with a
mediastinal shift to the left. This appeared to be an obstructive
atelectasis and could have been associated with a bronchial for-
eign body. The air-filled trachea was truncated at the hilar re-
gion as seen on the lateral view. The failure to see the normal
air-filled carina supported the diagnosis of an intratracheal for-
eign body.
Treatment/Management: The foreign body was a plant
head and it was removed from the left main-stem bronchus us-
ing a bronchoscope.
2
Day 1

Radiographic diagnosis (day 2, post surgery): The re-
inflation of the obstructed lobe had occurred in the previous
two days. The mediastinal shift was no longer present, and the
appearance of the hilar region was normal.
2
Day 2, post surgery

2.2.14 Tracheal injury
Case 2.91
2
Day 1
Day 8

Signalment/History: “Tina” was a 2-year-old, female Pit
Bull Terrier mixed breed with a history of having been in a
fight with another dog one month earlier. She had difficulty
in swallowing, which had begun at the time of the fight and
she had vomited partially digested food at times since then,
unassociated with eating. Her breathing was difficult.
The radiographic interpretation of the thorax one month pre-
viously showed the lungs to be poorly inflated resulting in an
increase in both interstitial and peribronchial density.
Radiographic procedure: Because of the history of a bite
wound to the neck, the radiographic study was directed to-
ward that region.
Radiographic diagnosis (day 1, cervical region): The
tracheal stenosis was 1 cm in length and involved 5 or 6 tra-
cheal rings at the level of C5. The lesion was probably post-
traumatic.
Radiographic diagnosis (day 8 post surgery, cervical
region): The lumen of the stenotic segment was wider and
was almost 2/3 of its normal diameter. A ring of soft tissue pro-
truded into the tracheal lumen at the level of C5. The ventral
soft tissue edema was probably postsurgical.
Radiographic diagnosis (day 23, cervical region): The
diameter of the post-traumatic tracheal stenosis was almost
normal and the ring of intraluminal soft tissue at level of C5
had almost completely regressed.
Treatment/Management: The surgical biopsy revealed
fractured tracheal rings with one ring protruding into the lu-
men being the primary cause for the stricture. The broken
rings were calcified forming a cartilaginous callus around the
trachea.
It is interesting that the clinical signs had suggested a problem
with swallowing; however, the immediate treatment was di-
rected toward the tracheal stenosis. The possibility of adjacent
esophageal injury would indicate the need for study of that or-
gan as well.
Tracheal injury 179
2
Day 23

2.2.15 Esophageal foreign bodies
Case 2.92
2
Noncontrast

Signalment/History: “Tina Maria” was a 14-year-old, fe-
male Miniature Poodle with a clinical history suggestive of an
esophageal foreign body for the previous three weeks.
Physical examination: The dog was alert but thin with al-
most no body fat.
Radiographic procedure: Both non-contrast and contrast
studies were performed in an evaluation of the esophagus.
Radiographic diagnosis: A radiodense esophageal foreign
body with the marginal features and density of a bone was lo-
cated just dorsocranial to the heart (arrow). No air or fluid was
noted within the mediastinum as would have been expected if
the esophageal wall had been punctured. Tracheal elevation
was associated with bilateral cardiomegaly.
The barium sulfate swallow confirmed the location of the for-
eign body and showed no leakage of the contrast agent. The
foreign body was not obstructing and permitted fluid to pass,
thus enabling the patient to survive during the previous three
weeks.
Treatment/Management: The bone was removed surgical-
ly; however, the patient died one day later. At necropsy, the
esophagus had a single perforation 1 mm in diameter at the site
of the foreign body. The trachea also had a 1 mm in diameter
hole in the center of the inflammatory response at the same lo-
cation. These findings support the clinical history of the for-
eign body having been present for three weeks and indicate
the nature of the secondary changes that can occur in the event
of failure to remove a foreign body promptly, especially if it
has sharply protruding parts that can penetrate the esophageal
wall.
Comments: Unfortunately, a focal mediastinitis cannot usu-
ally be identified on a radiographic study of the esophagus,
with or without contrast agent, because the pocket of in-
flammation closes the sites of penetration and does not alter
the appearance of the esophagus, trachea, or surrounding
mediastinum. Even if air should escape through the site of
penetration, the amount is usually so minimal that it cannot be
recognized on a radiograph.
Esophageal foreign bodies 181
2
Barium swallow

Signalment/History: “Abby” was a 3-year-old, female
mixed breed who had been intermittently retching after hav-
ing eaten a “rawhide bone” eight days earlier. Referral radio-
graphs were available for examination.
Radiographic diagnosis (day 1, referral lateral view
only): An increase in fluid density in the dorsocranial medi-
astinum suggested the presence of a radiolucent esophageal le-
sion, possible a foreign body. A localized mediastinitis associ-
ated with the lesion could explain the presence of some of the
fluid. No evidence of a pulmonary lesion was noted.
only): The mediastinal mass had a similar appearance as on
day 1.
only with barium sulfate swallow): The contrast swallow
identified a linear intraluminal object within the distended
esophagus over the heart base. A part of the swallow had passed
into the stomach.
Case 2.93
2
Day 1

2
Day 3
Day 3, barium swallow 왘왘

Radiographic diagnosis (day 4, referral DV and lateral
view): The liquid density mass over the heart base was un-
changed. However, collapse of the right cranial lobe with an
air-bronchogram pattern was indicative of collapse due to as-
piration pneumonia or an obstructive atelectasis associated
with an extrabronchial mass.
Treatment/Management: The pulmonary lesion compro-
mised what might have been a simple esophageal foreign body
and suggests penetration or a periesophageal inflammatory le-
sion. “Abby” died shortly after surgical removal of the
esophageal foreign body due to a ruptured esophagus. It was
not clear from the clinical record why surgical removal of the
foreign body had been delayed.
2
Day 4

Case 2.94
Signalment/History: “Boscoe” was a mature female Beagle
with a history of repeated attempts to regurgitate food.
Radiographic procedure: Whole-body radiographs were
made to look for a foreign body.
Radiographic diagnosis: A radiopaque esophageal foreign
body lay within the caudal aspect of the esophagus. The lung
fields were within normal limits.
Treatment/Management: A bottle cap was withdrawn
from the esophagus using a retractor.
2

Case 2.95
2
Without esophageal tube

Signalment/History: “Muggy” was a 5-month-old, male
Lhasa Apso who had swallowed a fishhook.
Radiographic procedure: Radiographs included the cervi-
cal esophagus.
Radiographic diagnosis: The first radiographs showed the
hook at the thoracic inlet with the point more distal. The VD
view showed the cranial mediastinum was widened, but a
puppy this age has a persistent thymus gland that can prove dif-
ficult to differentiate from mediastinal thickening secondary
to injury.
A second study was made with an esophageal tube in position.
The hook had turned but not moved, suggesting that it was
fixed in position.
Treatment/Management: An unsuccessful attempt was
made to retract the hook with the result that it was driven
firmly into the esophageal wall. It was then removed on a sub-
sequent attempt using an endoscope.
2
With esophageal tube

2.2.16 Esophageal injury
Case 2.96
Signalment/History: “Pia”, a 1-year-old, female Queens-
land Heeler, was presented with acute signs of vomiting and
discomfort.
Physical examination: Following examination, the tenta-
tive diagnosis was that of a diaphragmatic hernia. However,
the presence of subcutaneous emphysema did not exactly fit
that diagnosis.
and cervical region. These were followed by a barium swallow.
Radiographic diagnosis (noncontrast): Subcutaneous
emphysema and pneumomediastinum made evaluation of the
infiltrative pattern throughout the lung fields difficult to eval-
uate. The mediastinum was increased both in depth and
width, suggesting an accumulation of mediastinal fluid associ-
ated with a mediastinitis. The cause of the mediastinal air and
fluid could not be determined. The cardiac silhouette was
shifted to the right perhaps influenced by the VD positioning.
The diaphragm was intact on both views.
2
Noncontrast

Radiographic diagnosis (barium swallow): The liquid
contrast agent was injected through a tube with its tip lying in
the proximal portion of the esophagus. The liquid immediate-
ly leaked into the periesophageal tissues on the left side and
into the mediastinum. Leakage of this magnitude indicated an
extensive tear in the wall of the esophagus (arrows).
Treatment/Management: “Pia” died shortly after the ex-
amination and the owners prevented a necropsy examination.
It was thought that the dog had received a severe bite wound;
however, the owner refused to support this possibility.
Esophageal injury 189
2
Barium swallow

Signalment/History: “Hastey Hattie” was a 1-year-old,
male mixed breed cat that had been experiencing vomiting
immediately after eating solid food for the previous four
weeks.
Radiographic procedure: Studies of the thorax were fol-
lowed by contrast studies including both liquid and solid swal-
lows.
Radiographic diagnosis: An esophageal stricture was indi-
cated by identification of a narrowing of the lumen that per-
mitted passage of the liquid swallow. The esophageal meal
identified the lesion more clearly with the failure of the solid
food to pass through it.
Treatment/Management: The studies made with the liquid
meal showed passage through the site of stricture with only a
suggestion of a hold-up at the level of C6–7. The studies made
with the liquid agent mixed with normal cat food created a
bolus that was unable to pass through the site of esophageal
stricture at C6–7 (arrows). It caused a dilation of the proximal
esophagus until such a time when the cat regurgitated the bo-
lus. The owners refused treatment and promised to control the
nature of the food given to the cat.
Case 2.97
2
Liquid barium swallow

2
Solid barium swallow

Case 2.98
Signalment/History: “Chu” was a 6-month-old, male
Sharpei with a history of post-prandial vomiting over the pre-
vious few days. An esophageal obstruction was suspected be-
cause of “toys” that were missing from the home.
Radiographic procedure: Routine thoracic studies were
made followed by a positive contrast esophagram.
Radiographic diagnosis (thorax): Two large sharply mar-
ginated, thin-walled, fluid and air-filled saccular structures
with two separate compartments were noted within the cau-
dal thorax dorsally on the midline. It was thought they repre-
sented air-filled caudal mediastinal masses. The caudal trachea
was displaced ventrally supporting the diagnosis of a mediasti-
nal mass. The right caudal lobe bronchus was shifted laterally
and ventrally with minimal collapse. A bronchial pattern
caused the presence of “ring signs” and “tram lines”. The ribs
were expanded markedly. Skin folds falsely suggested a pneu-
mothorax on the DV view.
2
Noncontrast

Radiographic diagnosis (esophagram): A gastric hiatal
hernia of the fundic portion of the stomach was identified fol-
lowing the use of a double contrast study with barium sulfate
mixed with air. It extended cranially to the level of T7. Rugal
folds were seen extending across the line of the diaphragm
confirming the hernia. An increased density of the accessory
lung lobe suggested aspiration pneumonia plus a possible at-
electasis. The dog’s swallowing function was normal under
fluoroscopy; however, the esophagus was redundant at the
thoracic inlet and caudal to the heart shadow.
Comments: Conducting the radiographic study was compli-
cated by difficulty in positioning of the patient and there was
a question of whether the saccular structure was filled with
fluid or air. The bronchial pattern indicated probable chronic
aspiration with secondary chronic bronchitis.
2
Esophagram

Case 2.99
Signalment/History: “Widgie”, a 4-month-old, male
Sharpei, was presented with a history of anorexia for two
weeks. It was suspected that he had been “bothered” by dogs
belonging to the neighbors. The dog was in acute depression,
hypothermic and in shock.
thorax.
Radiographic diagnosis (noncontrast): A large, sharply
marginated soft tissue density mass in the right hemithorax
was located dorsally with a portion appearing to extend into
the caudal left hemithorax. The mass was thought to be a pul-
monary mass or a caudal mediastinal mass. In addition, there
was a widening of the cranial mediastinum. The bronchus to
the accessory lobe was displaced laterally and an air-bron-
chogram pattern in the right caudal lobe suggested pneumonia
or an atelectic lobe. The bronchial pattern in the left cranial
lobe suggested chronic inhalation. The prominent skin folds
were typical for the breed.
2
Noncontrast

Radiographic diagnosis (esophagram): A gastric hiatal
hernia of the fundic portion of the stomach with rugal folds ex-
tending into the thoracic cavity was identified. The increased
density of the accessory lung lobe was more clearly defined sug-
gesting aspiration pneumonia and/or atelectasis. The lateral
displacement of the left accessory lobe bronchus was apparent
as in the noncontrast study. The formation of a bolus and its
passage to the thoracic inlet was normal under fluoroscopy. A
redundant esophagus began at the thoracic inlet, with the dilat-
ed esophagus extending caudally to heart.
Treatment/Management: The lesion in “Widgie” had an
unusual radiographic appearance since it was fluid-filled. This
made the possibility of a solid tumor-like mass more likely.
“Widgie” responded successfully to treatment for shock while
hospitalized. He was not operated immediately and the aspira-
tion pneumonia was ignored. When he began to vomit blood
four days later, he was euthanized at the owner’s request.
At necropsy, the entire stomach, left lateral liver lobe, the pap-
illary process of the caudate liver lobe, and the spleen were her-
niated into the thoracic cavity. A 2-cm-in-diameter erosion
was found on the mucosal surface of the stomach and may have
been the source of the acute hemorrhage. The extensive herni-
ation of abdominal contents was not noted on the original ra-
diographs and appeared to have been acute. Severe secondary
aspiration bronchopneumonia was detected at necropsy.
Comments: “Widgie” should have been operated on sooner.
2
Esophagram

Case 2.100
Signalment/History: “Shammie” was a 5-year-old, female
Toy Poodle with an acute history of coughing and vomiting.
The referral diagnosis was an esophageal foreign body with a
secondary bronchitis/pneumonia.
Physical examination: The examination provided little in-
formation.
Radiographic procedure: Routine thoracic radiographs
were followed by an esophagram that included a fluoroscopic
examination.
Radiographic diagnosis (noncontrast): A large sharply
defined, thin-walled mass was located in the dorsocaudal right
hemithorax. The mass contained a granular-like pattern sug-
gestive of ingesta mixed with air. The mass was thought prob-
ably not to be pulmonary.
As a result of the mass, there was a ventral displacement of the
carina. There was also a slight infiltrative pattern within the
left caudal lung lobe that could have been due to pneumonia.
The cardiac shadow was within normal limits. The air-filled
gastric shadow was within the abdominal cavity as was the liv-
er. The right hemidiaphragm was flattened and was located
caudal to the left hemidiaphragm. No evidence of thoracic
wall injury was noted. The air-filled stomach suggested panic
breathing.
2
Noncontrast

Radiographic diagnosis (contrast study, VD views
only): The fluoroscopic examination and esophagram
demonstrated a generalized esophageal dilatation with promi-
nent caudal esophageal sacculation. The gastroesophageal
junction was located in its normal position. The barium sul-
fate entered the stomach under fluoroscopic control; however,
the dilated esophagus exhibited only weak peristaltic activity.
The gastro-esophageal junction was again noted to be in a
normal position.
Treatment/Management: “Shammie” was operated. The
caudal esophagus was a “bladder-like” structure 3 x 4 cm in
diameter with walls that were 2–4 mm thick. This structure
was removed surgically with closure of the esophageal defect.
The esophagus was adherent to the surrounding lung lobes
making removal of the right caudal and accessory lobes neces-
sary. Postsurgical hemothorax coupled with pre-existing
pneumonia resulted in cardiac arrest immediately after the sur-
gery, resulting in the death of the patient.
The etiology of the esophageal diverticulum was not deter-
mined.
Comments: Note that the intrathoracic mass did not fit the
shape or position of any of the lung lobes and is therefore not
likely to be of pulmonary etiology. On several of the studies,
the right caudal bronchus was markedly displaced laterally.
The mixed pattern of air and fluid density was unlike that
found in pulmonary disease. This lesion fitted a diagnosis of an
esophageal diverticulum. The radiographs were over-exposed
and were not of maximum value in the determination of lung
disease.
2
Contrast

3.1 Introduction
3.1.1 The value of abdominal radiology
Radiology is a diagnostic tool used in the investigation of ab-
dominal trauma, which can be easily performed in an inex-
pensive, quick, and safe manner, providing rapid results on
which to base decisions relative to diagnosis and/or treatment.
The x-ray image allows the visulisation of the abdominal or-
gans if the abdominal fat provides sufficient contrast. Good
contrast outlining the location and status of the gastrointesti-
nal organs can also be provided by air, ingesta, and feces con-
tained in the hollow organs. Radiographic contrast studies
permit the evaluation of both the gastrointestinal and urinary
tracts, either anatomically or functionally.
The radiographic evaluation of abdominal radiographs of a
traumatized patient should be performed in an organized man-
ner and include the systematic examination of all the anatom-
ic structures including the peripheral soft tissues, surrounding
bony structures, retroperitoneal space, peritoneal cavity,- in
addition to the solid abdominal organs, and the hollow viscera.
3.1.2 Indications for abdominal
radiology
The abdominal organs are thought to be more vulnerable to
trauma than the thoracic organs probably because they are not
protected by a bony case. Iatrogenic trauma can result from
perforation due to the passage of a urinary catheter or follow-
ing endoscopy, organ laceration following paracentesis, inad-
vertent ligation during surgery, or the development of post-
surgical strictures or adhesions. The rupture of abdominal
organs in trauma patients can result in peritoneal hemorrhage,
bacterial peritonitis, bile peritonitis, uremic peritonitis, or
pancreatitis, all of which can create a similar radiographic
pattern. Abdominal injury due to trauma may be limited, but
often it involves injury to the intrathoracic structures, di-
aphragm, vertebrae, and pelvis as well (Table 3.1).
The clinical situations suggesting the need for abdominal radi-
ography include: (1) patients with a known or suspected ab-
dominal trauma, (2) patients who are vomiting, (3) patients
who are not producing urine, (4) patients in shock, and (5)
trauma patients prior to surgery.
Table 3.1: Injury to specific abdominal organs secondary to trauma
may include
1. Body wall (Cases 3.12, 3.13, 3.14, 3.15, 3.16 & 3.19)
a. laceration
b. perforation
c. herniation
2. Abdominal organs
a. liver – displacement, rupture, subcapsular hemorrhage, herniation,
lobe avulsion (Cases 2.32, 2.42, 2.50, 2.51, 2.99 & 2.100)
b. gall bladder – rupture, avulsion, herniation (Cases 2.9 & 2.51)
c. spleen – torsion, subcapsular hemorrhage, herniation, rupture
(Cases 2.16, 2.42 & 2.99)
d. pancreas – rupture (Case 2.9)
e. stomach – herniation, rupture, volvulus, aerophagia (Cases 2.14, 2.99,
2.100, 3.3 & 3.4)
f. bowel – herniation, mesenteric torsion/volvulus, perforation/rupture,
infarction, obstructive ileus, paralytic ileus (Cases 2.9, 2.42, 2.51, 3.10,
3.13, 3.16, 3.18 & 3.22)
g. kidney – subcapsular hemorrhage, rupture, avulsion, acute
hydronephrosis, renal artery injury (Cases 2.50, 3.20, 3.24 & 3.35)
h. ureter – rupture, acute hydroureter, avulsion (Cases 3.20, 3.23, 3.24,
3.29 & 3.35)
i. urinary bladder – rupture, intramural hemorrhage, intraluminal
hemorrhage, avulsion, herniation, retained catheter (Cases 3.18, 3.19,
3.20 & 3.21)
j. urethra – avulsion, rupture, foreign body (Cases 3.12, 3.22, 3.25, 3.26,
3.27, 3.28, 3.29 & 3.30)
k. prostate gland – herniation (Case 3.20)
l. mesentery – tear, herniation, torsion (Cases 2.16 & 3.36)
m. uterus (Cases 2.43, 3.31 & 3.34)
The clinical signs of patients with abdominal trauma can vary
from profound shock due to blood loss to those showing only
lameness due to an associated musculoskeletal injury. A care-
ful physical examination may be able to determine injuries in
addition to those clinically apparent.
3.1.3 Radiographic evaluation
of abdominal radiographs
first technique is to “memorize” the appearance of all disease
or pathologic changes that might be found in a traumatized ab-
domen, and then examine the radiograph looking carefully for
those changes. An approach of this type is taken by tradition-
al textbooks of medicine, in which diseases are presented with
a description and an illustration of the typical radiological ap-
pearance. The difficulty with this approach is similar to the
difficulty found in applying textbook knowledge to the reali-
ty of a sick animal. Clinical information of the traumatized
3
Chapter 3
Radiology of Abdominal Trauma

patient is often indefinite and ambiguous. It is the same with
the information available from a radiograph. In many patients,
the radiological picture of a disease is not “typical”, and the
textbook approach therefore may lead to confusion or mis-
diagnosis.
A more accurate method of radiographic evaluation uses the
identification of particular radiographic “signs” or “features”
that are indicative of pathophysiologic changes, and an under-
standing of the diseases in which such signs or features are
known to occur. The number of these signs is much less in ab-
dominal radiography than in thoracic radiography.
Any successful examination of a radiograph must be systemat-
ic in order to ensure that all parts of the radiograph are com-
pletely examined. The best system is anatomical and includes
the conscious examination of each anatomical structure with-
in a given region in the body. Start the radiographic examina-
tion by evaluating the gastrointestinal tract. The stomach
usually contains either air and/or ingesta permitting its iden-
tification. The duodenal loop often contains air and is located
against the right abdominal wall on the DV view and lies
within the midabdomen on the lateral view. Small bowel
shadows are scattered in a nondescript pattern. In contrast, the
cecum and colon are specific in location and can be identified
by the presence of feces.
Identification of the ventral liver margin and adjacent splenic
shadow is often incomplete and is dependent on the fat with-
in the falciform ligament. The margin of the head of the
spleen is best seen lateral to the stomach shadow on the
DV/VD projection. The renal shadows can be clearly seen if
the perirenal fat provides sufficient contrast. The urinary
bladder is identified more easily if it is partially distended.
Overlying small bowel and colonic shadows may make iden-
tification of the bladder difficult or impossible.
Study of the periphery of the abdomen should include the di-
aphragm, vertebrae, pelvis, perivertebral space, abdominal
musculature, and the pelvic inlet. Spurious or artifactual radi-
ographic changes seen in the abdominal wall include shadows
caused by nipples, skin nodules, skin folds, wet hair, dirt, and
bandaging material. Subcutaneous fluid, subcutaneous air, and
subcutaneous fat alter the appearance of the abdominal wall.
These vary widely, being dependent on the patient and the na-
ture of the injury.
The stage of respiration has little effect on the radiographic ap-
pearance of the abdomen, although it is better to make the ex-
posure on expiration, when the abdominal cavity is at its
greatest size. As a consequence, the diaphragm is more cranial
and convex and has greater contact with the heart on expira-
tion than inspiration. This position results in a superimposi-
tion of a part of the heart shadow over the diaphragm. A
portion of the caudal lung lobes can be identified on most
abdominal radiographs.
3.1.4 Radiographic features in
abdominal trauma
Positioning of the patient influences the appearance of the ab-
dominal organs. In certain trauma patients, the manner of po-
sitioning is determined by the nature of the injury. In others,
positioning can be selected for the radiographic study that is
felt to offer a better opportunity of evaluating a particular ab-
dominal organ. For example, in a dog with a known abdomi-
nal injury it is possible to consider placing the injured area
next to the tabletop in an effort to achieve the smallest object-
film distance. However, in the event of a suspected spinal frac-
ture, it may be better to use a DV positioning and not risk
fighting with the patient to obtain a view in which the spine
would be next to the tabletop, thereby causing further injury
to the spine. It is not possible to make any firm recommenda-
tions in the case of trauma patients, though the effect of posi-
tioning on the appearance of the organs in the differing posi-
tions needs to be understood before an interpretation is made
(Table 3.2).
Table 3.2: Effect of positioning on the appearance of abdominal
radiographs
1. Left side down, lateral view
a. the gastric gas bubble moves into to the pyloric antrum and the
duodenum is located in the ventral portion of the cranial abdomen
b. the left crus of the diaphragm is more cranial.
2. Right side down, lateral view
a. the gastric gas bubble moves into the fundus of the stomach located
dorsally just caudal to the left crus
b. the right crus of the diaphragm is more cranial.
3. Dorsoventral view
a. the gastric gas bubble fills the dorsal portion of the fundus of the
stomach creating a circular shadow on the left side of the abdomen
in contact with the left crus
b. the separation between the cupula and the dorsal crura is shorter and
often is a distance of the length of 1–2 vertebral bodies
4. Ventrodorsal view
a. the gastric gas bubble occupies the pyloric antrum creating a linear
pattern that crosses the midline
b. the separation between the cupula and the dorsal crura is longer and
often is a distance of the length of 2–3 vertebral bodies
Radiographic features in abdominal trauma 199
3

3.1.4.1 Peripheral soft tissue trauma
The muscles of the abdominal wall can be identified radi-
ographically because the layers of fat adjacent to the peri-
toneum and between the muscle layers all provide good tissue
contrast. The pattern seen on the radiograph varies widely de-
pendent on the obesity of the patient. This tends to make
identification of the muscles easy and any injury to the ab-
dominal wall that results in edema/hemorrhage accumulation
tends to cause a blending of the muscle layers together on a ra-
diograph. Indeed, the radiographic diagnosis of edema or
hemorrhage in the abdominal wall is made by the failure to
easily identify the normal radiolucent muscle stripes. In addi-
tion, the abdominal wall may contain gas shadows with the gas
lying free within the layers of the abdominal wall or just be-
neath the skin following a puncture wound. A major form of
peripheral soft tissue trauma is organ herniation with displace-
ment of solid abdominal viscera outside the abdominal cavity
through a diaphragmatic, paracostal, inguinal, perirenal, ven-
tral, or umbilical tear or rupture. If air- or ingesta-filled bow-
el loops are herniated, their identification is relatively easy to
make on the radiograph regardless of the location of the her-
niation. In comparison, if solid parenchymatous organs are
herniated, the ability to identify them is dependent on the
contrasting surrounding tissue environment. For example, if
the spleen is paracostal and surrounded by contrasting sub-
cutaneous fat, it will be visible on the radiograph, whereas if
the liver is intrathoracic and surrounded by pleural fluid, it will
not be possible to identify it radiographically.
Often soft tissue swellings are detected on physical examina-
tion and suggest the possibility of hernia, but such findings on
palpation need to be differentiated from hematomas, seromas,
or freely moving blood/or edema. The use of oral contrast
agents assists in the identification of herniated bowel, while
the use of intravenous urographic contrast agents assists in the
localization of a herniated urinary bladder.
3.1.4.2 Fractures
The detection of fractures of the surrounding bony structures
can suggest trauma to the adjacent abdominal viscera. A pa-
tient with a rupture of the urinary bladder or urethra can have
an associated pelvic or lumbosacral fracture/luxation. Frac-
ture/luxations of the vertebrae in conjunction with abdomi-
nal injury can be overlooked because of their not causing any
obvious or detectable neurologic signs or problems in loco-
motion at the time of trauma.
3.1.4.3 Peritoneal fluid
There are numerous causes of peritoneal fluid. The fluid can
result from hemorrhage and be due to laceration or crushing
of the liver, gall bladder, spleen, pancreas, or kidneys; though
it is possible the fluid may only be irritative in its etiology. A
uremic peritonitis can follow rupture of the urinary bladder or
injury to the urethra or ureter at the bladder neck. An addi-
tional source of peritoneal fluid results from volvulus, torsion,
or incarceration of the bowel. It is possible for the peritoneal
fluid to become infected because of bowel wall injury and the
fluid may even be grossly septic due to the rupture of a hol-
low viscus or following a puncture wound with a lesion
through the abdominal wall.
It is usually not possible to determine the character of peri-
toneal fluid from a radiograph. However, certain generaliza-
tions can be made. The larger the quantity of fluid, the more
likely it is to be effusive or urine. The more focal it is, the
greater is the possibility that the fluid is septic or hemorrhag-
ic. Paracentesis can be helpful in making a determination of
the nature of the fluid.
The detection of peritoneal fluid can be a difficult radi-
ographic finding and depends on the distribution of the fluid
in the abdomen and the amount present (Table 3.3). A large
quantity of fluid that is distributed throughout the abdomen
causes abdominal distention with a marked loss of contrast, so
that the serosal surfaces of the bowel loops can no longer be
identified. If there is a large quantity of fluid, it comes into
contact with the urinary bladder, liver, spleen, and abdominal
wall making it impossible to identify these normally easily
identifiable structures. With a large amount of fluid, bowel
loops tend to “float” and be separated from each other. It is
difficult to move fluid within the peritoneal space to improve
radiographic diagnosis and thus, there is little value in using
positional radiographic techniques. This contrasts markedly
with the value in observing the movement of fluid within the
pleural cavity.
If the volume of fluid is small, or is localized, the radiograph-
ic diagnosis is even more difficult. This diagnostic problem
can occur with suspected pancreatic injury where the pancre-
atitis is localized or in a focal injury to the bowel with a local-
ized septic peritonitis. Compression studies, if performed
gently, can be helpful in moving normal abdominal structures
away from the site of injury to enhance visualization of the
traumatized organ. Identification of a foreign body within the
peritoneal cavity can be made easier using compression that
shifts the overlying small bowel loops.
Re-evaluation of the peritoneal space is indicated in patients
that fail to recover from trauma in an expected manner, since
it is possible that bleeding in the peritoneal cavity cannot be
identified until hours after the trauma, when the patient’s
blood volume has been restored and the blood pressure has re-
turned to normal. Peritonitis may also not be evident on ear-
ly radiographs.
3

Table 3.3: Radiographic features of peritoneal fluid
(Cases 2.14, 3.5, 3.8, 3.10, 3.11, 3.15, 3.17, 3.21, 3.22, 3.24, 3.29 & 3.30)
1. Loss of contrast between abdominal organs
2. Failure to identify
a. liver margin
b. spleen
c. urinary bladder
d. serosal surface of bowel
e. abdominal wall
3. Bowel loops in a patient with peritoneal effusion
a. appear to float
b. are widely separated
4. Increase in tissue density within the peritoneal space
5. Distended abdomen
3.1.4.4 Peritoneal air
The presence of peritoneal air may follow the perforation or
rupture of a hollow viscus, rupture of the urinary bladder, or
a perforating wound through the abdominal wall. Peritoneal
air tends to remain in small pockets and is difficult to identify
radiographically, because it lies within the mesenteric and
omental folds. Also the air bubbles are distributed over a large
portion of the abdomen and are not seen in one pocket, be-
cause most abdominal radiographs are made with the patient
recumbent (Table 3.4).
If a large amount of air is present, diagnosis is easier. The air
tends to accumulate around the liver if the radiograph is made
with the patient in lateral positioning. Both sides of the di-
aphragm are visible due to the pulmonary air cranially and the
free peritoneal air caudally. On the DV view, the air can gath-
er around the kidneys and make them more easily visualized.
This can be difficult to understand since the air is peritoneal
and the kidneys are retroperitoneal; however, the kidneys are
freely movable so that peritoneal air contrasts sharply with
their margins. An important radiographic sign is the sharp
identification of both the serosal and mucosal surfaces of a
bowel wall indicating that peritoneal air is present.
The easiest method of confirming suspected peritoneal air is
to make a radiographic study using a horizontal x-ray beam.
By positioning the patient on the x-ray table in lateral recum-
bency for 10–15 minutes prior to making the exposure, the air
collects in the uppermost portion of the abdominal cavity and
creates a pocket that can be more easily identified beneath the
abdominal wall. Using the left lateral positioning of the patient
permits the gas to collect between the right diaphragmatic crus
and the liver. It can be more readily identified in this location
because the peritoneal air is away from, and so not confused
with, the air in the fundus of the stomach. While this tech-
nique has a high percentage of accuracy in the detection of the
free air, it is not commonly performed because of the time and
effort to achieve it.
Abdominal air can be present for a period of several days to
several weeks following laparotomy, abdominal paracentesis,
or the use of pneumoperitoneography as a diagnostic tech-
nique and can be mistaken for air associated with a traumatic
event. An accurate clinical history is important in such cases.
Table 3.4: Radiographic features of peritoneal air
(Cases 3.9, 3.10 & 3.15)
1. Air pockets can be identified
a. between liver and diaphragm
b. adjacent to kidneys
c. between stomach and diaphragm or around stomach
2. Air creates triangular or circular-shaped pockets if located between
bowel loops
3. Bowel wall thickness is identified because of the air in the bowel lumen
and the air in the peritoneal cavity.This means that the air contrasts
with both serosal and mucosal surfaces of the bowel wall.
3.1.4.5 Retroperitoneal fluid
If fluid comes from an injured kidney or ureter and is blood or
urine, it often remains retroperitoneal and can be identified
radiographically by a large fluid-dense mass lying in a periver-
tebral location that effects the position of the adjacent organs
(Table 3.5). The renal shadows can remain visible because they
hang ventrally into the peritoneal space. A caudodorsal accu-
mulation of fluid may create a mass-like effect and result in the
ventral displacement of the descending colon and rectum.
Vertebral fractures can be associated with injuries causing the
presence of retroperitoneal fluid. It is also possible for fluid to
accumulate in the retroperitoneal spaces within the pelvic
cavity due to hemorrhage secondary to a pelvic fracture.
Table 3.5: Radiographic features of retroperitoneal fluid
(Cases 2.50, 3.18, 3.21 & 3.23)
1. Retroperitoneal space
a. increase in size
b. increase in fluid density
c. disappearance of radiolucent perivertebral fat shadows
d. non-visualization of sublumbar muscles (quadratus lumborum,
psoas major, psoas minor)
2. Kidneys
a. displaced ventrally
b. incomplete visualization
c. asymmetry of renal size
3. Descending colon and rectum are displaced ventrally
4. Associated fractures
a. vertebral
b. pelvic
Radiographic features in abdominal trauma 201
3

3.1.4.6 Retroperitoneal air
Retroperitoneal air is uncommon and is more often second-
ary to pneumomediastinum, with the air passing from that re-
gion into the retroperitoneal space. Another possibility is a
tearing of the peritoneum and passage of air from the peri-
toneal space into the retroperitoneal space. Trauma to the
pelvic region can also permit air to move into the retroperi-
toneal space. A final possibility is a puncture wound into the
retroperitoneal space with the presence of a gas-producing
microorganism. The radiographic features for this condition
involve an increase in contrast created by the air as well as a
possible mass effect with abnormal positioning of the adjacent
organs (Table 3.6).
Table 3.6: Radiographic features of retroperitoneal air
(Cases 3.9 & 3.17)
1. Increased visualization of the
a. sublumbar muscles (quadratus lumborum, psoas major, psoas minor)
b. kidneys
2. Ventral displacement of
a. kidneys
b. small bowel
c. descending colon and rectum
3. Secondary to
a. pneumomediastinum
b. peritoneal air
c. subcutaneous emphysema or infection
d. pelvic canal air
3.1.4.7 Organ enlargement
Enlargement of solid parenchymatous abdominal organs in
cases of trauma can be due to subcapsular or encapsulated
hemorrhage following hepatic, splenic, or renal injury. En-
larged renal shadows can also be due to hydronephrosis fol-
lowing ureteral rupture. Since the fluid is contained beneath
the capsule, the border of the organ remains visible on the ra-
diograph, but the organ can appear larger, or with a different
shape or contour than usual. This radiographic feature is not
commonly seen.
3.1.4.8 The pelvis
In the event of generalized trauma, pelvic radiographs are rel-
atively easy to perform and permit the evaluation of the soft
tissues containing the distal colon and rectum, plus the termi-
nal ureters, urinary bladder, and urethra in addition to the
caudal lumbar vertebra, lumbosacral junction, sacrum, caudal
vertebrae, sacroiliac joints, pelvis, hip joints, and the proximal
femurs. Any of these structures can be traumatized and require
treatment. Often a combination of injuries effecting both the
soft tissues and bone or joint is present (See also Chap. 4.2.16
Pelvis).
3.1.5 Use of contrast studies in the
traumatized abdomen
3.1.5.1 Urinary tract trauma
Traumatic lesions of the urinary tract are frequent and excre-
tory urography (Table 3.7) and retrograde urethrocystography
(Table 3.8) can be helpful diagnostically. Excretory urography
is the most easily performed technique, since the trauma pa-
tient probably has a venous catheter in place because of a re-
quirement for fluid therapy. Therefore, it is convenient to in-
ject a positive contrast urographic agent at a rate of 1 to 2
ml/kg bw. Radiographs made at 5 to 10 minutes after the in-
jection will show the bilateral function of normal kidneys. Fol-
lowing trauma, one or both kidneys can fail to excrete the
contrast agent because of renal artery thrombosis, renal artery
tear, avulsion of the kidney, or kidney injury. The contrast
agent can accumulate within the renal subcapsular space indi-
cating renal laceration. If the contrast agent leaks into the
retroperitoneal space this indicates renal laceration or ureteral
tear. The contrast agent can also leak into the peritoneal space
if the peritoneum is torn subsequent to any of these injuries.
Sequential radiographs will show the character of the ureters,
the position of the urinary bladder, and the status of the blad-
der wall.
If it is possible to catheterize the urinary bladder in a retro-
grade direction, the location of the bladder, the status of the
bladder wall, and the status of the urethra can be determined.
The urethra is evaluated following repositioning of the
catheter tip so that it lies within the distal urethra.
Table 3.7: Radiographic features of excretory urography in trauma
patients
(Cases 3.18, 3.20, 3.23, 3.24, 3.27, 3.29 & 3.32)
1. Failure of normal renal opacification/excretion by contrast agent because
of a
a. torn renal artery
b. torsion of the renal artery
c. thrombosis of a renal artery
2. Extravasation of contrast medium into the
a. subcapsular space because of renal laceration
c. peritoneal space because of renal laceration and capsular tear
d. retroperitoneal space because of renal laceration and capsular tear
e. retroperitoneal space because of ureteral tear
3. Hydronephrosis because of ureteral injury
4. Hydroureter because of ureteral injury
5. Failure of normal visualization of urinary bladder because of
a. renal or ureteral injury that fails to funnel contrast agent into bladder
b. incomplete filling of bladder because of tear in the bladder wall
6. Peritoneal extravasation of contrast agent because of bladder wall tear
7. Extravasation of contrast agent into the pelvic spaces because of
a. bladder neck injury
b. proximal urethral injury
3

Table 3.8: Radiographic features of retrograde urethrography/
cystography in trauma patients
(Cases 3.12, 3.19, 3.20, 3.21, 3.22, 3.25, 3.26, 3.27, 3.28, 3.29 & 3.30)
1. Extravasation of contrast medium into the
a. peritoneal space because of bladder wall injury
b. peritoneal space because of proximal urethral injury
c. pelvic space because of
I. proximal urethral injury
II. bladder neck injury
d. peri-urethral space because of urethral injury
2. Contrast column may indicate an abnormal mucosal surface due to
a. injury
b. stricture
c. tear
3. Malposition of the
a. urinary bladder
b. urethra
4. Foreign body (catheter)
3.1.5.2 Gastrointestinal tract trauma
Traumatic lesions of the intestinal tract are frequent and are
generally identified by evaluation of noncontrast radiographs
and the identification of peritoneal fluid or air. In patients
with a rupture of the wall of the stomach or bowel, it is pos-
sible that the tear is large enough to permit the release of in-
gesta or the barium contrast agent into the peritoneal cavity;
however, this is an uncommon finding. Often the most im-
portant radiographic finding is simply a determination of the
location of the hollow viscus. Displacement of a part of the
gastrointestinal tract is common in hernias and this is readily
determined by identifying the positive contrast within the dis-
placed stomach or small bowel (Table 3.9).
When used, these contrast studies involve the oral administra-
tion of barium sulfate suspension according to the following
schedule: 8–10 ml/kg bw in small dogs that weigh less than
10 kg, 5–8 ml/kg bw in medium-sized dogs that weigh be-
tween 10–40 kg, and 3–5 ml/kg bw in large dogs that weigh
more than 40 kg; and 12–16 ml/kg bw in the cat. These
dosages are necessary to insure a meal volume that will induce
normal peristalsis. Often, however, the study is made only to
evaluate the location of an organ and the amount of barium
sulfate meal administered can be less. Radiographs are then
made shortly after the administration of the meal, but they can
also be made at varying time intervals following administration
of the contrast agent depending on the information to be
gained. In trauma patients, these studies are rarely functional
in nature, but are only made to identify the location of the or-
gan and the integrity of its walls.
Table 3.9: Radiographic features of gastrointestinal trauma
following orally administered contrast agent
(Cases 3.3–3.9)
1. Displacement of
a. gastro-esophageal junction
b. stomach
c. small bowel
2. Distention of
a. stomach
b. small bowel
3. Extravasation of contrast agent into
a. peritoneal space
4. Failure of transit of contrast agent
Gastric foreign bodies
Gastric foreign bodies are noted frequently on the radiograph-
ic studies. Their identification is dependent on their density
(Table 3.10), and if surrounding gastric air provides contrast or
if ingesta hides the object. If the foreign bodies are obstructive,
the clinical importance is greater. Most are only impressive be-
cause of their radiographic appearance that is often influenced
by the patient positioning.
Table 3.10: Radiographic density of common gastric foreign bodies
(Cases 3.1, 3.2, 3.5, 3.6, 3.7 & 3.8)
1. Greatest density
a. glass with high lead content
b. metallic objects
c. heavy plastic objects
d. gravel and rocks
e. large bony fragments
2. Medium density
a. aluminum sheets or strips
b. glass with low lead content
c. plastic toys
d. ornaments
e. small bone fragments
3. Lowest density
a. ingesta
b. cloth strips or cloth toys
c. plastic sheets orbags
d. paper
e. string or rope
왘
Use of contrast studies in the traumatized abdomen 203
3

3.2.1 Gastric foreign bodies and
dilatation
Case 3.1
Signalment/History: “Frosty”, a 14-month-old, female
DSH cat, was presented because of intermittent vomiting over
the previous 1 to 2 months. Vomiting occurred every two to
three days and contained bile-stained fluid without food. The
use of lamb and turkey diets was unsuccessful in correcting the
clinical signs. No radiographic studies had been made.
Radiographic procedure: Abdominal studies were made
assuming a possible gastric foreign body.
Radiographic diagnosis: A 2-cm-in-diameter, discoid ob-
ject with a metallic density and a slightly irregular border lay
within the region of the pylorus. The small bowel loops were
filled with fluid, but not distended. The colon was gas-filled.
No radiographic signs of an obstructive ileus were noted.
Treatment/Management: A partially dissolved copper pen-
ny was removed by gastroscopic technique. The pyloric
antrum was noted to be highly inflamed. The chronic gastri-
tis resulting from the foreign body was thought to be the cause
of the vomiting. “Frosty” improved clinically following re-
moval of the foreign body.
3

Case 3.2
Signalment/History: “Chris” was a 6-year-old, female
German Shepherd with a history of depression, vomiting, and
hematuria over the previous two days.
Physical examination: The abdomen was tender on physi-
cal examination.
Radiographic procedure: The abdomen was radiographed.
Radiographic diagnosis: Radiopaque gastric foreign bodies
could be seen with a tissue density suggesting either a metal-
lic, glass-like, or dense plastic composition.
Note the difference in radiographic density of the foreign
bodies according to the patient’s position. The lack of contrast
between the abdominal organs suggested the presence of peri-
toneal fluid.
Treatment/Management: “Chris” died from chronic
pyelonephritis that had resulted in hypertension, myocardial
vascular damage, uremia, widespread mineralization, and
parathyroid hyperplasia.
The gastric foreign bodies were glass, but were not thought to
have contributed to the production of the clinical signs. Dogs
often eat a variety of debris along with their usual diet or
sometimes find these objects in a convenient garbage can. In
either situation, the resulting radiographic shadows are promi-
nent and may suggest clinical importance. The debris may be
obstructive or may be injurious to the mucosal surface; how-
ever, if small, they usually pass through the gastrointestinal
tract and do not cause more than acute, short-lived clinical
problems.
Gastric foreign bodies and dilatation 205
3

Case 3.3
Signalment/History: “Bingo” was a 1-year-old, dachshund
mixed breed with a history of gagging and choking after eat-
ing.
Physical examination: The abdomen was distended on pal-
pation, but was not noticeably painful.
made.
Radiographic diagnosis: The stomach was distended and
filled with ingesta. No evidence of a “pillar” sign or “shelf
sign” was present that could have suggested a gastric volvu-
lus/torsion. The pylorus was on the right side in its normal po-
sition. The colon was filled with feces that had the same ap-
pearance as the gastric contents. The small bowel loops were
air filled but not distended.
Treatment/Management: The patient was treated as hav-
ing marked gastric distention and was given a cleansing ene-
ma.
3

Radiographic diagnosis: Radiographs made after the ene-
ma showed the stomach to have emptied. Small bowel loops
could not be identified. The colon had refilled after the ene-
ma.
Treatment/Management: “Bingo” was thought to have
had overeaten and returned to normal after the enema.
Gastric foreign bodies and dilatation 207
3

3.2.2 Small bowel foreign bodies
Case 3.4
Signalment/History: “Pepper” was an 8-year-old, female
Terrier mix with a history of vomiting for several days.
Physical examination: Palpation of the abdomen revealed a
hard mass in the caudal abdomen the size of a “nut”.
abdomen.
Radiographic diagnosis (day 1): The stomach was dis-
tended and filled with air and fluid. The small bowel loops
were filled with fluid, although they had a normal diameter.
A 2-cm-in-diameter foreign body was located in the midpor-
tion of the caudal abdomen. It had a “slit-like” lucency in the
center, in addition to a “ring shaped” lucency around its edge.
3
Day 1

Radiographic diagnosis (day 2): Studies made one day lat-
er again showed a distension of the fluid-filled stomach. The
foreign body had the same appearance and was in the same lo-
cation. A sentinel loop of distended fluid-filled bowel was dia-
gnostic of being secondary to an obstructing foreign body (ar-
rows).
Treatment/Management: The nut was removed from the
bowel surgically and “Pepper” recovered quickly. In some so-
cieties, it is possible to determine the season of the year and
holidays by the character of the foreign bodies found in the
bowels of pets.
Small bowel foreign bodies 209
3
Day 2

Case 3.5
Signalment/History: “Jenny” was a 1-year-old, female
DSH cat who was vomiting. She had been anorectic for sev-
eral weeks.
Physical examination: A cranial abdominal mass was evi-
dent on palpation.
made, followed by a compression study to further clarify the
nature of the suspect mass. Following failure of that procedure
to insure a specific diagnosis, a barium sulfate meal was used
to further identify the nature of the mass.
Radiographic diagnosis (noncontrast): A poorly mar-
ginated mass with a granular consistency was located in the left
cranial abdomen, immediately caudal to the liver. Loss of mu-
cosal borders suggested the possibility of focal peritoneal flu-
id. Both the stomach and small bowel loops were empty. A
proximal partially obstructing intestinal lesion was suspected.
The use of a compression device separated the questionable
mass from the liver and stomach indicating that it was proba-
bly intestinal and was not associated with a focal peritoneal ef-
fusion.
3
Noncontrast

Radiographic diagnosis (barium sulfate meal): Radio-
graphs made 20 minutes after the administration of a contrast
meal showed a lesion in the descending duodenum that was
characterized by a marked distention of the bowel with the
contrast agent mixing with an intraluminal mass. A portion of
the liquid meal passed the lesion and was seen within the dis-
tal bowel loops. The contrast study confirmed the presence of
a partially obstructing luminal mass within the descending
duodenum.
Treatment/Management: A mass of thick paper was re-
moved at surgery and “Jenny” was discharged a happy cat.
Comments: Intraluminal foreign bodies tend to distend the
bowel lumen and prevent the contrast meal from outlining a
smooth mucosal surface. If some of the meal passes the foreign
body, the distal bowel loops will be partially filled. A differ-
ential diagnosis radiographically should include an intestinal
tumor.
3
Barium sulfate meal

Case 3.6
Signalment/History: “Grace” was a 10-month-old, female
DSH cat with a history of vomiting for a period of seven days.
abdomen because the length of the clinical history suggested
an obstructive type lesion.
Radiographic diagnosis: A mid-abdominal metallic foreign
body was associated with enlarged, fluid-filled small bowel
loops. The lack of visualization of definite serosal margins sug-
gested the possibility of an associated peritonitis.
Treatment/Management: Surgical removal of the metallic
“can-opener” required a bowel resection. Unfortunately
“Grace” had a complicated recovery and died in the clinic
twelve days after surgery. Necropsy located a small bowel ab-
scess at the site where the intestinal anastomosis was per-
formed.
3

Case 3.7
Signalment/History: “Shannon”, a 1-year-old, female
Siamese cat, had a history of having swallowed thread a week
earlier. On presentation, she was vomiting and had been
anorectic for the previous five days.
Physical examination: The abdomen was painful on palpa-
tion and multiple bowel loops felt thickened, suggesting a lin-
ear foreign body.
Radiographic procedure: Studies of the abdomen were
made.
Radiographic diagnosis: The small bowel loops were
thickened, clumped together on the right side of the abdomen
and contained small pockets of air (arrows). A radiographic
pattern of this type would be expected in a patient with a small
bowel linear foreign body causing a partial obstruction.
Treatment/Management: What was initially a partial small
bowel obstruction became complete after the inflammatory
changes caused by the linear foreign body cutting through the
bowel wall resulted in an adhesive mass. The surgical treat-
ment involved bowel resection, but was not successful.
Comments: Because the bowel wall essentially heals itself as
the string “cuts” through it, the peritonitis in such cases re-
mains focal in location and a widespread inflammatory process
in the peritoneal cavity is not typically a part of this syndrome.
3

Case 3.8
Signalment/History: “Chamois” was a 2-year-old, female
Labrador Retriever with a four-day history of vomiting. Diar-
rhea was noted during the previous 24 hours.
Physical examination: Dilated small bowel loops were pal-
pated.
Radiographic procedure: Abdominal studies were made.
Radiographic diagnosis: A single distended gas-filled small
bowel loop was visible indicative of obstructive bowel disease
(arrows). Note that the gastrointestinal tract both cranial and
caudal to the site of obstruction was empty. Separation of the
distended small bowel from the larger colon was difficult;
however, the appearance of the bowel walls made identifica-
tion of the loops possible. The small bowel wall was smooth,
while the colonic wall had a typical corrugated appearance.
Also, the small bowel loop was dorsal to the colon and far to
the right. In comparison, the colon was far to the left on the
DV view in a more normal location.
Note on both views the fluid dense mass within the lumen of
the distended loop that represents the foreign body.
Comments: A single loop (“sentinel loop”) syndrome is typ-
ical of an early complete bowel obstruction that is often the re-
sult of an intraluminal mass (foreign body); however, a bowel
wall tumor can cause a similar pattern radiographically, if it
should quickly develop into an obstructive lesion.
3

3.2.3 Peritoneal fluid
Case 3.9
Signalment/History: “Bonnie”, a 2-year-old, female Great
Dane, had a bullet wound in her left flank.
tion.
abdomen searching for the bullet tract.
Radiographic diagnosis: The metallic bullet lay within the
retroperitoneal space on the midline just ventral to L6–7. The
abdomen had lost contrast probably due to accumulation of
peritoneal fluid. The pattern of gas within the abdomen did
not follow that seen normally with bowel gas and free peri-
toneal air was suspected. The retroperitoneal space had lucent
linear shadows suggesting free air in this location also. One air-
filled bowel loop was greatly distended suggesting the possi-
bility of an ileus.
Treatment/Management: The metallic fragment was typi-
cal for a rifle bullet that has struck only soft tissue and as a con-
sequence was only slightly malformed. An abdomen with the
appearance of free fluid and air strongly suggests the likelihood
of a ruptured bowel.
“Bonnie” was returned to the referring clinician for surgery
and was lost to follow-up.
Peritoneal fluid 215
3

Case 3.10
Signalment/History: “Regulus”, a 10-month-old, male
DSH cat, was presented with a history of vomiting after being
absent from home for several days.
tion.
Radiographic procedure: Radiographic studies of the ab-
domen were made.
Radiographic diagnosis: A diffuse pattern of peritoneal
fluid was noted throughout the abdomen, but principally sur-
rounding the body of the stomach. Scattered pockets of air
were indicative of pneumoperitoneum. The air-filled, dis-
tended small bowel was indicative of a paralytic ileus. Note
how the bowel loops appear to “float” on the surface of the
peritoneal fluid. Feces remained within the distal colon.
3

A positional study using a horizontal beam was made with the
dog in right lateral recumbency. This permitted movement of
the peritoneal air to a pocket just caudal to the body of the
stomach (arrow).
Treatment/Management: A perforated jejunum was locat-
ed at surgery, which required a bowel resection. The cat was
discharged following a recovery period in the clinic. The spe-
cific cause of the perforation was not determined.
3

Case 3.11
Signalment/History: “Freya” was a 5-month-old, female
mixed-breed dog who had been hit by a car and was present-
ed in shock.
Physical examination: The examination was limited; how-
ever, palpation indicated that bones in the dog’s forelimb were
fractured. Pelvic fractures were suspected as well.
thorax. Following their evaluation, it was determined that ad-
ditional studies of the caudal abdomen/pelvis, and the right
forelimb could be made without risk to the patient.
Radiographic diagnosis (thorax): Lung contusion was
minimal, though it was more severe caudally on the left in as-
sociation with minimal pleural effusion. Fractures of the right
9th
(arrow), 11th
, 12th
, and 13th
ribs near the costovertebral
joint were difficult to diagnose. Both the cardiac silhouette
and the pulmonary vessels were smaller than expected, prob-
ably due to shock.
3

Radiographic diagnosis (caudal abdomen): Loss of con-
trast between the abdominal organs was due to peritoneal flu-
id. A sacral fracture, left sacroiliac fracture/luxation, and right
acetabular fracture were present. A distal femoral fracture on
the left was almost overlooked on the radiographic evaluation.
Radiographic diagnosis (right forelimb): Transverse
fractures of the right radius and ulna were noted on addition-
al studies.
Treatment/Management: The study of the abdomen was
limited to the pelvic region. The cause of the peritoneal fluid
and the severity of the shock were not evaluated. The dog died
four hours following the radiographic studies after an attempt
at controlling the intra-abdominal hemorrhage was unsuccess-
ful.
In this patient, the absence of extensive injury to the thorax
did not match the severity of the abdominal and skeletal in-
juries.
3

3.2.4 Inguinal hernias
Case 3.12
Signalment/History: “Blackie” was a 4-year-old, female
DSH cat who had been hit by a car eight days earlier and was
referred because the cat did not have the full use of its pelvic
limbs.
Physical examination: The pelvis palpated abnormally with
a suggestion of crepitus bilaterally. A full feeling in the in-
guinal region suggested a soft tissue injury.
made followed by a retrograde urethrogram.
Radiographic diagnosis (abdomen): Small bowel loops
filled with air extended across the abdominal wall into the in-
guinal region indicating an inguinal hernia. The abdominal
wall could not be identified on the right on the DV view. The
air-filled bowel loops extended laterally far beyond the limits
of the abdominal cavity. The urinary bladder could not be
identified. The bilateral sacroiliac luxations were noted with a
cranial displacement of the pelvis.
3

Radiographic diagnosis (retrograde urogram): The
contrast medium leaked into the peritoneal cavity indicating a
tear in the urethra or bladder wall. The tip of the catheter had
been placed in the bladder limiting the information relative to
the urethral injury.
The hip joints could be studied more clearly on the VD view
and showed bilateral arthrosis, probably secondary to hip dys-
plasia.
Treatment/Management: At surgery, a rupture in the vagi-
nal wall was repaired in addition to an urethral tear and the in-
guinal hernia.
Inguinal hernias 221
3
Retrograde urogram

Signalment/History: “Tai Chi” was a 5-year-old, male
Pekingese, who had been absent from home for several days.
Upon return, the owners noted he was vomiting and then be-
came anorectic. No stool had been passed.
Physical examination: Scrotal swelling was evident on
physical examination with the exact nature of the scrotal con-
tents not determined.
Radiographic procedure:Caudal radiographs were made in
an effort to more fully evaluate the nature of a suspected her-
nia.
Radiographic diagnosis: Multiple, small, well-circum-
scribed inguinal gas shadows were thought to be small bowel
gas patterns, in which case an inguinal hernia was present
(arrows). The pelvis was difficult to evaluate properly because
of patient positioning.
Treatment/Management: Exploration of the suspected in-
guinal hernia revealed an incarcerated distal jejunum that re-
quired an intestinal anastomosis. An infarcted right testicle was
removed surgically.
Case 3.13
Comments: Herniated bowel loops cannot be considered a
trivial lesion. Less likely etiologies for such an inguinal gas col-
lection include the presence of a gas-producing organism caus-
ing an infectious lesion or a break in the skin permitting the
entrance of subcutaneous air.
3

Case 3.14
Signalment/History: “Toot” was a 5-year-old, male DSH
cat that was presented to the clinic following suspected trau-
ma.
Physical examination: An inguinal hernia containing easily
palpated bowel loops was found. Identification of the urinary
bladder was questionable.
Radiographic procedure: Routine studies of the abdomen
failed to identify the location or status of the urinary bladder,
so a retrograde contrast study was performed.
Radiographic diagnosis (abdomen): The left-sided in-
guinal hernia contained multiple gas-filled, small bowel loops.
The luminal diameter of the bowel loops was thought to be
within normal limits (<11cm) and did not suggest bowel ob-
struction. The urinary bladder could not be identified on the
noncontrast study. Left femoral head and neck fractures were
seen.
3

Radiographic diagnosis (retrograde cystogram): This
showed the displaced and ruptured urinary bladder lying
within the hernial sac. The bladder was partially filled and lay
just ventral to the abdominal wall. The majority of the con-
trast agent spilled into the hernial sac.
Treatment/Management: Treatment was not permitted
and the cat was euthanized.
3
Retrograde cystogram

Case 3.15
Signalment/History: “Canoe”, a 3-year-old, male mixed-
breed dog, had received crushing injuries from an automobile
accident and was presented in shock.
Physical examination: The examination was severely limit-
ed by the condition of the patient.
Radiographic procedure: Thoracic and abdominal radi-
ographs were made.
Radiographic diagnosis (thorax): Generalized lung con-
tusion was more severe on the right side. Fluid pooling adja-
cent to the sternum just cranial to the heart shadow suggested
a minimal pleural effusion. Minimal pneumothorax was pres-
ent on the left. Cranial mediastinal widening suggested the
possibility of a hemomediastinum. The pulmonary vessels
were small, indicative of shock. The diaphragm appeared to be
intact. No thoracic wall injury was noted. The stomach was
air-filled and distended, the result of panic breathing.
3

Radiographic diagnosis (abdomen): Subcutaneous em-
physema was associated with a right-sided inguinal hernia that
contained intestinal loops. The urinary bladder could not be
identified. Pneumoperitoneum was suggested by the indistinct
linear gas patterns that were not compatible with the air with-
in the bowel loops. The loss of contrast between the organs
suggested peritoneal fluid. The diaphragm had remained in-
tact.
Radiographic diagnosis (abdomen, horizontal beam):
Free peritoneal air was pocketed just beneath the diaphragm
making it rather easy to identify (arrows).
Treatment/Management: The injuries were extensive and
severe; however, “Canoe” was treated conservatively except
for a surgical repair of the inguinal hernia. He was discharged
a healthy dog.
3

Case 3.16
3

Signalment/History: “Rufus” was a 6-month-old, male
mixed-breed cat admitted because he could not walk on the
right pelvic limb. The lameness had had an acute onset.
Physical examination: Examination suggested a right
femoral fracture. Additional crepitus was noted on palpation
of the pelvis. The status of the hip joints was not determined.
Soft tissue swelling was prominent especially around the right
pelvic limb.
Radiographic diagnosis: A comminuted, midshaft, right
femoral fracture was complicated by an apparent right inguinal
hernia with bowel loops extending subcutaneously and distal-
ly into the pelvic limb. The bowel loops were thought to be
excessive in diameter and were considered obstructed. Pubic
and ischial fractures had resulted in separation of the two halves
of the pelvis. The right femoral neck was fractured; however,
the exact nature of that fracture could not be determined be-
cause of the unique positioning of the pelvic limb. The right
sacroiliac joint was separated. The urinary bladder could not
be identified.
Treatment/Management: Surgery resulted in a reduction
of the obstructed bowel loop and stabilization of the femoral
fracture. A femoral head ostectomy was used to treat the
femoral head/neck fracture. The urinary bladder was found to
be uninjured.
3

3.2.5 Renal, ureteral, and urinary
bladder injury
Case 3.17
Signalment/History: “Amber” was a 6-year-old, female
mixed-breed dog with a clinical history of possible trauma.
She was not able to walk normally.
Physical examination: On physical examination, a femoral
fracture was detected. Abrasions of the skin suggested the pos-
sibility of more widespread injury.
Radiographic procedure: Both the thorax and abdomen
were radiographed because the injury appeared to involve the
whole body.
Radiographic diagnosis (abdomen): Marked subcuta-
neous emphysema was noted surrounding the injured pelvic
limb. In addition, retroperitoneal air was evident ventral to
the lumbar spine (arrows). The urinary bladder could not be
identified and the presence of peritoneal fluid supported the
diagnosis of a rupture of the bladder. Bilateral sacroiliac sepa-
ration was present.
3

Radiographic diagnosis (thorax): The thorax was exam-
ined for evidence of a pneumomediastinum, which could have
resulted in air migrating from the thorax into the retroperi-
toneal space. The thorax appeared normal except for having a
small cardiac silhouette and small pulmonary vessels both sug-
gesting shock.
Treatment/Management: The femoral fracture was open
and the retroperitoneal air may have gained entrance in that
manner. A rupture at the bladder neck or proximal urethra
could also have resulted in retroperitoneal air. Both of these
causes for retroperitoneal air are considered uncommon, but
as there was no evidence of pneumomediastinum in this dog,
they were taken into consideration. No evidence of a punc-
ture wound in the dorsal abdomen was found that could have
resulted in abdominal air.
“Amber” recovered from surgery for the repair of the rup-
tured bladder and the fractured femur.
Renal, ureteral, and urinary bladder injury 231
3

Signalment/History: “Lady”, a 9-month-old, female Col-
lie, had been hit by a truck 24 hours previously. She was in an
emergency clinic being treated for shock. The BUN level and
the WBC count were elevated.
Physical examination: Crepitus was detected in the pelvis.
The dog had not been observed to urinate since the accident
and the bladder could not be identified by palpation.
Radiographic procedure: Only lateral radiographs were
made of the abdomen and pelvis because of the severity of the
injuries.
Radiographic diagnosis: Marked gaseous distention of
small bowel loops in the midabdominal region suggested a
paralytic ileus. Loss of contrast between the abdominal viscera,
failure to clearly identify the urinary bladder, and failure to
identify the ventral abdominal wall all indicated free peri-
toneal fluid. Small air pockets throughout the abdomen sug-
gested the presence of free peritoneal air, too. Retroperitoneal
fluid indicated possible hemorrhage. An indistinct fluid-den-
sity inguinal mass was also thought to be probably due to free
hemorrhage.
Case 3.18
Treatment/Management: The small cardiac silhouette and
small pulmonary vessels were noted radiographically to in-
crease in size following administration of IV fluids. During
this time, the urinary bladder was noted to remain constant in
size suggesting that urine was leaking from the bladder. It was
decided that an excretory urogram was necessary.
Radiographic diagnosis (10 minutes following intra-
venous injection): Leakage of radiopaque contrast medium
in both the peritoneal and retroperitoneal spaces was sugges-
tive of a ruptured bladder neck and/or a torn ureterovesical
junction (arrows).
Treatment/Management: The paralytic ileus could have
been the result of the trauma indicating injury to the vascular
supply, mesenteric torsion, or herniation through a mesenteric
tear. In addition, it could have been the response to urine
within the peritoneal cavity. The dog was euthanized and the
body taken home without any further examination.
3
Noncontrast

3
Excretory
urogram

Case 3.19
Signalment/History: An adult male cat had been found by
the road unable to move and was brought to the clinic.
Physical examination: The patient was dyspneic and an in-
guinal hernia was palpated.
Radiographic procedure: Thoracic and abdominal studies
were made.
Radiographic diagnosis (thorax): A massive pneumotho-
rax had caused the collapse of the right lobes and a mediastinal
shift to the left. Pulmonary contusion had induced an increase
in fluid density in the left lung. An injury to the right thoracic
wall had fractured a number of ribs. Minimal subcutaneous
emphysema was present. The diaphragm appeared intact.
Radiographic diagnosis (abdomen): The urinary bladder
appeared within an inguinal hernia on the left, which also
contained air-filled small bowel loops. A right-sided pelvic
fracture included injury to the floor of the pelvis, but did not
affect the hip joint. Stress aerophagia resulted in the stomach
being distended with air.
3

Radiographic diagnosis (retrograde cystogram): The
retrograde study showed the catheter tip lying within the ure-
thra and a flow of contrast agent into the peritoneal cavity and
into the hernial sac. This extra-vesicular flow of the contrast
agent and the failure to fill the bladder with the agent sug-
gested a rupture of the urethra or bladder neck. The bladder
was thought to be within the hernial sac.
Treatment/Management: The cat was euthanized and the
necropsy confirmed the radiographic findings of a bladder
neck tear.
3

Case 3.20
Signalment/History: “King” was an 8-year-old, male Col-
lie with a suddenly appearing caudal mass. The owners sus-
pected that the dog had been struck by a car several weeks ear-
lier.
Physical examination:The mass was soft and fluid-filled, but
not painful on palpation. Both hip joints had limited motion.
Radiographic procedure: Both views were made of the ab-
domen and of the pelvis. In addition, both intravenous uro-
graphy and retrograde cystography were performed.
Radiographic diagnosis (noncontrast): A poorly mar-
ginated, soft tissue mass of uniform fluid density lay ventral to
the tail causing the gas-filled rectum to be displaced dorsally
(arrows).
Malunion pelvic fractures had caused a marked stenosis of the
pelvic canal. The hip joints were difficult to evaluate.
A healed caudal sacral fracture had induced a dorsal displace-
ment of the distal fragment.
Radiographic diagnosis (intravenous urography/retro-
grade cystography): A bilateral hydronephrosis and hy-
droureter was more prominent on the left on the ten-minute
study. The trauma had caused a displacement of the urinary
bladder and prostate gland into the perineal hernia. A urethral
catheter positioned into the urinary bladder could be identi-
fied on the study.
3
Noncontrast

Bilateral retention of the contrast agent in the pelvis and
ureters following the intravenous injection was evident on the
10-minute study. On the 30-minute study, drainage had oc-
curred from the right kidney and ureter; however, retention of
contrast agent persisted on the left side (arrows).
Comments: It is interesting to speculate whether the
retroflexion of the bladder had occurred at the time of the
trauma that caused the pelvic fractures or was secondary to
chronic straining in the months following the fractures. The
owners were correct in that the dog had been traumatized;
however, the trauma probably had been several months previ-
ously and not weeks as they had thought.
In the evaluation of the pelvic trauma, the status of the femoral
heads is important since their injury causes a major complica-
tion to treatment and healing, as well as the ultimate progno-
sis. In this patient, the femoral heads and necks appear not to
be traumatized. In comparison, the collapse of the pelvic inlet
is important clinically.
It was possible to correct the location of the abdominal organs
surgically, but little could be done concerning the malunion
fractures or injury to the acetabula.
3
Retrograde
cystography

Case 3.21
Signalment/History: A male DSH cat was found lying by
the side of the highway apparently having been struck by a car.
made, followed by a retrograde cystogram.
Radiographic diagnosis (abdomen): Small bowel loops
were “floating” within an abdomen without contrast and so
the latter was thought to contain peritoneal fluid. The urinary
bladder could not be identified.
3

Radiographic diagnosis (retrograde cystogram): The
positive contrast agent partially filled the urinary bladder;
however, a large portion of the contrast agent spilled into the
retroperitoneal cavity, peritoneal cavity, and extended into
the pelvic cavity.
Outcome: At necropsy, a 1–2 cm tear was located just cra-
nial to the trigone region of the urinary bladder. A tear in this
location had permitted urine to escape into all of the adjacent
body cavities. Splenic rupture with hemoperitoneum was also
noted.
3

Case 3.22
Signalment/History: “Ollie” was a 2-year-old, male DSH
cat with clinical signs of urinary obstruction.
Physical examination: On palpation, the urinary bladder
was difficult to feel and the abdomen felt somewhat distend-
ed. During the examination, a catheter was passed into the
bladder, but only a small amount of sanguinous fluid could be
removed.
Radiographic procedure: Noncontrast studies were made
of the abdomen and were followed by a retrograde cystogram.
Radiographic diagnosis (noncontrast): A fluid density
mass was located in the caudal abdomen ventrally, but in a lo-
cation thought cranial to the expected location of the urinary
bladder. Bowel loops were air-filled and appear to “float” on
a “sea” of peritoneal fluid, possibly urine. Loss of peritoneal
contrast further supported the diagnosis of peritoneal fluid.
Free peritoneal air was difficult to identify, but a large air
dense shadow was noted in the midabdomen dorsally on the
lateral view, and on the left side of the abdomen on the VD
view.
3
Noncontrast

Radiographic diagnosis (retrograde cystogram): A
small amount of positive contrast agent was injected through
the catheter with the agent passing directly into the peritoneal
cavity ventrally and to the right. The shadow thought to be
the urinary bladder did not fill with any of the contrast agent.
Treatment/Management: The owner refused treatment.
At necropsy, the catheter was found to have passed through an
opening in the urethra located 3 mm from the bladder neck.
The tip of the catheter was 4 cm beyond the urethral rupture
into the peritoneal cavity at the time of injection. The ap-
pearance of the urethral tear suggested a chronic lesion possi-
bly following an earlier effort at catheter placement.
While the study confirmed an injury, placement of the
catheter tip within the urethra would have been more inform-
ative and would have demonstrated a lesion that could have
been more easily repaired than was originally thought.
3

Case 3.23
Signalment/History: “Frodo”, an 11-month-old, female
DSH cat, was presented with a painful attitude.
Physical examination: She was febrile and had abrasions on
the skin of the right pelvic limb. Palpation of the abdomen dis-
closed pain principally on the left. Trauma was suspected.
Radiographic procedure: Abdominal studies were made
and were followed by an intravenous urogram.
Radiographic diagnosis (noncontrast): The left kidney
was displaced laterally with an indistinct soft tissue shadow lo-
cated at the side of its shadow. On the lateral view, the sub-
lumbar musculature was not sharply contrasted against the
retroperitoneal fat, and fluid was suspected in that compart-
ment. These findings suggested retroperitoneal fluid, perhaps
urine, and an intravenous urogram was performed.
3
Noncontrast

Radiographic diagnosis (intravenous urogram): Studies
made at 30 minutes following injection of the contrast agent
demonstrated hydronephrosis in the left kidney with disten-
tion of the proximal portion of the left ureter and leakage of
urine containing the contrast agent into the retroperitoneal
space. The distal portion of the left ureter was filled with con-
trast agent. The study showed a normally functioning kidney
on the right side and filling of the urinary bladder with con-
trast agent.
Treatment/Management: An unsuccessful attempt at sur-
gical repair of the torn ureter was followed by a second oper-
ation in which the affected kidney and proximal ureter were
surgically removed. The filling defect in the proximal portion
of the urinary bladder was probably caused by a blood clot.
“Frodo” recovered and renewed his search for Sam and Gol-
lum.
3
Intravenous urogram

Case 3.24
Signalment/History: A male DSH cat was found lying near
the side of the highway after apparently being struck by a car.
Radiographic procedure: Whole body studies were made,
followed by an intravenous urogram.
Radiographic diagnosis (noncontrast): Small bowel loops
were seen to “float” within an abdomen thought to contain
peritoneal fluid. The urinary bladder could not be clearly
identified. Because of these findings, it was assumed that the
urinary bladder might be ruptured and an intravenous uro-
gram was performed.
3
Noncontrast

Radiographic diagnosis (intravenous urogram): Radio-
graphs were made at 10 minutes and filling of the renal pelves
was evident. At 20 minutes, the hold-up of contrast agent in
the renal pelves was abnormal and the filling of the proximal
ureters suggested ureteritis, which could have been post-trau-
matic. However, the major finding was the leakage of contrast
agent into the perirenal tissues on the left (arrows). A diagno-
sis of a ruptured kidney was made.
Treatment/Management: The rupture of the kidney was
followed clinically and the cat improved without surgical in-
tervention and was discharged after three weeks. Radiographs
made two years later showed the left kidney to be of normal
size, shape, and position.
Comments: Even despite its retroperitoneal position, renal
injury often causes tearing of the peritoneum and leakage of
urine or blood into the peritoneal space.
3
Intravenous urogram

3.2.6 Urethral injury
Case 3.25
Signalment/History: “Rogue”, a 2-year-old, male Bichon
Frise, was presented with a history of recurrent urinary calculi.
Physical examination: The urinary bladder was easily pal-
pable. Physical examination was limited because of the ques-
tionable status of the bladder and urethra.
Radiographic procedure: Routine studies were made of
the caudal abdomen, followed by retrograde urography.
Radiographic diagnosis (noncontrast): The noncontrast
studies showed a distended bladder with air bubbles probably
secondary to the removal of urine from the bladder. No cystic
or urethral calculi were noted. The absence of peritoneal con-
trast suggested the presence of peritoneal fluid.
Radiographic procedure (retrograde urography): The
catheter tip was positioned within the penile urethra and a ra-
diograph made following a small injection of positive contrast
agent. Subsequently, a larger injection was made.
The flow of contrast agent outlined a badly damaged urethral
mucosa at the urethral arch with extravasation of the contrast
agent into the periurethral tissues. The prostatic urethra was
dilated. A portion of the contrast agent flowed into the uri-
nary bladder, which appeared intact.
3
Noncontrast

Outcome: A necropsy examination followed unsuccessful
emergency surgery. The urethra was ruptured just distal to the
ischial arch and a calculus was located in the surrounding tis-
sues. A necrotic cystitis was evident. It was thought that the
calculus had been driven through the urethral wall by the pas-
sage of a urethral catheter at an earlier date.
Urethral injury 247
3
Retrograde urography

Case 3.26
Signalment/History: “Andy”, a 1-year-old, male DSH cat,
was presented for emergency treatment of a blocked urethra.
He had had dysuria for seven days and was thought to have not
urinated for at least 24 hours prior to presentation.
Physical examination: A large, firm bladder was palpated
and a local anesthetic was sprayed into the urethra. Immedi-
ately following this medication, the bladder could not be pal-
pated.
Radiographic procedure: Noncontrast studies of the ab-
domen were made and followed immediately by a retrograde
urethrocystogram.
Radiographic diagnosis (abdomen): Distention of the
small bowel was indicative of a paralytic ileus. The loss of ab-
dominal detail suggested the presence of peritoneal fluid while
the pattern of free peritoneal air indicated a pneumoperi-
toneum.
3
Noncontrast

Radiographic diagnosis (retrograde urethrocysto-
gram): The catheter tip was positioned in the urinary bladder
and partially filled that structure. Some of the urine-contain-
ing contrast agent was seen to have escaped from a tear in the
midportion of the urethra, while a part of the liquid had spread
into the retroperitoneal space dorsally.
A long-standing left femoral neck fracture could be seen with
resorption of the femoral head and the formation of a
pseudoarthrosis.
Comments: The location of the catheter tip during the ret-
rograde study determines your ability to demonstrate a prox-
imal urethral injury. In this patient, the urine flowed out of
the bladder into the urethra and demonstrated the urethral
tear. It might have been better to have positioned the catheter
tip first of all in the urethra to ensure identification of the ure-
thral tear and then move the catheter tip into the bladder to
determine the status of the bladder wall.
The complete disappearance of the left femoral head on this
study indicates an injury of several months duration.
Urethral injury 249
3
Retrograde urethrocystogram

Case 3.27
Signalment/History: “Simpson”
was a 4-year-old, male Dalmatian
with a chronic history of urethral
blockage, which had been treated
medically but had also required a
prepubic urethrostomy.
Radiographic procedure: Non-
contrast studies of the abdomen
were performed and were followed
by an intravenous urogram.
Radiographic diagnosis (ab-
domen): Areas of calcification were
noted in the region of the fundus of
the urinary bladder and also more
caudally in the region of the prostate
gland.
3
Noncontrast

Radiographic diagnosis (intra-
venous urogram): The intra-
venous study showed normal func-
tioning kidneys with persistent fill-
ing of tortuous ureters indicative of
ureteritis. Filling defects in the uri-
nary bladder suggested intraluminal
blood clots and/or radiolucent cal-
culi. Areas of calcification were
identified within the thickened
bladder wall and within the prostate
gland.
Radiographic diagnosis (retro-
grade urethrogram): Retrograde
studies were made following injec-
tion of the positive contrast agent
with the tip of the catheter at the
end of the penis. A retained catheter
from an earlier study extended into
the area of the prostatic urethra
(arrows). Marked mucosal distortion
at the end of the penis suggested
both intraluminal calculi as well as
mucosal stricture.
Treatment/Management: Re-
moval of the calculi and sand from
the bladder, plus removal of the re-
tained catheter were carried out sur-
gically.
Comments: Filling defects within
the urinary bladder in an older pa-
tient always require the inclusion of
bladder wall tumor in the differential
diagnosis. Dystrophic calcification
within the bladder or prostate gland
can be the result of chronic inflam-
matory disease or can be associated
with neoplasia.
Urethral injury 251
3
Intravenous urogram
Retrograde urogram

Case 3.28
3
Noncontrast
Retrograde urethrogram

Signalment/History: A 3-year-old, male Boxer was
brought to the clinic because the owner had noted blood in his
urine.
Physical examination: Examination indicated that what the
owner thought was a red coloration in the urine, was instead,
actually bleeding from the penis.
Radiographic procedure: Noncontrast studies were made
of the abdomen with a special view of the urethral region with
the pelvic limbs flexed. A retrograde urethrogram was then
performed.
Radiographic diagnosis (noncontrast): No evidence of
any calculi was seen on the noncontrast studies. The urinary
bladder was difficult to identify. No signs of peritoneal fluid
were evident as would be anticipated with a bladder rupture.
Radiographic diagnosis (retrograde urethrogram): The
retrograde study was performed with the catheter tip just
proximal to the penile urethra. Contrast agent was seen to fill
the urethra and enter the bladder in a normal fashion. Rather
unexpectedly, the contrast also entered the corpus cavernosum
of the penis and drained into the venous return (arrows).
Treatment/Management: Further information was ob-
tained from the owner that included a chronic history of dif-
ficult urination, which had required frequent catheterization.
It was assumed that repeated urethral trauma had caused injury
to the mucosa.
Comments: While the radiographs were rather remarkable,
of more importance was the potential stricture at the site of
the mucosal injury and the possibility of continued dysuria.
Urethral injury 253
3

Case 3.29
Signalment/History: “Pokey”
was a 2-year-old, male mixed-breed
dog who had been hit by a car.
Physical examination: Palpation
of the pelvic limb suggested a frac-
tured femur. The caudal abdominal
wall appeared to be torn or rup-
tured.
Radiographic procedure: A sin-
gle lateral view of the abdomen was
made to evaluate possible abdominal
injury as well as to obtain a single
view of the fracture. On day 2, a
retrograde urethrogram was per-
formed.
Radiographic diagnosis (day 1,
immediately post trauma): Fail-
ure to identify the abdominal wall
plus loss of abdominal contrast indi-
cated the presence of peritoneal flu-
id. Displacement of the bowel loops
from the caudal region suggested an
inguinal mass resulting from the
trauma. Peritoneal hemorrhage and/
or edema, and urinary bladder rup-
ture or herniation were all consid-
ered. The midshaft oblique femoral
fracture was noted along with frac-
tures of the floor of the pelvis.
3
Day 1
Day 2

Radiographic diagnosis (day 2, retrograde urethro-
gram): Extravasation of contrast agent into the pelvic exten-
sion of the retroperitoneal space and into the inguinal region
could be seen in the urethrogram. Contrast agent failed to en-
ter the urinary bladder probably due to a urethral rupture at
the bladder neck. Air bubbles made a specific pattern in the
urethra. Contrast agent had been spilled on the hair coat and
caused a peculiar pattern of radiographic artifact.
Treatment/Management: Surgery was performed without
further evaluation of the upper urinary system. The urethral
rupture and injury to the abdominal wall were both repaired.
Injury to the right ureter was noted, but not treated.
Radiographic diagnosis (day 4, intravenous urogram,
20-minute studies): Delayed emptying of the right kidney
was persistent on the later studies of the examination. The left
kidney and ureter appeared to function normally. A separation
of the right sacroiliac joint and public and ischial fractures were
noted.
Treatment/Management: “Pokey” had a hemolytic crisis
and died ten days after surgery. A stricture of the distal right
ureter was noted at necropsy and was incorporated in the ure-
thral scar causing delayed emptying.
Comments: In some trauma patients, it is appropriate to
evaluate both the upper and lower portions of the urinary sys-
tem before proceeding to surgery.
Urethral injury 255
3
Day 4

Case 3.30
Signalment/History: “Freedom” was a 1-year-old male
Siamese cat who had been traumatized in some manner and
was found outside of the house by his owner.
Physical examination: The cat was in severe shock.
Radiographic procedure: Both thoracic and abdominal ra-
diographs were made, followed by a retrograde cystogram.
Radiographic diagnosis (thorax):A diffuse increase in flu-
id density within the lungs was more prominent on the left
side. This was compatible with pulmonary hemorrhage fol-
lowing trauma. Pleural fluid was minimal but thought to be
present bilaterally. The diaphragm appeared to be intact and
the thoracic wall did not show any signs of injury. The caudal
vena cava was enlarged.
3

Radiographic diagnosis (abdomen): Peritoneal fluid was
indicated by the loss of contrast between the peritoneal organs
and by the air-filled bowel loops appearing to float on the “sea
of fluid”. The abdominal wall could not be seen clearly and
the urinary bladder was unidentifiable. A fracture through the
right half of the sacrum in conjunction with the right pubic
and ischial fractures made the right hemipelvis free of bony at-
tachment. The hip joints were normal. The change in align-
ment between the vertebral bodies of L6 and L7 seen on the
lateral view was thought to be congenital and not post-trau-
matic.
왘왘
Urethral injury 257
3

Radiographic diagnosis (retrograde urethrogram): The
retrograde study confirmed a urethral or bladder neck tear.
Treatment/Management: A more diagnostic study could
have been made if the catheter tip had been positioned with-
in the urethra, and if the study had been made immediately
following injection of a minimal amount of contrast agent.
The owner refused treatment and the cat was euthanized
without any further examination.
3

Case 3.31
Signalment/History: “Natasha” was a 3-year-old, female
DLH cat who had had an ovariohysterectomy two years ear-
lier.
Physical examination: Abdominal masses had been palpat-
ed on a recent physical examination. They continued to be
present at presentation.
made.
Radiographic diagnosis:Two mummified feti occupied the
midportion of the abdomen. A third mineralized mass was lo-
cated just cranial to the feti on the abdominal floor and a
fourth mass was located adjacent to the right abdominal wall.
Comments: The feti could have spilled from the uterus dur-
ing the ovariohysterectomy or may have been present as an ex-
tra-uterine pregnancy.
Urethral injury 259
3

Signalment/History: “Charlie” was a 2-year-old, male
DLH cat with a history of hematuria and frequent urination.
Physical examination: The bladder did not move on palpa-
tion, but was fixed against the ventral abdominal wall.
Radiographic procedure: A routine abdominal study was
performed, followed by an intravenous urogram.
Radiographic diagnosis (abdomen): The urinary bladder
was elongated and flattened with an unusual shape suggesting
that a persistent urachus or adhesions from another cause had
tied the bladder to the ventral abdominal wall.
Radiographic diagnosis (intravenous urogram): Both
kidneys functioned normally with contrast agent flowing into
the urinary bladder. The cranial tip of the bladder had a thick-
ened wall indicative of a chronic cystitis secondary to incom-
plete empting because of the uracheal remnant. The bladder
neck was not normal in appearance. It had a ventral angulation
and the gently tapering neck could not be seen. These findings
lead to a special compression study being done.
Case 3.32
Radiographic diagnosis (compression study): A com-
pression view of the bladder neck showed a radiolucent line
from a retained catheter that extended from the lumen of the
bladder into the proximal urethra (arrows).
Treatment/Management: The owner was reluctant to re-
veal the complete medical history of the cat and chose to re-
fuse to offer any explanation of the retained catheter.
3

Urethral injury 261
3
Intravenous
urogram
Compression
study

Case 3.33
Signalment/History:“Blue” was a 3-year-old, female Great
Dane with a history of surgical repair of a perianal fistula three
months previously.
Physical examination: Drainage from a perianal tract was
evident on presentation.
Radiographic procedure: Studies were made of the pelvic
region and injection of the draining tract with a positive con-
trast agent was performed.
Radiographic diagnosis: The rectum was constricted 3 cm
from the anus. No evidence of skeletal injury could be seen.
The positive contrast agent injected into the tract filled mul-
tiple saccules within the perianal tissue, principally on the
right side. Importantly, the contrast agent identified a fistulous
tract that entered the rectum (arrows), where it partially sur-
rounded the fecal material.
Treatment/Management: The case was treated medically
without good recovery. The owners rejected the offer of sur-
gical correction feeling that the first surgery should have been
successful.
3
Noncontrast

Urethral injury 263
3
Contrast

Case 3.34
Signalment/History: “Nola” was a 4-year-old, female Ger-
man Shepherd Dog being examined because of problems re-
lated to past pregnancies in which only a small number of pup-
pies had been produced, some of which were nonviable.
Radiographic procedure: Studies of the abdomen were
made, followed by contrast studies of the uterus.
Radiographic diagnosis: Intraperitoneal air was noted in
large pockets (arrows). An enlarged splenic shadow was seen.
Radiographic diagnosis (contrast study): A catheter was
placed into one uterine horn and an oily contrast agent was in-
jected. The radiographs showed intraperitoneal spread of the
contrast agent indicative of a uterine tear.
Radiographs made four days later showed a delay in the ab-
sorption of the contrast agent. An iodinated product in a wa-
ter base such as used in urography would have more resorbed
quickly.
Treatment/Management: The patient was treated medical-
ly. It is interesting that “Nola” delivered seven viable puppies
three months following the detection of the uterine injury.
3
Noncontrast

Urethral injury 265
3
Contrast

3.2.8 Postsurgical problems
Case 3.35
Signalment/History: “Tilly” was a 7-year-old, female
Yorkshire Terrier. A post-dystocia ovariohysterectomy had
been performed eight days earlier at the referring hospital. A
second operation at the same hospital was performed four days
afterwards and had been required to remove both incorrectly
placed aortic and ureteral ligations. Normal renal function did
not return and “Tilly” was referred for studies to evaluate her
renal function.
Radiographic procedure: Radiographic studies of the ab-
domen were performed, followed by a urogram.
Radiographic diagnosis (noncontrast): An overall loss of
serosal detail was thought to be secondary to postsurgical effu-
sion, peritonitis, or urine leakage. Multiple, metallic staples
were present along the ventral abdominal wall. ECG pads
were noted on the lateral abdominal wall.
3
Noncontrast

Radiographic diagnosis (urogram): A hydronephrosis of
the right renal pelvis and hydroureter of the right proximal
ureter were probably a consequence of the ligated ureter.
Leakage of contrast agent from the right mid-ureter into both
the retroperitoneal and peritoneal spaces indicated a ruptured
ureter (arrows). The left kidney and ureter appeared to have
near-normal function. The persistent loss of serosal detail con-
tinued to suggest peritoneal fluid due to postsurgical effusion,
peritonitis, or urine leakage. The balloon tip of a Foley
catheter lay within the urinary bladder (arrow).
Treatment/Management: Because of the ureteral injury, a
right nephrectomy was performed and “Tilly” was eventually
discharged to her owners.
Postsurgical problems 267
3
Urogram

Case 3.36
Signalment/History: “Smokey” was a 12-year-old, female
German Shepherd with abdominal pain.
Physical examination: A mid-abdominal mass was palpat-
ed.
made.
Radiographic diagnosis (day 1): A 4-cm, right-sided,
fluid-dense mass situated in the caudal abdomen had flecks of
calcification scattered throughout it, suggesting a granuloma
or tumor. The loss of contrast between the abdominal organs
indicated a minimal fluid accumulation that might have been
due to an effusion, hemorrhage, or peritonitis. No bowel dis-
tention was evident. The right renal shadow appeared smaller
than expected.
3
Day 1

Radiographic diagnosis (day 6): The radiographic features
were the same as on day 1. The mass lesion had stayed in the
same location within the abdomen.
Treatment/Management: The mass lesion was removed
surgically and was a retained surgery sponge incorporated
within multiple adhesions.
Comments: Abdominal tumors in general do not contain
mineralized tissue, which are more suggestive of a chronic in-
flammatory lesion.
Postsurgical problems 269
3
Day 6

4.1 Introduction
Trauma is defined as a suddenly applied physical force that re-
sults in anatomic and physiologic alterations. The injury varies
with the amount of force applied, the means by which it is ap-
plied, and the musculoskeletal organs affected. The event can
be focal or generalized affecting a single bone or joint, or mul-
tiple sites. The effect of the injury to the musculoskeletal sys-
tem can vary and result in a patient with apparently minimal
injury characterized by lameness or inability to bear weight, a
patient who is paralyzed, or a patient who is in severe shock.
The patient may be presented immediately following the trau-
ma or presentation may be delayed because of the absence of
the animal from home or because of the hesitancy or inability
of the owners to recognize the injury.
Most trauma cases are accidents in which the patient is struck
by a moving object such as a car, bus, truck, or bicycle. The
nature of the injury varies depending on whether the patient
is thrown free, crushed by a part of the vehicle passing over it,
or is dragged by the vehicle. Other types of trauma result from
the patient falling with the injury depending on the distance
of the fall and the nature of the landing. A unique injury oc-
curs when dogs jumping from the back of a moving vehicle fall
only a short distance, because the trauma results from the an-
imal hitting the road at a high speed. This type of injury is se-
verely complicated when the animal has been restrained by a
rather long rope or leash in the back of the truck, which caus-
es the patient to be dragged behind the vehicle and a form of
“degloving” or “sheering” injury results. Other possibilities of
trauma occur when the patient has been hit by a falling ob-
ject, or is kicked or struck by something. Bite wounds consti-
tute a frequent cause of injury in both small and large patients
and can be complicated by a secondary osteomyelitis that de-
velops later. Penetrating injuries are a separate classification of
injury and can be due to many types of projectiles. Gunshots
are a most common cause of trauma in certain societies (see
Chap. 6). Abuse is a specific classification of trauma and
should be suspected in certain type of injuries (see Chap. 7).
Emergency cases, i.e. those that are life threatening, are not fre-
quently seen as the result of musculoskeletal injury. A special
groupconsistsofthosepatientswithspinalinjuries,whereemer-
gency treatment may be required and a specific method of
movement of the patient is necessary in order to avoid addition-
al injury to the spinal cord. Patients with head injuries are un-
common,thoughsuchtraumasoftenresultinthedeathofthean-
imal. If the trauma only affects the more rostral portion of the
head,itresultsininjurytothenasalorfrontalportionsandthein-
jury, while obviously deforming, is not usually life threatening.
Musculoskeletal radiology can be performed relatively cheap-
ly, quickly, and safely, thus providing rapid results on which to
base the next set of decisions. Radiographic studies can usual-
ly be made on the non-sedated or non-anesthetized patient.
When and how to use these techniques is often rather obvious
(see Table 4.1).
Table 4.1: Use of radiographic examination in a traumatized or
emergency patient suspected of having musculoskeletal
injury
1. Radiograph permits selection of the area to study
a. possible to survey the entire body:
I. when a complete clinical history of the trauma is not available
II. when a thorough physical examination cannot be conducted
III. more accurately than is possible by physical examination alone
b. possible to limit study to the area of suspected injury only
c. use of comparison studies is helpful in skeletally immature patients
d. nature of injury may limit the study to a single projection
2. Radiography can be performed
a. in a non-traumatic manner
b. within a few minutes
c. with minimal cost to the client
d. with relative ease in many patients
3. Radiographic diagnosis permits the detection of
a. more than one lesion
b. which lesions are of greatest clinical importance
4. Radiographic diagnosis enables decisions to be made about:
a. the sequence of treatment
b. the prognosis
c. the expected time and cost of treatment
5. Radiography identifies complicating factors such as
a. pre-existing
I. non-traumatic lesions
II. traumatic lesions
III. arthrosis in the injured limb
b. soft tissue injury
6. Radiography provides a permanent clinical record to enable:
a. an owner to better understand
I. the lesions
II. the proposed treatment
b. the clinician
I. to evaluate the treatment
II. to review the radiographs
III. to seek further assistance by referral of the radiographs to an expert
7. Radiography permits
a. assessment of the effectiveness of therapy in the event that clinical
improvement is delayed
b. determination of the time for removal of fixation devices
c. determination of the time of discharge from the clinic
d. determination of the time for a return to full physical activity
270 Radiology of Musculoskeletal Trauma and Emergency Cases
4
Chapter 4
Radiology of Musculoskeletal Trauma and Emergency Cases

Radiology is the most commonly used method of examination
of a traumatized patient with a suspected injury to either bone
or joint. The use of radiology varies with the nature of the in-
jury and ranges from a single survey radiograph to the use of a
contrast study such as myelography in a suspected spinal in-
jury. Radiology used in the evaluation of suspected injury to
the appendicular skeleton is common and those patients con-
stitute the major portion of this section.
The physical examination in fracture/luxation cases is inform-
ative and helps direct the radiographic examination. Bite and
gunshot wounds have associated soft tissue lesions that are sug-
gestive of those types of trauma. In certain patients unable to
bear weight on a limb, attention is obviously directed toward
that limb. In those patients with a less severe injury or chron-
ic lameness, the role of trauma is not as obvious and many
types of bone or joint disease could be the cause of a lameness
incorrectly thought to be the result of trauma. Often, the
physical examination in a trauma patient is compromised be-
cause of pain or non-cooperation, and errors in interpretation
are frequent. The greatest error made in the examination of
trauma patients is the tendency to direct all attention to the
site of the most obvious injury and limit the examination of
the remainder of the animal. For example, this can lead to the
diagnosis of a pelvic fracture while ignoring a ruptured urinary
bladder, or the treatment of a femoral fracture while ignoring
a diaphragmatic hernia. The nature of the trauma can indicate
the requirement for whole body radiographs. This need de-
pends on the questionable nature of the clinical history and
your failure to obtain adequate information from your physi-
cal examination. The positive value of whole body radiographs
cannot be overstressed.
The most informative radiographic technique in the evalua-
tion of suspected musculoskeletal injury includes two views
and includes the joints both proximal and distal to the site of
the suspected injury. In an examination performed on a skele-
tally immature patient, comparison radiographs of the oppo-
site limb make the evaluation of the growth regions in a bone
more accurate. Because of the trauma, positioning of a limb in
the usual manner for radiography may be painful or damaging
to the surrounding tissues and compromises are often required.
It may be better medicine to rely on the radiograph of a mal-
positioned limb rather than having to fight with the patient in
an effort to achieve a more acceptable radiographic position-
ing. Positioning errors are especially frequent with pelvic and
femoral injuries, where the perfect VD view with the pelvic
limbs extended is too painful and it has therefore often to be
done with the limbs held in flexion with both in a similar po-
sition.
Radiographic diagnoses result from studying skeletal radio-
graphs that present information in a single plane, and which
includes only a descriptive gross image of the complex three-
dimensional cortical and cancellous structures found in a bone.
The radiographic image does not record the exact trabecular
and cortical anatomic details, but instead depicts photograph-
ic patterns that are produced by overlay, groupings, and accu-
mulations of large numbers of the fine and coarse trabeculae,
as well as the enclosing cortical bone. In a bone with a com-
plicated morphology, the radiographic interpretation of a le-
sion becomes more difficult.
In contrast to thoracic and abdominal trauma, radiographic di-
agnosis is more specific in trauma patients with musculoskele-
tal damage and may include a detailed description of the frac-
ture and its location in a bone. In comparison, for example, the
presence of fluid can be revealed in the thorax study of a pa-
tient, however, the type of fluid can only be speculated upon
until further tests are undertaken.
Differential diagnosis is not often necessary in musculoskeletal
trauma. However, it does become important when trauma is
superimposed over previous bone or joint disease, or when the
clinical history is incorrect and the bone lesions have not been
induced by trauma. In certain patients when indicated, this
section will include a full discussion of the differential diagno-
sis.
The treatment/management is often predictable in a trauma
patient and has usually been kept brief in the text, consisting
of a comment concerning the reduction and stabilization of a
fracture. This part of the case discussion is not explored to any
great depth in this book since it belongs more appropriately in
an orthopedic text. In other patients, the handling of the pa-
tient includes specific comments that are thought to be of in-
terest to the reader.
The outcome of the case is often known and a comment rel-
ative to this is made for the reader. When appropriate, the re-
sults of surgical biopsy or necropsy are included. In certain
cases, additional clinical history is known and presented for the
reader’s interest. However, the specific time required for frac-
ture healing is dependent on the particular injury, the status of
the patient, and the type of the fracture and method of stabi-
lization. Therefore, it is impossible to make specific statements
about the expected time for fracture healing. Generally, if a
time is offered, it only suggests the time expected for a frac-
ture of a particular type.
Discussion of the case presented might include comments on
specific changes in protocol that were of assistance in diagno-
sis, or it might include errors that were made in the manner in
which the case was handled. Apparent errors in clinical judg-
ment as seen in retrospect are actually often determined by the
lack of freedom offered by an owner as treatment of the case
progresses. Also included in the discussion are suggestions that
might have provided additional information of value in diag-
nosis or treatment.
Introduction 271
4

4.1.1 The order of case presentation
Presentation of trauma and emergency cases of the muscu-
loskeletal system is most easily divided based on the portion of
the skeletal system examined. Evaluation is easiest in bones of
the appendicular portion because they are tubular, have sharp
margins, and are projected free from overlying conflicting
shadows within soft tissues. All of these factors make detection
of injury relatively easy and consequently they are presented
first. The appendicular skeleton has been further subdivided
into the forelimb (Chap. 4.2.1.5) and pelvic limb (Chap.
4.2.1.6).
The pectoral girdle is composed of the clavicle and scapula.
Since the forelimb has no articulation with the axial skeleton
and supports the trunk by muscles only, the scapula is free to
move widely and can be radiographed with the body in dif-
ferent positions. The scapula’s attachment to the trunk is com-
posed of muscles that do not fracture, though they can tear
badly, and because of this, the scapula itself is not frequently
traumatized. The shoulder joint attaches the scapula to the
brachium, which is represented by the humerus. The elbow
joint attaches the humerus to the antebrachium consisting of
the radius and ulna. The antebrachiocarpal joint joins the ra-
dius and ulna to the forepaw or manus, which includes the
carpal bones, metacarpal bones, phalanges, and the small
sesamoid bones. Within the forepaw are the middle carpal
joints, the carpometacarpal joints, the metacarpophalangeal
joints, and the proximal and distal interphalangeal joints.
Each pelvic limb consists of its half of the pelvic girdle com-
posed of the ilium, ischium, and pubis fused at the hipbone or
os coxae and contains the acetabulum. The os coxae join the
sacrum at the sacroiliac joint. The hip joint connects the hip-
bone to the thigh, represented by the femur. The stifle or knee
joint connects the femur to the crus or that part of the
hindlimb, which contains the tibia and fibula. The talocrural
or ankle joint joins the tibia and fibula to the tarsal, metatarsal,
phalangeal, and small sesamoid bones. The bones and joints
within the hindpaw are similar to those found in the forepaw.
The axial skeleton with its unique morphology and high con-
tent of trabecular bone alters the manner of its response to
trauma and makes radiographic diagnosis more difficult. The
skull is the most complex and specialized part of the skeleton,
and is basically divided into a facial plus palatal region, and the
braincase. A radiograph of the head includes also the mandible.
This region is indeed unique because of the variation in mor-
phology that man has engineered in the creation of the vari-
ous breeds of dog and cat, making the head the most difficult
part of the body to radiograph or diagnose because of the ques-
tion of what should be considered normal (Chap. 4.2.2.2).
The vertebral column consists of the multiple, irregularly
shaped vertebrae divided into five groups: cervical, thoracic,
lumbar, sacral, and caudal (coccygeal) (Chap. 4.2.2.3). The
lumbosacral junction is of particular clinical importance. The
pelvic limb joins the axial skeleton at the sacroiliac joints. Be-
cause of the clinically important spinal cord, subarchnoid
myelography, epidural myelography, and sectional radiography
may be necessary to completely understand the various causes
of cord injury. Some lesions are limited to the pelvis alone,
while others extend from the axial skeleton to the pelvis; be-
cause of this latter situation, some cases of pelvic trauma are
included with the axial skeleton.
The ribs are attached to the spine and are therefore a part of
the axial skeleton. Injury to the chest wall has been given con-
siderable attention in the section on thoracic trauma. In the
musculoskeletal section, it will be also considered though to a
lesser degree in certain patients (Chap. 4.2.2.1).
4.1.2 Type of information gained by a
radiographic evaluation of the
skeleton in the trauma patient
Radiology is an important diagnostic tool in the investigation
of traumatic skeletal disease because good radiographic con-
trast is naturally provided between the bone and the sur-
rounding soft tissues, thus permitting the detection of even
small but clinically important lesions. Radiology not only of-
ten confirms the presence of an injury suspected from the
physical examination, but also enables an evaluation of the
severity of the trauma and so assists in determining the most
appropriate method of treatment and, importantly, making it
possible to offer a more accurate prognosis. A simple transverse
fracture of the midshaft of the femur can easily be differen-
tiated from a badly comminuted fracture of the same bone that
would require a different and more complex form of treatment
with a questionable prognosis. Radiographs can be used to
evaluate the success of treatment in the trauma patient by per-
mitting an evaluation of the healing of the fracture. A fracture
healing in an expected manner can be differentiated from one
with an unsuspected superimposed infection leading to non-
union, or one that involves delayed fracture healing associated
with unstable fixation and potentially a non-union fracture.
A radiographic study can also reveal additional traumatic le-
sions that are clinically silent. Radiographic studies can be uti-
lized to exclude a suspected diagnosis and instead, confirm a
new diagnosis that is of either a traumatic or nontraumatic ori-
gin. Finally, it is possible that radiographs can fail to detect the
cause of pain and lameness within a bone or joint, and so soft
tissue injury can then be suggested to be the cause of the clin-
ical signs.
Rarely are the radiographic features in an acute trauma patient
with skeletal damage inconclusive; however, they can be am-
biguous because of an acute trauma being superimposed over
preexisting disease such as chronic trauma or infection. Cer-
tain combinations of lesions are common because of the high
frequency of joint disease in some breeds as a result of devel-
4

opmental bone disease present prior to the trauma. In such
cases, both the diagnosis and treatment are complicated and
the prognosis is worsened.
A radiograph can offer information about critical features of a
lesion that permit aging of the traumatic event. This can be a
most important finding and can correct historical data re-
ceived from the owner that was either accidentally or inten-
tionally erroneous. Radiographs can also identify what I like
to think of as “leave me alone” lesions in which treatment may
not be indicated and only subsequent re-evaluation is recom-
mended.
Radiographic examination also provides a temporal dimension
that permits a more clear understanding of the clinical picture
as you observe the progression of change in the radiographic
features. This means that differences observed in the radio-
graphic features over time can be used to determine the effi-
cacy of treatment administered. Radiographs are used rou-
tinely to evaluate the success of fracture healing following the
use of a specific method of orthopedic surgery; however, as
stated before, this is generally beyond the scope of this atlas and
can be found more completely discussed in orthopedic surgery
texts.
4.1.3 Indications for radiography
in suspected musculoskeletal
trauma
Often, the indication for skeletal radiology is rather straight-
forward: the owner has seen the patient traumatized, or the
patient is obviously lame, or non-weight bearing on one limb,
or it has a prominent swelling on a limb. Other radiographic
examinations are: (1) a part of a soundness examination, (2)
made in the presence of known skeletal disease, (3) made to
provide information prior to proposed surgery, (4) made to
evaluate a postsurgical condition, or (5) of value in the gener-
al workup of a patient with generalized disease. Cases with
these five types of clinical indication are not included in this
atlas. The indications for appendicular skeletal radiography in
trauma or emergency cases are listed (Table 4.2).
4.1.4 Factors influencing radiographic
image quality
The quality of the radiographic image may limit your ability
to reach a diagnosis or, more significantly, increase the likeli-
hood of your making a wrong diagnosis. The quality can be
influenced by errors in several elements: (1) patient position-
ing, (2) selection of machine settings that determine radio-
graphic exposure, (3) selection of film-screen combinations,
(4) selection of cassette size, (5) improper use of a grid, and (6)
errors in film processing. There is a natural tendency to want
to deny that non-diagnostic radiographs have been produced
as a result of error in any of these elements. On evaluation of
a poor-quality radiograph, it is relatively easy to call an artifact
or normal anatomical variation a fracture resulting in a false-
positive evaluation. More commonly, a technical error pre-
vents visualization of a fracture, causing a false-negative eval-
uation.
Table 4.2: Indications for radiography in patients with suspected
musculoskeletal trauma or emergency cases
1. Pain
a. with or without heat
b. with or without crepitation
2. Lameness
a. painful (acute or chronic)
b. mechanical (acute or chronic)
3. Palpable mass
a. hard and firm suggesting fibrocartilaginous tissue
I. fixed in position
II. not fixed in position
b. soft and possibly fluctuating suggesting soft tissue hemorrhage
or edema
c. in association with a draining tract suggesting infection
4. Abnormal findings on joint palpation
a. abnormal movement
I. excessive
i) flexion or extension
ii) medial or lateral angulation
iii) rotational instability
II. limited
b. capsular thickness
c. joint effusion
d. crepitus
5. Postoperative evaluation of
a. fracture fixation and stability
b. fracture healing
c. post-traumatic joint disease
d. healing to determine time of removal of fixators
Correct patient positioning can be studied from textbooks, but
its application is learned by experience. Breed variation
strongly influences how positioning can be performed, with
the radiographs of a short-limbed chondrodystrophic breed
being more difficult to evaluate than those from a dog with
long limbs. The nature of a specific trauma can prevent the use
of recommended anatomical positioning and necessitate the
use of another position. The use of a sedative can assist in
achieving certain types of positioning and prevent patient mo-
tion during the exposure of the film, but this may be limited
by the clinical status of the patient.
Positioning for the lateral view is easiest and in most studies of
the dog and cat, the patient is recumbent and is positioned so
that the affected part lies next to the tabletop. However, soft
tissue injury may make it necessary for the affected limb to be
uppermost and so further away from the tabletop with an in-
creased object-film distance. Usually, the lateral radiographs
Factors influencing radiographic image quality 273
4

made mediolaterally or lateromedially are similar in appear-
ance.
The ease of positioning for the craniocaudal or caudocranial
view of a limb varies with the portion of the limb examined.
The proximal portions of the limb are more difficult to posi-
tion in a manner that places the bone parallel to the tabletop
and the limb may be extended or flexed to achieve a comfort-
able position The distal portions of the limb are relatively easy
to place correctly.
Patient positioning influences the possibility of a superimpo-
sition of anatomical structures that create new radiographic
patterns, which can make diagnosis of abnormalities difficult
or compromise their visualization on the radiographs; i.e. the
trachea or sternum may be positioned over the shoulders, or
the os penis in the male dog may be superimposed over the sti-
fle joint or femur if the hindlimb is flexed, or superimposition
of the small bones in the feet can make the diagnosis of carpal
and tarsal fractures difficult.
The inappropriate selection of exposure factors is rarely a tech-
nical problem in the radiographic diagnosis of trauma
to the appendicular skeleton. The radiographic technique
recommended for the axial skeleton is different from that used
for thoracic and abdominal studies with the higher kVp
technique thought to produce better diagnostic radiographs.
High kVp technique, in the range of 70 to 90, produces a
greater degree of contrast with additional shades of gray
identifiable on the radiograph, which are thought to enhance
its diagnostic quality. Selection of a high mA and short expo-
sure times is less critical in radiography of the musculoskeletal
system because movement of the patient and subsequent
degradation of radiographic detail is less likely.
The best film-screen combination for use in the radiography
of the limbs of dogs and cats involves the use of a combination
of slow speed intensifying screens and film because of the con-
sequent improvement in radiographic detail. Any increase in
the mAs settings required in the use of the slower system rarely
results in patient motion, because of the relative ease of patient
positioning for studies of the limbs. The increase in thickness
of the body when making axial skeleton studies can require
the use of a faster speed/film-screen combination, if and when
the mA capability of the machine is limited.
The cassette size selected should permit visualization of the re-
gion of interest dictated by the clinical examination. The en-
tire bone and adjacent joints should be included on the radio-
graph. It is a good rule to “include both ends of the affected
bone”. If the lesion is articular, the beam should center on the
affected joint and include the ends of the two adjacent bones.
In studies of the spine, multiple views using a smaller cassette
size are often more diagnostic than the use of one or two ra-
diographs made using large cassettes.
The use of a grid results in removal of much of the scatter ra-
diation that produces fogging of the film and loss of radio-
graphic contrast; however, its use is not required for most
studies of the appendicular skeleton of the dog or cat. If the use
of a grid is limited to anatomical parts exceeding a thickness
of 11 cm, it would only be required for the studies of the spine,
pelvis, shoulder and hip joints in the larger dogs.
4.1.5 Enhancement of the diagnostic
quality of a musculoskeletal
radiograph
Use of stress views: Often the value of a study of a joint can
be enhanced by making stressed views. The joint of interest is
hyperflexed, hyperextended, rotated, or placed in external or
internal angulation. These special views are of value in the de-
termination of the nature and extent of joint injury, in which
abnormal joint laxity or small fractures are present. Because of
a probable failure to understand the absolute limits of joint
motion, a comparison view made of the opposite unaffected
joint in a similar stressed position is often of value in diagno-
sis. Stress views of the occipitoatlantoaxial and lumbosacral re-
gions are extremely important in the diagnosis of suspected
spinal injury, but they must be made with care in trauma pa-
tients where further spinal cord injury could result from stress-
ing a vertebral instability.
Use of compression views: Compression views are made
by placing a radiolucent paddle over the area to be examined
forcing the bones next to the cassette. This technique must be
used with care in trauma patients. It is of value in studies of the
feet in the dog and cat, as it enables the phalanges to be forced
into a position where the bones are parallel to the cassette.
This technique can be used in spinal studies, but there a risk in
its use in an abdomen in which there is possible organ rupture.
So-called “paddle” studies enable placement of an assistant’s
hands further from the primary x-ray beam and are therefore
also a factor in radiation safety.
Use of additional views: Skyline views made in a proximal
to distal direction are valuable, but are usually limited to stud-
ies of the supraglenoid region of the shoulder, the olecranon
process, the femoropatellar joint, the trochlea of the talus, and
the os calcis. These views are always supplementary to the
conventional views.
While two views comprise a study for most bones and joints in
the dog and cat, additional oblique views are often of diagnos-
tic value and are commonly used in studies searching for frac-
tures in the feet.
Use of comparison studies: Frequently a radiographic fea-
ture or pattern of change is not familiar to the clinician and
confusion exists as to whether it represents a fracture. This
most often occurs in the skeletally immature patient, in whom
4

the growth plates remain cartilaginous and therefore, create
radiolucent lines suggestive of fractures. It is advisable to make
a radiographic study of the opposite limb providing you with
the opportunity to compare the two sets of radiographs and be
more certain of your evaluation.
The appearance of the physeal or apophyseal growth plates
changes so quickly during skeletal growth that in a suspected
trauma patient, a comparison with the opposite normal limb is
especially advisable. Special attention should also be given to
the size and shape of the epiphyseal and apophyseal ossification
centers. The epiphyseal center normally develops from a sin-
gle ossification center, so the size of the ossified growth cen-
ter increases with age and the margin of the ossified portion,
which can at first be irregular in appearance, eventually de-
velops a more distinct border. The “cut-back” zone in the
metaphysis of the rapidly growing bones often appears indis-
tinct, with a roughening of the cortical bone that has not had
the opportunity to model. This pattern, which is frequently
seen in larger dog breeds, is most prominent at the distal radius
and ulna, and the proximal humerus, though fortunately, it has
a bilateral symmetry.
Trauma patients can have Type 1 physeal fractures – physeal or
avusion of apophyses with only minimal displacement of the
centers of ossification. Evaluation is made easier when the op-
posite limb is radiographed and a comparison is made of the
location and appearance of the ossification centers. In those
patients with injury to a growth center resulting in a delay in
growth, the effect on the length and shape of the bone can be
assessed radiographically by making a comparison with a
radiograph of the opposite limb. This is considered absolutely
necessary prior to orthopedic correction. A film cassette of
sufficient length to include the entire bone will provide the
information required to assess an abnormality in bone length,
curvature, and rotation. Often the error in growth occurs
early and the altered length or shape of the bone is obvious. In
a more subtle injury, the difference in length between two
bones may be only in the range of 1 cm. In other cases, bone
growth is unequally delayed causing growth in the physeal
plate to be uneven, and bowing of the metaphysis/diaphysis
results. This may lead to a less prominent change that can only
be fully understood upon comparison with the appearance of
the normal bones in the opposite limb.
Thus, the use of radiographs of the opposite limb for compar-
ison is mandatory in trauma patients in which the physeal
growth plates are still open: <9 months of age in the dog; <16
months of age in the cat. These studies should be made rou-
tinely at the time of the first study if the patient’s condition
permits and later if clinical conditions warrant it.
If trauma occurs in a mature patient in whom an error in phy-
seal growth has occurred, the determination of the effect of
the trauma on the size, shape, and length of the bone needs to
be evaluated in addition to any new fracture from the recent
trauma. Again, the differentiation of the chronic growth ab-
normality from the recent trauma can be more easily achieved
when the opposite limb is radiographed, too.
4.1.6 Use of sequential radiographic
studies
Sequential radiographic studies are used to evaluate the success
of fracture stabilization and are commonly used to study the
pattern of fracture healing (Table 4.3). In addition, the effec-
tiveness of antibiotic therapy in a case of trauma-induced os-
teomyelitis can be monitored using successive radiographic
studies. An improvement in clinical signs associated with a
fracture often precedes an improvement in the radiographic
appearance of the fracture healing. Changes in bone as noted
on the radiograph occur after clinical signs of healing are not-
ed. “Follow-up radiographic studies” are used to assist in de-
termination of the time of removal of fixation devices.
Sequential radiographs need to be carefully standardized as to
the positioning and radiographic technique if the maximum
use is to be derived from such a comparison. One situation re-
quires a variation in this standardization rule: chronic lameness
associated with fracture fixation causes a rapid onset of atro-
phy of both the affected bone and muscle leading to a decrease
in the associated tissue volume and density, thus necessitating
a decrease in radiographic exposure. Without this change in
technique, subsequent radiographs will appear overexposed
making detection of early callus difficult and can result in a
failure to correctly recognize early fracture healing.
Table 4.3: Sequential radiographic studies in trauma patients
1. Fracture cases (Cases 4.59, 4.68, 4.69, 4.70, 4.71, 4.117, 4.122, 4.133 &
4.135)
a. evaluate quality of fracture reduction
b. evaluate fixation stability
c. evaluate callus formation
d. evaluate healing
e. predict appropriate time of removal of fixation devices
2. Bone or joint infection (Cases 4.58, 4.73, 4.101, 4.104, 4.136 & 4.137)
a. evaluate the effect of therapy
b. evaluate post-operative status
3. Joint disease (Cases 4.76, 4.78 & 4.132)
a. evaluate the progression of arthrosis/arthritis
b. evaluate post-operative status
Since this section of the book deals with trauma to the mus-
culoskeletal structures, the series of radiographic features or
patterns is much smaller, dealing often only with a deviation
in the shape or the bone organ. However, identification of a
pathological fracture requires the detection of a thinning of
cortical thickness, which is a pattern, found away from the
fracture.
Use of sequential radiographic studies 275
4

4.2.1 Radiographic features of
appendicular skeletal injury
Diagnostic radiology is conveniently used in clinical medicine
for the diagnosis of fractures, evaluation of fragment reduction
and stabilization, and for the determination of the prognosis of
fracture healing. A fracture within a cortical bone is best de-
fined as a lesion causing an interruption of the continuity of
the bone resulting from stress that is beyond the capacity of the
bone to withstand. The radiographic study should include not
only the joints proximal and distal to the injury, but also two
orthogonal views. Only on such a study is it possible to deter-
mine the full character of a fracture, something of the injury
to the surrounding soft tissues, and the possible involvement of
the adjacent joints. Evaluation of the soft tissues is important
because that injury indicates the level of energy of the trauma
and partially determines the healing potential of the fracture.
With severe soft tissue injury, the new extra-periosteal blood
supply that feeds the healing fracture fails to form as hoped for
and delayed fracture healing or a non-union fracture can re-
sult. Information concerning soft tissue injury is supplied by
noting the amount of swelling and hematoma formation as
well as the displacement of the fracture fragments. Detection
of interposed soft tissues that separate bony fragments is an in-
dication of a potential delay to the fracture healing. Marked
fragment over-riding or severe comminution of the fragments
are also indicators of extensive soft tissue injury and a poten-
tial delay in healing. The radiograph, at best, offers only a clue
to the extent of soft tissue injury, but despite this, it can pro-
vide valuable information in addition to that gained from the
physical examination.
4.2.1.1 Fracture classification
Bone fracture is the most common traumatic injury in the ap-
pendicular skeleton. It is helpful to know the terminology
used in the description of such fractures. Fracture classification
is based on the completeness of the fracture line, the number
of fracture lines, the location of the fragments, and the sus-
pected energy level of the injury. In addition, the underlying
character of the bone needs be evaluated to enable detection
of pathologic fractures. Fractures in the long bones are usual-
ly more easily classified than those seen in small cuboidal
bones. In addition, midshaft fractures are more easily classified
than those that affect the epiphyseal/metaphyseal region of a
bone. Fractures that disrupt the articular surface within a joint
are an additional type of injury of especial clinical importance.
The classification of the fracture may be dependent on the en-
ergy level of the injury. A fracture resulting from a low ener-
gy injury might be incomplete or complete with good appo-
sition and alignment of the fragments and little soft tissue in-
jury. This type of fracture would be expected to heal readily,
often with only minimal stabilization. A low energy fracture
may also result in a complete fracture with a slight separation
of the fragments; again with only a little soft tissue injury. A
fracture resulting from a high-energy injury often has severe
comminution and fragment displacement, as well as extensive
soft tissue injury indicating a longer healing time. Very high
energy fractures are usually caused by gunshot wounds in
which both the soft tissue and bone injury is extensive and
fragment alignment and stabilization is difficult or impossible.
Fractures seen in the skeletally immature bone include in ad-
dition to midshaft fractures, two clinically important groups:
(1) physeal and (2) apophyseal.
4.2.1.2 Orthopedic fixation devices
After fragment reduction, a series of devices may be used to
provide stability and maintain the alignment of the fragments
during the healing process. Most are made of a type of metal
alloy and are easily identified on a radiograph. These devices
include cortical or cancellous screws that can function as lag or
compression screws. The threads may be partial or complete.
Plates serve to compress, neutralize, or buttress a fracture.
Compression plates serve to place the fragments under com-
pression. Neutralization plates only protect fracture surfaces
from normal bending, rotational, and axial-loading forces.
Buttress plates are used to support bone that is unstable.
Wires are unthreaded segments of extruded wire of variable
thickness, which are drilled into the bone by placing them into
a drill as if they were drill bits. Rotational stability is provided
when more than one wire is used. Smooth wires can be placed
across a physeal plate since they are smooth and the growing
bone “slides” along the wire. The technique of placing a wire
around fracture fragments to achieve stability is called cerclage
wiring and is usually used in conjunction with another type of
fixation device. Tension-band wiring is a special technique
used to provide dynamic compression for the treatment of
avulsion type fractures and for replacing osteotomized bone
used to gain surgical exposure. Parallel wires are positioned to
provide rotational stability and reduce shearing forces between
the fragments. A figure-of-eight wire is placed on the tension
side of the bone and is anchored by passing it around the bent
ends of both wires and then passed through a drilled hole in
the bone. When physiological forces pull on the bone, the
wire carries the tensile force, which prevents separation of the
fragments, and thus transmits any compressive forces to the
bone.
Intramedullary pins have many sizes and shapes. They are
placed the length of the shaft of a tubular bone, where they
prevent angulation of the fragments. The pins may be used
singularly or stacked, or can be used in conjunction with oth-
er devices to prevent rotational deformity. External fixation
requires the use of pins that are joined externally after they are
transfixed through both cortices. A combination of pins can
be used to create a particular form of fixation. If the pins are
intramedullary, they may become “lost” within the medullary
cavity as a bone lengthens.
4

Any of these devices can be positioned with less than perfect
placement, and this should be noted on the immediate post-
operative radiograph. Following surgery, it is possible for any
of the devices to bend, break, or loosen. The influence this has
on the stability should be estimated from the “follow-up” ra-
diographs. A final radiograph made after apparent healing
helps to determine the appropriate time for removal of any or
all of the fixation devices. The use of radiography in the eval-
uation of post-surgical status or healing status of a fracture is
not explored to any great length in this book.
4.2.1.3 Post-traumatic aseptic necrosis
Post-traumatic aseptic necrosis is a characteristic lesion that
can be found at specific anatomical sites, where it is possible
for a bony fragment to be isolated and deprived of its blood
supply following trauma. This type of lesion occurs most com-
monly in the capital epiphysis of the femur in the skeletally im-
mature patient following physeal separation. The blood supply
to the femoral head passes along the joint capsule and to a less-
er degree through the cancellous bone of the neck, and an in-
jury resulting in a separation of the femoral capital epiphysis
plus tearing of the joint capsule leaves the epiphysis avascular.
In this condition, it retains its bone density and shape for some
time, while the surrounding femoral neck, and acetabulum can
undergo marked remodeling associated with disuse. Although
avascular necrosis is to be expected in injuries in the skeletally
immature patient, it may uncommonly occur with an intra-
capsular femoral neck fracture in the mature patient.
While common in the proximal femur, aseptic necrosis does
not frequently occur in the humeral head, although the epi-
physis has a similar intracapsular anatomy. The carpal and tarsal
bones may sometimes have a solitary blood supply that can be
destroyed after trauma resulting in bone necrosis, but this is
also uncommon.
4.2.1.4 Disuse osteoporosis (osteopenia)
Bone atrophy is a consequence of disuse. It is more prominent
and occurs faster in the growing patient than in the mature
one. The resorption of the bone tissue can be seen by making
a comparison of bone density either with a radiograph of the
bone made earlier or with the bone in the opposite limb. The
most obvious change is in the thickness and density of the cor-
tex. While the terminology suggests that this type of osteo-
porosis is subsequent to disuse, it must be noted that often in
fracture cases, severe demineralization takes place most promi-
nently only distal to the fracture. The loss of bone mineral
does not result in early change in the size or shape of the bone,
only in a loss of density within the cortex that, in severe ex-
amples, may lead to a remnant endosteal and periosteal line
with a lack of bone density between them. This laminar ap-
pearance requires a long time to appear. Later, the width of the
femoral neck can decrease.
An unexplained and more excessive loss of bone mineral oc-
curs in some trauma cases and is referred to as post-traumatic
osteoporosis (Sudeck’s atrophy) and results in malformed
bones that actually lose diameter and appear shrunken. A
change of this type is often noted in the metacarpal and
metatarsal bones of smaller dogs.
4.2.1.5 Forelimb injury
Scapula and shoulder joint
Injury to the scapula is uncommon, though fractures of the
spine or blade can result from a car passing over the patient’s
body. Such fractures are often linear with fragments appearing
to have been bent or folded because of the thin, flattened ap-
pearance of the bone. The radiographic diagnosis is difficult
due to the absence of disruption of strong cortical shadows
such as would be found in fractures in the long tubular bones.
Fractures involving the neck of the scapula are more important
clinically because of the muscle attachments to this region and
the possibility of fracture lines entering the shoulder joint (gle-
noid cavity). Radiography of the scapula is difficult as the VD
views are compromised because positioning of the forelimbs
places the scapula so it is projected “on end”. The lateral views
are compromised because of the overlying soft tissue and bony
shadows from the opposite limb, the spine, the sternum, the
air-filled trachea, and the contents of the cranial thorax.
One fracture of special importance is the avulsion of the supra-
glenoid tubercle. When found in the skeletally immature pa-
tient, it is an avulsion of the apophyseal center, while in the
mature patient it is a result of excessive tension on the biceps
tendon. A particular lesion found associated with chronic
trauma to the muscles in the shoulder is mineralization of the
biceps tendon and less commonly, the tendon of the
supraspinatus muscle.
왘왘
Radiographic features of appendicular skeletal injury 277
4

Case 4.1
Signalment/History: “Hash”, a 2-year-old, male Brittany,
had been hit by a car and was lame in the right forelimb.
Physical examination: Marked swelling was evident in the
brachium and palpation was difficult.
Radiographic procedure: Two views were made of the
shoulder area. The lateral one was made with the scapula dis-
placed dorsally as far as possible.
Radiographic diagnosis: A comminuted fracture of the
right scapula involved both the spine and blade with medial
and caudal displacement of the proximal fragment. Fracture
lines did not enter the shoulder joint and the humerus was un-
affected.
Treatment/Management: Recovery in this patient was
complicated by additional pelvic fractures. The scapular frac-
tures were not treated surgically. Radiographs of the thorax
were made because of the generalized trauma and were with-
in normal limits.
4

Signalment/History: “Hope” was a 5-year-old female
Springer Spaniel with a history of lameness for two weeks.
Physical examination: The lameness was prominent in the
left forelimb and examination indicated that the pain could be
elicited by palpation in the region of the biceps tendon. Flex-
ion of the left shoulder was painful. The right shoulder pal-
pated without pain.
Radiographic procedure: Lateral views were made of both
shoulder joints.
Radiographic diagnosis: On the left, a roughened pe-
riosteal surface extended through the supraglenoid tubercle up
to the coracoid process with adjacent small, mineralized frag-
ments and represented a chronic tearing or avulsion of the bi-
ceps tendon (arrow). A similar pattern was present on the right
shoulder, however, with much less prominent changes.
Slight periarticular spurring on the caudal aspect of the
humeral head where it meets the humeral neck was considered
an early sign of arthrosis in both shoulders.
Case 4.2
Treatment/Management: The biceps tendon was not
thought to be ruptured in either shoulder and the owner was
advised to control exercise hoping for satisfactory healing of
the lesion.
Comments: In discussion with the owner, it was learned that
the dog was aggressive during exercise and frequently pulled
hard on the leash. To strengthen the shoulder muscles of their
pets, some owners have been known to attach the leash to a
car and have the dog “tow” the vehicle.
Scapula and shoulder joint 279
4

Case 4.3
4

Signalment/History: “Wendy” was a large 1-year-old, fe-
male Scottish Deerhound who had run into a tree the day be-
fore.
Physical examination: Crepitation was produced by palpa-
tion of the right shoulder. The dog was depressed with shal-
low breathing at the time of examination.
with a special view of the scapula.
Radiographic diagnosis (thorax): The hyperlucent lung
fields were possibly due to the dog’s conformation in addition
to the thin chest wall. All major midthoracic vessels plus both
sides of the tracheal wall were easily identified as a result of a
pneumomediastinum. Pulmonary vessels were easily identi-
fied without any abnormal lung density.
Radiographic diagnosis (scapula): The fractures of the
right scapula extended through the lateral surface as well as
through the spine and appeared to cause a bending of the
bone. Fracture lines were not noted to enter the glenoid cav-
ity.
Treatment/Management: The hyperlucent lung fields
were the result of the conformation of the thorax; they made
the evaluation of the pulmonary vessels easier. Because of
“Wendy’s” deep chest, caution was exercised in the evaluation
of the cardiac silhouette, since minimal patient obliquity in
positioning affected the appearance of the heart. The origin of
the pneumomediastinum could not be ascertained from the ra-
diographic study. A lateral view of the cervical region and tho-
racic inlet did not indicate any injury to the upper airway or
to the esophagus. If the force of the trauma was severe, a tear
in a major bronchial wall could have produced the pneumo-
mediastinum. That etiology would not be clinically important
since the injury to the bronchial wall would heal rather quick-
ly. Due to this lack of knowledge of its specific etiology, it
was thought to be important to continue to follow the progress
of the pneumomediastinum radiographically hoping for its res-
olution.
The scapula fracture was treated conservatively.
Comments: Scapular fractures that do not invade the glenoid
cavity are often not treated surgically.
4

Case 4.4
Signalment/History: “Rogue” was a 12-month-old, male
Doberman Pinscher struck by a car and presented unable to
walk on the right forelimb.
Physical examination: Crepitus was palpated in the right
scapular region.
Radiographic procedure: Two radiographic views were
made of the shoulder and scapula.
Radiographic diagnosis: An acute comminuted fracture of
the scapula resulted in a marked displacement of the frag-
ments. The spine was separated.
The shoulder joint, underlying ribs, and adjacent lung were
radiographically normal.
Treatment/Management: The owners chose not to consid-
er treatment for “Rogue”.
Comments: The scapula in this patient was dense and the soft
tissue mass was thin permitting easy visualization of the scapu-
lar fragments especially in comparison to a similar injury in a
smaller dog who was obese.
4

Case 4.5
Signalment/History: “Buster” was a 21-month-old male
Labrador Retriever found that morning unable to bear weight
on the left forelimb.
Physical examination: Crepitus was palpated over the left
scapula.
Radiographic procedure: Radiographic views of the shoul-
der and scapula were made.
Radiographic diagnosis: A recent transverse fracture
through the neck and spine of the scapula resulted in marked
medial angulation of the proximal fragment (arrows). The
fracture through the spine extended proximally. The fracture
did not involve the shoulder joint.
Treatment/Management: Radiographs were made of the
thorax following identification of the traumatic lesion in the
shoulder. Both pneumothorax and lung contusion were iden-
tified. “Buster” was hospitalized and kept under observation
for several days. At the time of release, he remained lame, but
his breathing was felt to be near normal. Since the fracture did
not affect the adjacent joint, it was treated conservatively.
Comments: Fractures of the scapula are usually diagnosed on
the basis of a marked angulation of the fragments since there
are no prominent cortical shadows that can be disrupted.
Careful attention should be given to the glenoid cavity in a ra-
diographic evaluation because fractures extending into the
shoulder joint alter the clinical importance of the injury with
the possibility of development of a post-traumatic arthrosis.
4

Case 4.6
Signalment/History: “Domino”, a 13-month-old, female
Beagle, had been struck by a car five days earlier. She had had
severe dyspnea and shock at that time and was treated with
cage rest.
Physical examination: On presentation, the dog could not
bear weight on the right thoracic limb, though she did not
show any severe pain on palpation or movement of the limb.
The elbow region was swollen and palpation of the shoulder
joint was not thought to be normal. Injuries to both shoulder
and elbow were suspected. Breathing was thought to be nor-
mal.
right forelimb plus the thorax.
Radiographic diagnosis (thorax): A moderate bilateral
pneumothorax (arrows) was seen without pulmonary contu-
sion and with no evidence of pleural fluid. The cranial medi-
astinum showed fluid density ventrally that was causing a dis-
placement of the cranial lung lobes (arrows). In addition, a
well-demarcated fluid density extended caudally from the
base of the heart. These patterns of mediastinal fluid support-
ed the diagnosis of hemomediastinum.
A complete luxation of the right shoulder joint was noted with
the humeral head displaced cranially and medially (arrow).
4

Radiographic diagnosis (elbow): Avulsion fractures from
the olecranon could be seen with proximal and distal bony
fragments (white arrows). The small bone-like shadow just
craniolateral to the radial head is a sesamoid bone (black ar-
rows).
Treatment/Management: The pneumothorax and the
hemomediastinum both indicated injury to the lungs and me-
diastinal organs; however, neither was excessive and they re-
quired no treatment other than cage rest.
Comments: The shoulder joint luxation required reduction
in a dog of this size to avoid persistent forelimb lameness. The
elbow injury suggested tearing of the tendons of the triceps
with separation of the underlying bone tissue. The separation
of the bony fragments from the parent bone plus their small
size would complicate fragment repositioning.
4

Case 4.7
4
Noncontrast
Arthrogram

Signalment/History: “Sting” was a 14-month-old male
Rottweiler with left forelimb lameness, the owner believed
had started following some form of trauma. Questioning failed
to reveal what the owner meant by “some form of trauma”.
Physical examination: Examination of the left forelimb
produced pain, especially on flexion of the shoulder and on
extension of the elbow.
shoulder and elbow. An arthrogram of the left shoulder was
performed.
Radiographic diagnosis (shoulder): Studies of the shoul-
der showed a small bony ossicle off the caudal margin of the
glenoid cavity (arrow). The contour of the humeral head was
intact. The arthrogram revealed the ossicle to be a continua-
tion of the glenoid cavity. It also showed the bicipital tendon
to be normal.
Differential diagnosis: In retrospect, we know more about
this type of patient today than we did on the day he was ex-
amined. First, the small ossicle formed from the articular sur-
face of the scapula is a common finding in larger breeds re-
presenting an incomplete ossification of the glenoid cavity, and
while undergoing some movement, is not always indicative of
clinical signs. Second, the minimal changes in the elbows that
were ignored are diagnostic of medial coronoid disease and be-
latedly were felt to have definite clinical importance.
Treatment/Management: No treatment was offered.
Comments: “Sting” probably continued life with a progres-
sive arthrosis in the elbow secondary to the undiagnosed me-
dial coronoid disease.
4

Signalment/History: “Rocky” was a 3-year-old, male Pit
Bull Terrier struck by a car one month previously and had
been lame on the left forelimb ever since.
Physical examination: Palpation of the shoulder was painful
and movement of the shoulder joint was limited.
Radiographic procedure:Studies of the shoulder joint were
conducted.
Radiographic diagnosis: A comminuted fracture line sepa-
rated the supraglenoid tuberosity, entered the shoulder joint,
and extended approximately 3 cm proximally along the cranial
border separating the scapular notch. The larger fragment was
displaced cranially by tension on the long tendon of origin of
the biceps muscle. A single fragment was identified at the ar-
ticular surface (black arrow). Callus formation was noted on
the large fragment (white arrows), and between the large frag-
ment and the parent bone. The appearance of the fracture was
in agreement with the length of time since the injury.
Differential diagnosis: Older fractures develop a pattern of
callus that results in fragment margins appearing indistinct. A
radiographic pattern of this type invites a possible diagnosis of
a pathologic fracture. The young age of the dog plus the ab-
sence of any clinical signs suggesting infection tended to rule
out malignant disease or osteomyelitis. Still, the character of
the fracture was unique and possibilities other than simple
trauma were considered.
Treatment/Management: Because of the age and nature of
the injury, it was thought not possible to reposition the frag-
ment and it was left to heal as a malunion fracture. This was
unfortunate because of the resulting persistent disruption of
the articular surface of the scapula.
Case 4.8
4

Humerus and elbow joint
Most fractures of the humerus involve the midshaft of the bone
and the condylar region, as the proximal end seems to be well
protected by the shoulder muscles. Midshaft fractures are typ-
ically spiral and can be easily examined radiographically on a
lateral view, although positioning for the craniocaudal or cau-
docranial view may be painful and not easily performed due to
the problem of extending or flexing the limb. Distal condylar
fractures are often found in immature members of smaller
breeds. In such cases, the opposite limb needs to be examined
also, since the fracture may be associated with a persistent car-
tilage remnant that exists between the two condyles, and also
such fractures may be bilateral. In the adult, the fractures may
be linear and result in separation of the lateral condyle or may
assume a “T” or “Y” configuration and separate both
condyles. Oblique positioning may be helpful in these patients
in determining the possible entrance of a distal fracture line
into the elbow joint space.
Examination of the elbow is most often undertaken in the
search for secondary arthrosis following dysplasia. Elbow lux-
ation following trauma can occur with or without any associ-
ated fractures. Avulsion of the olecranon can occur in both
immature and mature patients, while avulsion of the medial
epicondyle only occurs in the skeletally immature, although
this type of injury in a healed form may be seen on radiographs
of a mature patient.
Case 4.9 #216936
Signalment/History: A 4-month-old, female Yorkshire
Terrier had been bitten by a dog several days previously. She
had been non-weightbearing on her left foreleg since that
time.
Physical examination: Examination revealed crepitus in the
upper left foreleg that suggested a humeral fracture.
left thoracic limb.
Radiographic diagnosis: A simple, slightly oblique fracture
at the junction of the middle and distal thirds of the humerus
had resulted in overriding of the fragments with marked in-
stability. Both the shoulder and elbow joints were radiograph-
ically normal.
Treatment/Management: The fracture was treated with a
single IM pin. Later, the distal fragment displaced cranially and
the pin escaped from that fragment.
The owner would not spend any additional funds on treat-
ment and they departed in an unhappy mood with an unsta-
ble fracture that at the best would become a malunion.
Comments: A fracture of this type without any degree of
comminution is unique and represents a low energy fracture
that, considering the age of the patient, would have healed eas-
ily had the stabilization been adequate.
Humerus and elbow joint 289
4

Signalment/History: “Cream” was a 20-year-old, female
Siamese cat with lameness thought to be secondary to trauma
that had occurred eight to ten weeks earlier.
Physical examination: The right elbow was painful on pal-
pation and motion was limited. No soft tissue swelling was
noted.
right elbow.
Radiographic diagnosis: Marked periarticular new bone
was attached to the parent bone and was in the form of peri-
articular osteophytes as well as enthesophytes. The new bone
was centered near the medial coronoid process of the ulna, as
well as cranially at the humeral condyle and radial head. Note
the modeling (flattening) of the articular surface of the humer-
al condyle.
Differential diagnosis: The pattern of new bone that char-
acterized the chronic degenerative joint disease in this old cat
was similar to that seen in dogs with medial coronoid disease.
While a pattern such as this could have resulted from acute
trauma, it is more likely that the trauma to the joint was min-
imal and repetitive. The lesion does not have the characteris-
tics of inflammatory arthritis.
Treatment/Management: Little was offered in a way to
treat this chronic arthrosis and “Cream” was not seen again af-
ter this visit to the clinic.
Comments: Patients such as this older cat with chronic
arthrosis often are seen in the clinic following minimal trauma
with an apparent acute lameness while the lesion, as identified
radiographically, suggests a duration of months or years. Cats
especially have the tendency to not show any clinical signs; i.e.
pain, relative to chronic joint disease of this type until the time
of a superimposed trauma.
Case 4.10
4

Case 4.11
Signalment/History: “Mutley” was a 3-year-old male
Labrador Retriever who had a luxation of the right elbow; the
result of a dog bite nine months earlier. Radiographs were
made at that time and demonstrated the luxation that was re-
duced by closed reduction.
Physical examination: On presentation the joint was
swollen and the dog did not use the limb normally. Motion of
the elbow joint was limited and a firm soft tissue swelling sur-
rounded the joint.
Radiographic procedure: The elbow joint was re-radio-
graphed to determine the status of the joint at this time.
Radiographic diagnosis: Destruction of the elbow joint
was characterized by fragmentation of the anconeal process,
flattening of the trochlear notch, periarticular lipping from the
medial coronoid process, and periarticular soft tissue mineral-
ization. The lesion was considered a severe post-luxation
arthrosis.
Differential diagnosis: The new bone formation on the
bone margins suggested the possibility of an inflammatory
process, and both an osteomyelitis and infectious arthritis were
considered. To see this lesion without a history of trauma, a
diagnosis of malignant synovioma could also be considered.
The bony features seen on the radiograph are typical for a
chronic elbow dysplasia except for the periosteal new bone
and the fragmented anconeal process
Treatment/Management: Surgical arthrodesis was per-
formed. No evidence of infectious or neoplastic tissue was seen
at surgery.
Outcome: Radiographs made six weeks post-operatively
showed a successful joint arthrodesis and the dog could use the
limb without pain.
Comments: This was an interesting patient with atypical el-
bow disease that necessitated surgical intervention to provide
tissues to rule out the possibilities of either inflammatory or
neoplastic disease. Surgical arthrodesis is thought to be a satis-
factory treatment for a post-traumatic joint disease of this type.
4
On presentation Six weeks postoperative

Case 4.12
Signalment/History: “Woody” was a 10-year-old, female
cat with a history of limping on the right forelimb for some
weeks.
Physical examination: Neither crepitus nor pain were pal-
pated and the cat did not show any lameness in the examina-
tion room.
Radiographic procedure: Both forelimbs were radio-
graphed.
Radiographic diagnosis: The malformed medial epi-
condyles had enthesophytes originating at the origin of the
carpal flexors and adjacent soft tissue mineralization probably
the result of avulsion fractures (black arrows). The mineraliza-
tion had a smooth margin and was adjacent to the entheso-
phyte formation. No joint disease was evident. All of the in-
jury was chronic.
The sesamoid bones within the lateral collateral ligament were
identified adjacent to the radial head bilaterally (white ar-
rows), at the site where they blended with the annular liga-
ment.
Differential diagnosis: While the clinical history suggested
recent trauma, the radiographic features were those of chron-
ic injury.
Treatment/Management: No treatment was considered in
this patient.
4

Signalment/History: “Issac” was a 2-year-old, male Irish
Setter, who had injured his left elbow when struck by a car.
Physical examination: A severe laceration on the lateral as-
pect of the left elbow indicated marked soft tissue injury. The
soft tissue swelling was severe.
Radiographic procedure: Studies were made of the left el-
bow.
Radiographic diagnosis: The debriding injury was not ful-
ly appreciated on the physical examination, but was obvious
on the radiograph after noting that the lateral epicondyle was
flattened after having been “ground away”. Small fragments of
bone or foreign material (black arrows) remained in the soft
tissues lateral to and cranial to the joint. The three bones form-
ing the elbow joint remained in their normal anatomical po-
sition; however, the soft tissue injury, at least, must have de-
stroyed the lateral collateral ligament.
Treatment/Management: A shearing injury of this nature
requires surgical skill to repair the soft tissue damage. The ap-
parent absence of fracture fragments mistakenly suggests that
this was an injury, which would heal without problems.
Unfortunately, the owners chose to take “Isaac” home and the
nature of the natural, untreated, repair of the elbow joint was
not known.
Case 4.13
Comments: The use of stress radiographs would have shown
other features of the soft tissue injury; however, care must be
exercised in determining which patients should have stress
studies to prevent further damage to the soft tissues.
4

Radius and ulna
Fractures of the radius are common because of its distal loca-
tion on the forelimb and are found with associated fractures in
the adjacent ulna. Dependent on the injury, the fractures may
be within the same part of the radius and ulna. If the injury re-
sults in a rotational deformity to the limb, one fracture may be
proximal and the other distal (Table 4.4).
Fractures of the ulna are uncommonly found alone, but are
usually associated with a concomitant fracture in the radius.
Because the ulna is the smaller of the two bones, treatment of-
ten is directed toward the larger bone and the ulna may be left
untreated. In the mature patient, fracture lines through the
olecranon appear differently from those seen in the more tu-
bular-shaped portion of the bone. Injury to the proximal ulna
can lead to an avulsion of the apophyseal growth center of the
olecranon in the immature patient. Injury to the distal ulna in
the adult can result in the fracture of the styloid process.
Physeal injury may result in either bone from a relatively mi-
nor, clinically unimpressive injury, with a subsequent effect on
bone growth from either the proximal or distal growth plates.
The trauma may result in premature closure or only delayed
growth, either being of equal or unequal influence across the
plate. Such injuries lead in the worst situation to a shortening
or a marked angulation of the bone. This is usually associated
with an injury to the elbow or antebrachiocarpal joints. The
result of trauma to the distal ulna is unique and often causes
injury to the cone-shaped physeal plate where lateral move-
ment of the metaphysis occurs with a crushing injury to the
physeal plate. Because 90% of the ulnar growth results from
this distal growth plate, any injury at this location can marked-
ly affect the subsequent length of the ulna. Often the disturb-
ance in growth affects more than one growth plate and it may
be difficult to ascertain, which was a primary effect from the
acute trauma and which was the secondary effect from the dis-
parity in length of the adjacent bone.
Table 4.4: Radiographic signs of trauma to the radius and ulna
1. pattern of fractures of the radius alone
a. uncommon
b. occurs with
I. minimal trauma causing incomplete fractures (Case 4.18)
II. gunshot injury
III. degloving injury (Case 4.30)
2. pattern of fractures of the ulna alone
a. uncommon
b. occurs with
I. fractures of the olecranon
II. avulsion of the olecranon apophyseal growth center
III. fracture of the styloid process (Case 4.19)
3. pattern of radial and ulnar fractures (Case 4.15)
a. common
b. midshaft spiral or comminuted with butterfly fragments
c. fragment appearance dependent on type of trauma (Case 4.30)
4. abnormal post-traumatic growth (Case 4.125)
a. proximal radial physis
I. shortening of the radius
II. widened humeroradial joint space
III. destruction of the trochlear notch of the ulna (Cases 4.124 & 4.126)
b. distal radial physis
I. shortening of the radius (Case 4.126)
II. widened radiocarpal joint space
III. destruction of the radiocarpal joint space (Case 4.124)
c. distal ulnar physis
I. shortening of the ulna (Cases 4.100 & 4.127)
II. proximal displacement of the styloid process
III. lateral rotation of the foot
IV. valgus deformity of the foot
V. destruction of the antebrachiocarpal joint (Case 4.125)
d. combination of growth anomalies (Case 4.17)
I. proximal and distal radial physes
II. distal radial and ulnar physes
4. non-union fracture (Cases 4.114 & 4.118)
5. pattern of soft tissue injury
a. subcutaneous emphysema
b. surface debris
c. gunshot missile pattern
4

Signalment/History: “Saul” was a 7-month-old, male Pug
cross who had been limping for 24 hours.
Physical examination: Forelimb lameness was evident on
observation and the dog only placed partial weight on the af-
fected limb. Pain was evident on palpation of the left forelimb
distally. No evidence of a malalignment of the bones was not-
ed. No crepitus was noted. Soft tissue swelling was minimal if
present at all.
Radiographic procedure: Two views were made of the dis-
tal part of both limbs.
Radiographic diagnosis: A break in the cortex at the junc-
tion of the middle and distal thirds of the left radius had re-
sulted in a fracture with a slight cranial and lateral angulation
of the distal fragment. This was an incomplete radial fracture.
The ulna appeared unaffected. Both adjacent joints were
within normal limits. All the growth plates were open. The
right forelimb was normal in comparison.
Case 4.14
Treatment/Management: Because of the incomplete na-
ture of the fracture, it was treated by splinting.
Comments: The owner of a young patient with skeletal trau-
ma should be advised to examine the limbs regularly after in-
jury to determine the first display of growth abnormality,
which probably will present as a lateral angulation of the foot.
At the time of detection of any growth abnormality, radio-
graphs can be made to determine the specific status of the
physeal growth plates and a projected severity of the disparity
in growth.
Radius and ulna 295
4

Case 4.15
Signalment/History: “Tar Baby” was a 14-month-old,
male Greyhound who had suffered fractures in both forelimbs
while playing.
Physical examination: The fractured limbs had been splint-
ed and the extent of the examination was compromised by the
presence of the splinting material.
Radiographic procedure: Both views were made of each
forelimb.
Radiographic diagnosis: The fractures were simple and in-
volved both the radius and ulna on each of the forelimbs. The
fracture site on the left was midshaft, while the fractures on the
right were more distal. Overriding at the fracture site resulted
in an absence of any end-to-end apposition of the fragments.
Soft tissue swelling was minimal. The quality of the radio-
graphic studies was compromised only slightly by the overly-
ing splint. Both the elbow and carpal joints were normal bi-
laterally.
Differential diagnosis: Because bones in both forelimbs
were fractured, a search was made to detect a cause of bone
weakness. However, the bone tissue was thought normal in
density, with normal cortical thickness and pathologic frac-
tures were not considered likely.
Treatment/Management: The radial fractures were stabi-
lized with intramedullary pins achieving relatively good frag-
ment alignment. Callus formation was exuberant indicating
that the fixation was permitting some movement at the frac-
ture site. Radiolucencies were noted around both IM pins and
both movement of the pin or osteomyelitis were suspected.
Outcome: Subsequent radiographs made at ten weeks indi-
cated that the fractures had healed, but certainly following sec-
ondary healing. The suspect radiolucencies identified around
the pins were proven to be due to their movement and not a
bone infection.
4
Right Left Right Left

Case 4.16
Signalment/History: “Mimi” was an 8-month-old, female
Pomeranian who could not walk on her forelimbs. Trauma
was thought to have occurred several days before.
Physical examination: Crepitus and instability were easily
palpated in each forelimb.
Radiographic procedure: Two views were made of each
forelimb.
Radiographic diagnosis: The radial and ulnar simple
oblique fractures on the left were at the junction of the mid-
dle and distal thirds of the bones. The fractures showed signs
of modeling at the fragment ends although no bridging callus
could be seen, indicating a somewhat longer time period since
the trauma than the reported period of several days.
Almost identical fractures were present on the right; however,
the fracture fragments in that limb were sharply marginated
with no modeling indicating a more acute injury.
Differential diagnosis: Bilateral fractures without a clinical
history of trauma always suggest the possibility of pathologic
fractures. In this patient, the bone density and thickness ap-
pears relatively normal for the breed and the fractures were
thought to be due to a minimal trauma of low energy such as
jumping to the ground from a short distance.
Treatment/Management: The owner chose to return to
their referring veterinarian for treatment and this interesting
case was lost to follow-up.
Comments: The explanation of fractures in both limbs that
appeared to be of different ages remained confusing at the
time of first examination. However, prior to leaving the clin-
ic, the owner did admit that “Mimi” had been lame on the
left forelimb a period of several days before the injury to the
right limb. This suggested two separate traumatic events and
explained the difference in the appearance of the fractures.
Radius and ulna 297
4

Case 4.17
Signalment/Management: “Tory” was an 11-month-old,
female Boxer with an uncertain past history of fractures in the
forelimbs occurring three months before. Recently, the own-
er noticed that “Tory” was lame on the left forelimb after ex-
ercise.
Physical examination: A valgus deformity was noted in the
left foot and cranial angulation of the right forelimb as the dog
stood in the examination room. She could move easily and did
not show any pain on walking. Palpation of the distal portion
of each forelimb located several prominent hard, firm masses
of uncertain etiology that were not painful and were not asso-
ciated with any overlying soft tissue swelling.
Radiographic procedure: Radiographs were made of both
forelimbs because of the patient’s age and the clinical findings.
Radiographic diagnosis (day 90 after the presumed
trauma): Cranial angulation of the distal radius and ulna was
noted on the right forelimb at the site of the pedunculated
bony mass. A valgus deformity of the left antebrachium was
prominent and a pedunculated bony projection appeared to
originate from the radius at a site where lateral angulation of
the distal fragment occurred. The bony projections appeared
to originate from the radius and to cause underlying cortical
defects in the adjacent ulnae bilaterally. It was difficult to de-
termine the presence of bony activity at this time. The extent
of injury to the antebrachiocarpal joints could not be clearly
determined, but was thought to be only minimal.
Differential diagnosis: The pedunculated bony masses had
the appearance of benign tumors: multiple osteochondromas.
While not seen frequently, these benign bony tumors may re-
sult in a growth abnormality in the parent bone especially
when located near the end of a bone. The history of past trau-
ma falsely suggested that the lesions could have been the result
of malunion fractures. Fortunately, radiographs made at the
time of the injury provided the answer.
4
Day 90 after trauma

Radiographic diagnosis (day of presumed trauma):
Subsequently, it was possible to review the radiographs that
were made on the day of the presumed trauma. In these, trans-
verse fractures in the radius and ulna in both forelimbs were
obvious with an overriding of the fragments.
Comments: A review of the original radiographs clearly
showed the patterns seen on presentation to be the result of
malunion fractures. While the fractures had healed, the angu-
lation in the bones created a clinically important problem for
this dog.
Radius and ulna 299
4
Day of trauma

Case 4.18
Signalment/History: “Scarlet” was a 6-month-old, female
Irish Setter, who had been struck by a car earlier in the day and
was presented non-weightbearing on the right thoracic limb.
Physical examination: The right forelimb was painful to
touch especially in the distal portion; however, no crepitus
was detected. Swelling was minimal. Movement of the joints
appeared normal, but painful.
Differential diagnosis:A witness to the injury simplified the
differential diagnosis and a fracture/luxation in the forelimb
was strongly suspected.
Radiographic procedure: Two views were made of the in-
jured forelimb.
Radiographic diagnosis (day 1): An incomplete, “green-
stick”, fracture extended through the midshaft of the right ra-
dius (black arrows). Apposition and alignment of the frag-
ments remained anatomical. The right ulna was not fractured.
Fracture lines did not enter the physeal growth areas. The ad-
jacent joints were radiographically normal.
Note the heavy bony “cuff” that encircles the distal ulnar
metaphysis, a normal finding in larger dogs at this stage of
skeletal growth (white arrows).
Treatment/Management: Because of the patient’s age
and the incomplete nature of the fracture, the limb was only
splinted.
A second set of radiographs was made three weeks later.
Radiographic diagnosis (week 3): The fracture was in a
healing phase with the fracture line bridged with callus and not
visible. Note the smooth periosteal callus (arrows). Also note
the disuse osteopenia characterized by thin dense lines that in-
dicate the cortical width especially around the small bones dis-
tally. The growth plates all remained open indicating that the
injury had not affected bone growth.
Comments: Disuse osteopenia occurs quickly in the imma-
ture patient.
4
Day 1 Week 3

Case 4.19
Signalment/History: An 11-year-old, female colony Beagle
was examined at necropsy for the possible spread of malignant
disease.
Radiographic procedure: Radiographs were made of all
the bones.
Radiographic diagnosis (postmortem): A distal ulnar le-
sion on the left forelimb showed evidence of cortical thicken-
ing with a radiolucent zone in the medullary cavity partially
surrounded by bony tissue (black arrow). The periosteal sur-
face was smooth. The soft tissues were not swollen when com-
pared with the opposite limb.
Differential diagnosis: The lesion could be either an in-
flammatory or neoplastic lesion; however, the lesion showed
no evidence of any activity as would have been indicated by
new bone formation. The possibility of a healed fracture
should be considered.
Radiographic diagnosis (9 years earlier): Radiographs
made when the dog was 2 years of age showed a unique ulnar
fracture (white arrow) at that time with a callus formation yet
to bridge the fracture site.
Comments: This dog was a colony dog and was housed two
to an enclosure. It is possible that the fracture was the result of
a bite wound. The fence construction prevented a limb being
caught with a resulting fracture. Stress fractures without dis-
placement of fragments could be considered and it was known
that the dogs spent many hours each day jumping against the
fence.
The pattern of incomplete healing was probably due to a fail-
ure of normal stress lines at the time of healing.
Radius and ulna 301
4
Postmortem Nine years earlier

Forefoot
The bony structures of the forefoot include the carpus,
metacarpus, phalanges, and the small sesamoid bones. All of
these bones are small and trauma can result in crushing or
comminution, with the impaction preventing the easy detec-
tion of fracture lines. Luxation of the intact central carpal bone
occurs in athletic dogs. Because of its morphology, multiple
views are usually made of the foot to aid in diagnosis. Anoth-
er helpful method of examination is the use of stress views in
which the foot is placed in hyperextension or in hyperflexion,
with medial or lateral stress, or in rotation. The injury to the
soft tissues supporting the joints can be detected on these stress
studies. In addition, corner fractures and avulsion fractures can
be seen more clearly.
Determining the position of the accessory carpal bone is valu-
able in the detection of injury to the flexor retinaculum or the
deep ligaments leading from the tip of the accessory carpal
bone to the heads of metacarpals IV and V.
Two prominent sesamoid bones are embedded in the tendons
of insertion of the interosseus muscles at each metacarpopha-
langeal joint on the palmar aspect and may be important in
causing pain and lameness. Injury often affects the 2nd and 7th
bones because of the angulation of those joints to the ground.
The bones can be fractured and appear with two or more frag-
ments, the sum of which approaches their original size and
shape. Congenital anomaly of these small bones can be re-
ferred to as bipartite or tripartite sesamoid bones, in which the
fragments are malformed, have a round smooth margin, and
the sum of which is usually larger than the size of a normal
bone. A third cause for apparent fragmentation of the sesamoid
bones is chronic joint disease, usually traumatic in nature, and
in which the bones become fragmented assuming multiple
sizes and shapes. The nature of the onset of pain or lameness
plus the appearance of the other sesamoid bones in the same
foot and in the opposite foot does much in assisting the deter-
mination of the correct etiology.
The third phalanx is unique as its base contains the articular
surface and the extensor tubercle. The distal part of the pha-
lanx is a laterally compressed cone shielded by the horny claw,
the root of which fits proximally beneath the ungual crest.
Because of the tendency for the dog to hold the first phalanx
extended, the second phalanx flexed, and the third phalanx
hyperextended, these bones are difficult to radiograph in a
dorsopalmar direction. Flattening of the foot through the use
of a compression paddle may be of assistance in radiography.
Separation of the digits through the use of gauze tape or a
small paddle device is helpful in taking a diagnostic lateral
view.
4

Signalment/History: “Shami” was a 3-month-old puppy
with a suspected abnormality in the left forefoot.
Physical examination: It was difficult to determine pain on
palpation, but the affected foot did have a valgus deformity.
Radiographic procedure:Dorsopalmar views were made of
both forefeet.
Radiographic diagnosis: Non-union fractures in the mid-
portion of the 2nd, 3rd, 4th, and 5th metacarpal bones permitted
lateral angulation of the distal portions of the digits (arrow).
Evidence of disuse was noted in the increased width of the
metacarpophalangeal joints due to delayed epiphyseal growth
and the increased length of the claws on the affected foot.
Differential diagnosis: The possibility of infection as a cause
of the non-union was not considered because of the absence
of any clinical signs pointing to an infectious lesion and the ab-
sence of any periosteal new bone.
More important clinically is the question of whether the frac-
tures are delayed union or non-union. The callus is smooth
and shows no activity supporting the diagnosis of non-union.
Treatment/Management: Because of the question of non-
union, the foot was re-radiographed two weeks later. The
fragments had remained in a non-union status. Small IM pins
were inserted in the 3rd
and 4th
metacarpal bones and radio-
graphs made two weeks following the surgery showed early
bridging callus.
Case 4.20
Forefoot 303
4

Case 4.21
Signalment/History: “Bucklely” was a 1-year-old, male
Wolf-Husky mix with a marked abnormality in the left fore-
foot. The owner knew nothing of the origin of the abnormal-
ity, but admitted that it had been present for many months.
Physical examination: The marked deformity in the
metacarpal bones could be palpated without pain. The soft tis-
sue was firm with a prominence laterally and without heat or
swelling. Only four digits were present.
Radiographic procedure: Multiple views of the affected
foot were made with a single dorsopalmar view of the normal
foot for comparison.
Radiographic diagnosis: Malunion fractures with cross
healing were noted in the 3rd
and 4th
metacarpal bones proxi-
mally. The proximal portion of the 5th
metacarpal bone was
present with atrophic penciling of the distal tip. The remain-
der of the 5th
digit has been amputated. On the lateral view,
the marked cranial bowing of the affected metacarpal bones
was evident.
Differential diagnosis: The etiology of the deformity was
thought to be traumatic and was associated with the amputa-
tion of the 5th
digit. Congenital anomalies have bones that are
more orderly in their development.
Treatment/Management: No treatment was offered.
Comments: This dog was presented to the clinic with a new
owner two years later with the same abnormality. The dog was
entered as a German Shepherd Dog at this time. The radio-
graphic changes in the left forefoot were identical to those not-
ed on the first study.
4
Right Left

Case 4.22
Signalment/History: “J.R.” was a 6-month-old, male
Bouves de Flanders, who had fallen a distance of 5 meters two
days earlier and was acutely non-weight bearing on the left
forelimb.
Physical examination: Palpation indicated a fracture of the
scapula on the left and in addition, multiple fractures in the left
hindfoot.
Radiographic procedure: Multiple radiographs were made
of the left foot.
Radiographic diagnosis (day 2): Salter-Harris Type 1 frac-
tures in the proximal physes of the first phalanx of all four dig-
its. The fragments were displaced medially and angled lateral-
ly
Treatment/Management: The phalangeal fractures were
treated conservatively by placement of the foot in a splint. Ra-
diographs were made 4 weeks later
Radiographic diagnosis (week 4): The bony callus bridged
the fracture in a malunion type of healing (arrow). The later-
al angulation of the bones persisted. The scapular fracture was
also healing.
Comments: Note the use of a “wooden spoon” on the sec-
ond study to assist in positioning of the foot.
Forefoot 305
4
Day 2
Week 4

Case 4.23
4
Left
Right

Signalment/History: “Tug” was a 10-year-old, male Shet-
land Sheepdog who had been lame on the left forelimb for
over one year. He had been “chewing” on the left carpus for
the previous 30 days.
Physical examination: The antebrachiocarpal region on the
left was swollen and firm without any evidence of heat. Pain
was not noted on palpation.
forelimbs.
Radiographic diagnosis: The left carpus had misshapen
carpal bones with lucent regions in the radiocarpal bone, pos-
sible fragmentation of the 1st
, 2nd
, and 3rd
carpal bones, and
marked periarticular new bone on the medial side including
the distal radius. The space between the central and ulnar
carpal bones was increased suggesting a luxation of the ulnar
carpal bone. Other intercarpal joint spaces were difficult to
evaluate. The accessory carpal bone appeared to be unaffected.
The right carpus was thought to be normal.
Differential diagnosis: The lesion was thought to be trau-
matic, but inflammatory sites as indicated by the radiolucent
pockets were considered.
In such a case, a specific form of chronic trauma should be
considered, i.e. that associated with the abductor pollicis
longus muscle whose tendon inserts on the proximal end of
the first metacarpal; although here the luxated ulnar carpal
bone is not compatible with this diagnosis.
A final consideration in distal joint disease in smaller dogs is a
polyarthritis. The radiographic features seen in “Tug” were fo-
cused on the medial aspect of the carpal region, which is a not
typical presentation for that condition, and the lesions were
only found in one joint which is not expected in polyarthritis.
Treatment/Management: Multiple joints taps were all
without evidence of inflammation. “Tug” was placed on as-
pirin and reported to have lessened lameness. The diagnosis
was post-traumatic arthrosis.
Forefoot 307
4

Case 4.24
Signalment/History: “Rocky”, a 4-year-old, male German
Shepherd, was lame on the right forelimb.
Physical examination: Prominent swelling of the 5th
digit
on the right forefoot was painful on palpation. No drainage
was noted.
of the foot.
Radiographic diagnosis: The ungal process of the third
phalanx on the 5th
digit was blunted (black arrows) and a frag-
ment of mineralized tissue in the tip of the nail (white arrows)
was thought to be a dissociated fragment that originated from
the ungual process. The lesion had the appearance of being
secondary to chronic trauma and had no radiographic changes
to suggest either an inflammatory or neoplastic process. The
lesion was diagnosed as a post-traumatic lesion. The small frag-
ment of bone adjacent to the distal interphalangeal joint space
was thought to have resulted from the traumatic event.
Differential diagnosis: A helpful diagnostic radiographic
finding was the absence of inflammatory or neoplastic features
such as periosteal new bone or amorphous soft tissue mineral-
ization.
Treatment/Management: The lesion was treated conserv-
atively with the option of amputation for sometime in the fu-
ture.
Outcome: “Rocky” developed a severe cauda equina syn-
drome 10 months later and was retired from the police force.
4

Signalment/History: “Hermann” was a 12-year-old, male
German Shepherd cross, who had had swollen forefeet for
several months. He had become noticeably lame three days
earlier.
Physical examination: Both feet were swollen, more se-
verely on the right, and were firm to palpation. Motion of the
metacarpophalangeal joints was limited with some crepitus.
No draining tracts were located.
Differential diagnosis: The bilateral involvement of both
feet alters the differential diagnosis. Both acute and chronic
trauma plus foreign body abscessation due to plant material
were considered in this patient.
Radiographic procedure: Two views of both forefeet were
made.
Radiographic diagnosis: The lesions were limited primari-
ly to the metacarpophalangeal joints of the major digits. The
joint spaces were collapsed, the subchondral bone was sclerot-
ic, prominent enthesophytes had formed at the sites of attach-
ment of the joint capsules, and some free joint bodies were
present. Periarticular soft tissue swelling was prominent. The
interphalangeal joints were normal with the exception of min-
imal change at the proximal and distal interphalangeal joints of
the 5th
digits on both feet. The nails were greatly overgrown.
Case 4.25
No destructive lesions were noted that might have been asso-
ciated with an infectious disease. All of the changes were
thought to be due to chronic trauma. The carpal regions were
normal.
Treatment/Management: The dog was treated sympto-
matically in an effort to reduce the pain and discomfort from
the chronic post-traumatic arthrosis.
Comments: The destructive changes associated with an in-
flammatory lesion superimposed over a chronic, non-inflam-
matory, post-traumatic joint disease would probably not be
easily detected radiographically. In this dog, several explorato-
ry incisions were made to learn more of the etiology and
only granulation tissue was obtained. The pattern of injury is
interesting in that the trauma was centered at the metacarpo-
phalangeal joints. Also the small centers of ossified tissue
interposed between enthesophytes (arrows) is a frequent find-
ing associated with chronic arthrosis.
Forefoot 309
4

Case 4.26
4
Right
Four months later
Left
At presentation

Signalment/History: “Butkkus” was a 7-year-old, male
Boxer with a mild left forelimb lameness for four months.
Physical examination: Swelling was present on the medial
aspect of the radiocarpal joint, associated with pain on palpa-
tion of that region.
of both carpal joints.
Radiographic diagnosis (left carpus): A radiolucent line
with irregular borders extended proximodistally through the
center of the radiocarpal bone and suggested a chronic fracture
as seen in primarily trabecular bone (black arrow). A small
bony fragment was present dorsally at the radiocarpal joint
(white arrow). The injury to the articular surfaces was diffi-
cult to see, but must have been rather extensive since the frac-
ture line extended into the joint spaces both proximally and
distally. Adjacent soft tissue swelling was noted.
The fracture was easiest seen when compared with a radio-
graph of the opposite limb.
Treatment/Management: The fracture was treated only
through the use of a supportive wrapping.
Comments: The fracture had not been detected radiograph-
ically at the time of original injury and as a result the injury
was underdiagnosed as a traumatic arthrosis and undertreated.
The age and complete nature of the fracture was difficult to
determine on the study made four months after the suspected
injury; however, with fragment displacement the fracture was
complete and the indistinct appearance of the surface of the
fracture fragments indicated it was old (arrow).
Fractures in small bones do not produce callus as easily as do
long bones surrounded by a vascular soft tissue; thus, in this
case this could either be a non-union fracture or a fracture
healed with a fibrocartilaginous callus.
Forefoot 311
4

Case 4.27
4

Signalment/History: “George” was a 6-year-old, female
Irish Setter with a history of unknown injury to the right foot.
Physical examination: Palpation of the digits showed firm
soft tissue masses around the 2nd
and 5th
digits on the right foot.
feet.
Radiographic diagnosis: On the right foot, chronic intra-
articular fractures affected the distal interphalangeal joint of
the 2nd
digit and the same joint on the 5th
digit. The fragments
(white arrows) had a smooth border without any signs of ac-
tive repair processes. The fracture lines were indistinct, an in-
dication of chronic trauma. Periosteal new bone was especial-
ly prominent on the 2nd
digit. Soft tissue swelling was mini-
mal.
A similar pattern of chronic change was noted on the left foot,
though with much less severe change.
Differential diagnosis: Exclusion of infectious and neoplas-
tic lesions was the main differential problem. In this dog, the
features were rather specific for chronic trauma with the frac-
ture lines and fracture fragments being identified. The pe-
riosteal response was adjacent to the injured joint and did not
suggest either an inflammatory or neoplastic lesion.
Treatment/Management: Having found an injury due to
old trauma, the choice of treatment was limited. Amputation
could be considered if one of the lesions was causing a partic-
ular clinical problem for the dog.
Comments: Injury of this type is more likely in the 2nd
and
5th
digits.
Forefoot 313
4

Case 4.28
Signalment/History: “Beaver”, a 5-year-old, female
Labrador Retriever, had fallen 4 meters from a roof onto the
ground. Injury to both forefeet was evident. In addition, a
pneumothorax required immediate treatment.
Physical examination: Palpation of the feet produced
marked instability suggesting fracture/luxation. Dyspnea was
pronounced.
Radiographic procedure: Radiographs of the thorax and
the cranial portion of the thoracic spine were done at admis-
sion. The former were made because of the dyspnea and the
latter because of a suspected segmental instability noted on the
thoracic studies. After nine days in the clinic, the dog stabilized
and both feet were radiographed including stress radiographs.
Radiographic diagnosis (day 1, cranial thoracic spine):
A collapse of the T4–5 disc space with minimal malalignment
of the segments was note on both projections.
Radiographic diagnosis (day 9,feet): Fracture/luxation of
the carpometacarpal joints on the left caused extensive insta-
bility as evidenced by a palmar displacement of the head of the
2nd metacarpal bone. Also note the lateral displacement of the
metacarpal bones indicating the severity of the injury.
Fracture/luxation of the intercarpal joints on the right result-
ed in a palmar displacement of the distal row of carpal bones
and hyperextension. The fractures appeared to be limited to
small chip and avulsion fragments.
Treatment/Management: Pancarpal arthrodesis and partial
carpal arthrodesis were attempted.
Despite the collapse of the T4–5 disc space (arrow), the neu-
rologic examination was thought to be normal and conse-
quently, the spinal subluxation was not treated. The finding of
the spinal injury did indicate the requirement for cage rest for
a period of time after the trauma.
Outcome: Radiographs were made eight months following
the corrective surgeries, at which time both surgeries were
clinically and radiographically considered healed with the an-
ticipated arthrodeses.
Comments: The minimal periosteal new bone seen on the
distal aspect of the accessory carpal bones is compatible with
time being nine days post-trauma.
4
Day 1

Signalment/History: “O.J.” was a 7-week-old, female
Labrador Retriever puppy noticed by the owner to be lame on
the right forelimb.
Physical examination: Pain was not evident on examina-
tion; however, she was an excited, hyperactive puppy. She was
definitely lame when jumping around the examination room.
Radiographic procedure:A study was done of the right and
left forefoot
Radiographic diagnosis: Complete fractures of the proxi-
mal portions of the 2nd and 3rd metacarpal bones were noted
(arrows).
Treatment/Management: The fractures were treated by
splinting.
Outcome: The metacarpal fractures healed within two
weeks, which is within the expected time considering the ap-
parent low energy of the trauma and the young age of the pa-
tient.
Case 4.29
4

Case 4.30
Signalment/History: “Muffie” was a 7-year-old, female
Miniature Poodle who had been struck by a car and injured
her left forelimb.
Physical examination: Severe soft tissue injury character-
ized the open, comminuted fractures in the left foot.
tal left forelimb.
Radiographic diagnosis (day 1): The original radiographs
were made with the foot in a thin bandage and were diagnos-
tic of a severe “degloving” type of injury with the abrasion re-
moving a portion of the distal radius and ulna, part of the
carpal bones, and the proximal part of the metacarpal bones.
The injury is on the dorsal surface and all of the soft tissues on
the extensor surface are missing.
Differential diagnosis: Detection of bone infection cannot
be made at the time of an injury, but such an open lesion must
always be considered as being infected.
Treatment/Management: A second radiographic study was
made five weeks later following only treatment of the soft tis-
sue injury.
Radiographic diagnosis (week 5): At this time, the distal
ulna had become atrophic as characterized by “penciling”
(arrow). The remaining bones had less density, although the
study was made with the splint in position somewhat com-
promising the determination of bone density. It remained dif-
ficult to identify any changes typical of bone infection, but it
had to be assumed that it was present.
Treatment/Management: Carpal arthrodesis was per-
formed with good results fusing the radius, carpal bones, and
metacarpal bones.
Outcome: Unfortunately, a marked dorsal angulation plus
varus deformity resulted leaving the dog with a leg that could
be used for little more than a support.
Comments: Interestingly, infection was successfully con-
trolled by antibiotic therapy and did not interfere with the
arthrodesis.
Forefoot 317
4
Day 1
Week 5

Case 4.31
4

Signalment/History: “Kalu”, a 1-year-old, male Labrador
Retriever had suffered an acute lameness in the left forelimb
six weeks previously. The limb had been splinted for ten days.
Physical examination: Point tenderness over the proximal
sesamoid bones on the palmar surface of the 2nd
digit on the
left. Similar tenderness was noted in the same area of the 2nd
and 3rd
digits on the right
Radiographic procedure: Multiple views were made of
both forefeet.
Radiographic diagnosis: Multiple non-union fractures of
the proximal sesamoid bones on the plantar surface of the 2nd
and 3rd
digits on the right and the 2nd
and 5th
digits on the left
were to be seen (arrows).
Differential diagnosis: The differential diagnosis for lesions
of this type included three specific entities: (1) congenital bi-
partite sesamoid bones, (2) fractured sesamoid bones, and (3)
degenerative changes resulting in fragmentation and soft tissue
mineralization.
Treatment/Management: Because the clinical signs were
on the left, that foot was operated and the fragmented
sesamoid bones were removed from the 2nd and 5th digits.
Comments: The use of a plastic paddle to assist in position-
ing the foot resulted in a shadow of reduced tissue density
across the feet.
4.2.1.6 Pelvic limb injury
Pelvis
The os coxae, or the hipbone, is composed of the ilium, ischi-
um, pubis, and the acetabular bone. Fusion of these bones re-
sults in the creation of the os coxae including the acetabulum
that ultimately receives the femoral head. The two hipbones
join at the pelvic symphysis to form the pelvis. The pelvic
symphysis consists of the pubic symphysis and the ischial sym-
physis. The ischial symphysis contains a separate small triangu-
lar ossification center caudally. With age, the ischial symphysis
ossifies though in smaller dogs, the pubic symphysis often re-
mains cartilaginous. The pelvis attaches to the sacrum at the
sacroiliac joints. They are a combined synovial and cartilagi-
nous joint; the cranial portion of which is radiolucent because
of the presence of a fibrocartilage plate, whereas the caudal
portion often undergoes bony fusion with age. The pattern of
degeneration is breed/size dependent. Visualization of the
sacroiliac joint on the ventrodorsal radiographs is dependent
on the conformation of the iliac wings and often is not sym-
metrical as seen on radiographs made of a malpositioned pa-
tient.
Injuries of the pelvis are unique because of its anatomic struc-
ture (Table 4.5). The resulting pattern of injury to the bony
pelvis can be thought of as that expected with a disruption of
a “box” or “ring” in which one side has been fractured. To
permit the displacement of one fragment, additional fractures
must be present and three separate fractures are often identi-
fied as having occurred together. A common pattern of injury
involves ipsilateral fractures of the body of the ilium, the body
of the pubis, and the ischiatic table. This effectively frees a seg-
ment of the pelvis containing a hip joint. Another common
pattern involves fractures of the body of the ilium on one side,
the body of the opposite pubis, and the opposite ischiatic table.
This also frees a segment of the pelvis including a hip joint.
Often fractures affect the pelvic symphysis and these cannot be
identified either on lateral radiographs due to a lack of frag-
ment displacement or on the VD radiograph because of su-
perimposed coccygeal segments and a rectum filled with fecal
material. These are referred to as fractures in the “floor of the
pelvis”.
Injury to the sacroiliac joints is somewhat dependent on age,
since the caudal portion of the joints ossifies with age and the
joints become stronger. In the younger patient, the joints can
luxate rather easily often resulting in luxation of one sacroiliac
joint plus ipsilateral fractures in the pubis and ischium. A com-
mon injury in the cat is the luxation of both sacroiliac joints as
the only injury freeing the bony pelvis to shift cranially, the
result of pulling by the rectus abdominis muscles. Any injury
to the sacroiliac joints should prompt a careful search for a frac-
ture line that enters the sacrum; this is more commonly found
in the older patient because of the bony fusion of the joints.
Careful inspection of the acetabulum and femoral head is im-
portant, since fractures that enter the hip joint affecting the ar-
ticular surface have great clinical importance because if the
Pelvis 319
4

fracture is not anatomically reduced, a post-traumatic arthro-
sis will develop. The fracture may only affect the margin of the
acetabulum or may pass through the hipbone, or the fracture
may involve the opposite articular surface with fragmentation
of the femoral head.
Avulsion fractures in the pelvis can occur in the immature pa-
tient resulting in a separation of the centers of ossification in
the ilial crest and in the ischiatic tuberosity. Because these frac-
tures do not affect weightbearing bones and are not articular,
they are not usually treated, though they are a source of pain.
Injuries to the tail can be assessed on the radiographs of the
pelvis, though they are best seen on the lateral view, since the
rectal contents often prevent the detection of fracture/luxa-
tions near the sacrococcygeal junction. The nature of the frac-
ture uncommonly tells of the severity of the injury to the cau-
da equina contained within the segments.
Injury to the lumbosacral junction has a particular importance
and is discussed with lesions of the lumbar spine (Chap.
4.2.2.3).
Table 4.5: Radiographic signs of pelvic trauma
1. pattern of fractures or luxations because of a “box” or “ring”
configuration (Cases 4.34, 4.35, 4.36, 4.37 & 4.41)
a. ilium, pubis, and ischium on the same side
b. ilium on the one side, and pubis and ischium on the opposite side
c. pelvic symphysis plus other fractures (Case 4.27)
d. both sacroiliac joints with cranial displacement of the bony pelvis
(Case 4.45)
e. sacroiliac joint, pubis and ischium on the same side (Cases 4.32, 4.63 &
4.128)
f. sacroiliac separation (Cases 4.195 & 4.107)
g. sacroiliac joint on the one side, and pubis and ischium on the opposite
side (Case 4.41)
2. avulsion of the ilial crest or ischial tuberosity (Cases 4.42, 4.106 & 4.132)
3. sacrococcygeal fracture/luxation (Case 4.38)
4. coccygeal fracture/luxation (Case 4.56)
5. unique patterns
a. fracture pattern leading to a narrowing of the pelvic canal
(Cases 4.33, 4.56, 4.99, 4.103, 4.102 & 4.112)
b. pelvic injury including an acetabular fracture (Cases 4.34, 4.36, 4.37,
4.40 & 4.107)
c. pelvic injury including a sacral fracture (Cases 4.39, 4.49 & 4.93)
6. patterns of soft tissue injury
a. intrapelvic hemorrhage
b. rupture of the urethra or bladder neck (Case 4.33)
c. change in position of the feces- or air-filled rectum (Cases 4.108
& 4.112)
d. failure to identify the prostate gland because of hemorrhage or urine
(Case 4.104)
e. failure to identify the urinary bladder because of rupture
f. subcutaneous emphysema (Case 4.62)
g. peritoneal fluid
h. displaced urinary bladder (Case 4.108)
i. rectal diverticulum (Case 4.108)
4

Case 4.32
Signalment/History: “Dog” was a 2-year-old, female
mixed breed that had jumped from the back of a moving truck
and was unable to walk normally after the accident.
Physical examination: She would not bear weight on the
left pelvic limb in the examination room. Palpation of the
pelvic region produced pain especially when moving the left
pelvic limb. Crepitus was not detected.
Differential diagnosis: A pelvic fracture was suspected.
Radiographic procedure: Both VD and lateral views were
made.
Radiographic diagnosis: Fractures of the left hemipelvis in-
volved the pubis (black arrow) and ischium, and were located
just caudal and medial to the acetabulum. The comminuted
fracture entered the caudal aspect of the acetabular roof as
viewed on the lateral projection (white arrow) with a single
bony fragment being identified. Displacement of the fracture
fragments caused only minimal narrowing of the pelvic canal.
Treatment/Management: Because of the slight displace-
ment of fragments and involvement of the caudal, non-
weight-bearing portion of the acetabular roof, “Dog” was
successfully treated with cage rest.
Outcome: Fracture healing in a young dog occurs quickly
and he was exercising normally within 3 weeks.
Comments: It appeared as though the rule of “three pelvic
fractures” was broken in this case. The third site of trauma ap-
parently was the undetected injury to the left sacroiliac joint
that provided the movement necessary to free the hemipelvis.
Often sacroiliac injury is extensive; however, in this patient,
the injury was minimal and without displacement.
The flexed view for the pelvis was used in this case because it
was much less painful to position the pelvic limbs in flexion
than attempting to extend what may have been a limb with a
fractured femur or move bony fragments associated with an
injured hip joint.
Note how the left-sided fractures resulted in a medial dis-
placement of the left hemipelvis and a collapse resulting in the
obturator foramen appearing smaller on the radiograph.
Pelvis 321
4

Case 4.33
4
Noncontrast

Signalment/History: “Scardy Cat”, a 4-month-old female
kitten, had been run over by the owner’s car.
Physical examination: The cat was lame and could not walk
on the left pelvic limb. Her abdomen was enlarged and the
bowel loops palpated to be distended with fluid contents, i.e.
the bowel felt fluid-filled.
Radiographic procedure: The radiographic study included
both the abdomen and pelvis.
Radiographic diagnosis (abdomen and pelvis): The ab-
domen was fluid-filled with two gas-filled small bowel loops
floating in the peritoneal fluid. The abdominal organs could
not be identified. Pelvic injuries were generalized and includ-
ed a right-sided sacroiliac separation, a left ilial fracture, and
narrowing of the pelvic inlet. Left pubic and ischial fractures
were not visualized, but were required to permit the medial
displacement of the left hemipelvis. The fractures on the left
side seemed to be just cranial to the acetabulum; however, this
was difficult to evaluate.
Treatment/Management: As the use of a retrograde ure-
throgram/cystogram is indicated to determine the status of the
urinary bladder in a patient with pelvic injuries, where there
is an inability to identify the urinary bladder on an abdominal
radiographic study, this procedure was done in “Scardy cat”.
Radiographic diagnosis (retrograde urethrogram): Pos-
itive contrast was injected through a urethral catheter and re-
sulted in a peritoneal flow of the agent indicative of a urethral
or bladder neck rupture. The contrast agent against the seros-
al surface (black arrows) outlined the size, shape, and position
of the urinary bladder.
Outcome: The patient was euthanized because of the pro-
jected expense of treating the injuries.
Pelvis 323
4

Case 4.34
Signalment/History: “Augie” was an 8-month-old, female
Doberman Pinscher who had fallen down a steep incline while
hiking with her owner. She has been hesitant to walk since
that time.
Physical examination: The dog was lame when examined
and non-weightbearing on both pelvic limbs at the time of ex-
amination. Crepitus was palpated with movement of the left
hip joint. Pain was elicited on rectal examination especially on
the left side.
pelvis.
Radiographic diagnosis: Multiple fractures of the left
hemipelvis involved the ileum, ischium and pubis. The ace-
tabula appeared to be unaffected (day 1).
Note how the ileal fracture is compacted and that the fracture
line is difficult to identify radiographically (white arrow)
Treatment/Management: Because the hip joints appeared
intact, the fracture was not treated surgically and the owner
was instructed to severely limit the patient’s physical activity.
Additional radiographs were made 11 days later and showed
inward displacement of the left ileum and ischium opening the
previously undetected acetabular fracture. A third study was
made 50 days after the injury and showed a massive callus
forming around the fracture sites. At that time the dog was
showing no pain or lameness.
Comments: The rather good fragment positioning present at
the time of the injury was lost by permitting the dog freedom
to exercise. The lesion involved the acetabular cup more than
was thought originally and a secondary arthrosis will be a se-
quela in this patient. The exuberant callus that formed around
the acetabular fractures almost had a malignant appearance be-
cause of the rapid development of new bone in a skeletally
young puppy.
4 Day 1 Day 11

Signalment/History: “Bridgette” was a 2-year-old, female
Labrador Retriever who had a history of falling from a truck
two months previously and had had pain in the pelvic region
since that time.
Physical examination: The dog was not painful on palpa-
tion, although she was somewhat tense from being in the clin-
ic thus making examination difficult. Soft tissue atrophy was
prominent around the left pelvic limb.
Radiographic procedure: Studies were made of the pelvis
because of the clinical history.
Radiographic diagnosis: Healing fractures were noted in
the left acetabular branch of the pubis, body of the left ischi-
um, and left symphyseal branch of the ischium (arrow). Soft
tissue atrophy in the muscles of the hind limbs was noted. The
fractures involved the ischium just caudal to the left acetabu-
lum, but did not seem to have actually entered the articular
surfaces. The femoral head was slightly luxated, perhaps af-
fected by the adjacent soft tissue atrophy or influenced by a
pre-existing hip dysplasia.
The shape of the pelvis was not altered suggesting that the
fractures were essentially without fragment displacement. This
partially explained why the owners were late in bringing
“Bridgette” for treatment.
Case 4.35
Treatment/Management: A cautious prognosis was offered
because of a questionable status of the hip joint. The owner
was encouraged to use physiotherapy in an effort to help the
dog to regain use of the left hindleg. The dog was discharged
without a definitive treatment plan because of the partial heal-
ing of the fractures, but the owner was optimistic about the
possibility of the dog being a happy pet.
Pelvis 325
4

Case 4.36
Signalment/History: “Ben” was a 14-month-old, male
Great Dane who had probably been struck by a car approxi-
mately two weeks earlier. The owners finally brought him
into the clinic because he “does not walk right”. They also said
he had not urinated since the accident.
cause of the dog’s size, but crepitation was noted in the pelvic
region more prominently on the left side. Rectal palpation was
incomplete but no abnormalities were noted. No neurologic
deficits were noted, except for the dog’s unwillingness to use
the pelvic limbs.
pelvis. The lateral view was directed at the abdomen because
of the question of the status of the urinary bladder and was un-
derexposed for a study of the pelvis.
Radiographic diagnosis (pelvis): Multiple pelvic fractures
involved the right acetabulum, left ilium, the left acetabular
branch of the pubis, the left ischiatic table, and an avulsion
fragment from the left tuber ischii (arrow). The pubic symph-
ysis was partially separated. The fragments were noted to
move freely on comparison of the two VD views. A soft tissue
mass was noted beneath the sacrum that probably represented
a hematoma.
Treatment/Management: A greater trochanter osteotomy
was performed to gain access to repair the right acetabular
fracture using a five-hole bone plate held in position by five
cortical screws. “Ben” was discharged 12 days post trauma and
could walk, but he still showed signs of pain.
Comments: Studies of a giant breed are always compromised
by the size of the dog.
4

Case 4.37
man Shepherd who had escaped from the yard and was absent
for seven days. He had returned the evening before not able to
bear weight on the left pelvic limb.
Physical examination: Crepitus was noted on palpation of
the pelvis.
Radiographic procedure: Routine views were made of the
pelvis.
Radiographic diagnosis: The fracture fragments in the left
ischium were displaced and the fracture line angled caudo-
ventrally. The femoral head was driven medially and impact-
ed between the ilial fragment laterally and the ischial fragment
medially. Fractures of the left pubis and ischium permitted
complete separation of the caudal fragment on the left.
The right coxofemoral joint and iliosacral joints were normal
in appearance.
Treatment/Management: An injury of this type requires
surgical treatment to free the femoral head and restore some
degree of joint architecture Because of the age of the fracture
that suggested possible immobility of fragments due to early
healing, the unwillingness of the owner to consider the cost of
surgical treatment, and the presence of sacral canal stenosis,
euthanasia was carried out.
Comments: Sacral canal stenosis assumes importance as a dog
ages and can be one of the features causing a cauda equina syn-
drome and its presence complicated the prognosis in this dog.
Sacral canal stenosis is a commonly inherited trait in this
breed.
Pelvis 327
4

Case 4.38
Signalment/History: “Sam” was a 3-year-old, male Dachs-
hund admitted with the sudden onset, two days previously, of
urinary incontinence, pelvic limb ataxia, and straining at defe-
cation.
Physical examination: He was ambulatory with probable
decreased conscious proprioception in the right pelvic limb.
The anus was flaccid. Crepitus could be detected on palpation
of the pelvic limbs. Because of the breed, a disc protrusion was
strongly considered.
Radiographic procedure: The spine and pelvis were radio-
graphed.
Radiographic diagnosis: The presence of a sacrum with
four segments made localization of the acute fracture/luxation
confusing. The injury was centered at the junction of the 2nd
and 3rd
sacral segments with some displacement of the frag-
ments. A free cortical fragment was located ventrally. The uri-
nary bladder was distended.
Differential diagnosis: The injury site appears to be defined
by a lucent zone in the sacrum with a slight collapse charac-
terized by a dorsocranial displacement of the caudal segments.
The lesion appeared to be more a pathologic fracture due to
the folding and bending of the cortical bone (arrow). A patho-
logic fracture could involve either a benign or malignant bone
lesion. The absence of recognized trauma supported a diagno-
sis of this type rather than one of pure trauma. Neurologic
signs of a cauda equina syndrome may always be due to lesions
such as a degenerated lumbosacral disc with dorsal protrusion
and not due to the trauma, or both can play a role in the syn-
drome.
Treatment/Management: The owners chose to have the
patient treated conservatively. The dog was discharged in a
more comfortable state and was able to walk, but was lost to
follow-up.
Comments: This patient is an example of neurologic deficits
causing a cauda equina syndrome in a breed frequently affect-
ed by disc disease that has instead, radiographic evidence of
atraumatic or pathologic fracture. This patient should have
been followed radiographically to ascertain the exact nature of
the fracture. A biopsy should have been taken to ascertain the
nature of the abnormal tissue.
4

Case 4.39
Signalment/History: “Sophie” was a 1-year-old, female cat
who was presented with incoordination in her pelvic limbs.
The owners assumed trauma as the etiology.
Physical examination: The spinal reflexes were normal.
Pain perception was present in the hindlimbs and tail. The hip
joints palpated normally. No crepitus was evident.
Radiographic procedure: Ventrodorsal and lateral views
were made of the pelvic region.
Radiographic diagnosis: Pubic, ischial and sacral fractures
(arrows) permitted cranial displacement of the right hemi-
pelvis. The sacral fracture entered the lumbosacral disc space
with destruction of its lateral component. The hip joints were
radiographically normal. The urinary bladder was seen to be
normal in size, shape, and position.
Treatment/Management: The owners chose euthanasia.
Comments: The traumatic injury involved the sacrum and
LS disc in a manner that is unusual for pelvic trauma.
Pelvis 329
4

Case 4.40
Signalment/History: “Wally” was a 2-year-old, male
Spaniel who had jumped from a truck three days previously.
He had been unable to walk normally after the accident and
was treated at an emergency clinic and then referred.
Physical examination: Pain was evident on palpation of the
right pelvic limb especially on movement of the hip joint.
pelvis.
Radiographic diagnosis: An unusual pattern of fracture
lines involved the right ilium and then extended caudally over
the acetabular roof into the ischium. Minimal displacement of
the fragments was evident. The fracture lines definitely en-
tered the acetabulum and resulted in subluxation of an other-
wise normal femoral head.
Treatment/Management: A contoured reconstruction
plate was used to repair the ilial and ischial fractures. “Wally”
was discharged to the referring clinician and was lost to follow-
up.
4

Case 4.41
Signalment/History: “Buster” was a 3-year-old, male cat
who had been involved in a car accident one day before pres-
entation.
Physical examination: Palpation of the pelvis suggested
multiple pelvic fractures. The hip joints palpated normally;
however, crepitus was noted on more aggressive movement of
the pelvic limbs.
Radiographic procedure: Radiographs of the pelvis were
made.
Radiographic diagnosis: A right sacroiliac separation
(white arrow), left ilial fracture with overriding of the frag-
ments (black arrows), left pubic fracture, and left ischial frac-
ture permitted cranial displacement of the pelvis. Both hip
joints appeared normal. The sacrum was unaffected.
Treatment/Management: Because of the lack of injury to
the hip joints and the absence of collapse of the pelvic canal,
“Buster” was treated with cage confinement for two weeks
with the hope that the fractures would heal without malalign-
ment.
Comments: Pubic and ischial fractures near the symphysis
pubis are difficult to identify on either lateral or VD projec-
tions. Often the incomplete evaluation radiographically is ac-
cepted because surgical treatment of the fractures is not usual-
ly considered.
Pelvis 331
4

Case 4.42
Signalment/History: “Corky” was a 9-month-old, male
mixed-breed dog who was presented with an acute onset of
left pelvic limb lameness. The owners knew of no injury, but
admitted that the dog was free to run in the garden and onto
the adjacent highway.
Physical examination: Palpation of the pelvic region pro-
duced severe pain on the left side.
Radiographic procedure: Studies were made of the pelvis.
Radiographic diagnosis: A fracture of the ischium with
fragment separation was noted (arrow). The hip joints were
not affected.
Comments: This is a somewhat unique type of ischial frac-
ture with the trauma apparently directed from behind the dog.
Note the open growth regions on the dorsum of the femoral
neck where the lip of bone from the greater trochanter has yet
to unite with the lip of bone that will grow down from the
femoral head.
4

Case 4.43
Signalment/History: “Black Boy” was a 7-year-old, male
German Shepherd with pain noted in the pelvic region after
exercise. The owners did not know anything about the dura-
tion of the pain.
Physical examination: The dog was definitely limping on
the left pelvic limb; otherwise, the physical examination con-
tributed little information.
and pelvic limbs.
Radiographic diagnosis:Dorsocranial bilateral coxofemoral
luxations appeared chronic with acetabular modeling and val-
gus deformity of the modeled femoral heads and necks. Disuse
osteopenia in the femoral heads indicated that disuse of the
limbs was chronic and present for a period of time.
Comments: It was remarkable that the bilateral coxofemoral
luxation was not noted on the physical examination, especial-
ly considering the marked muscle atrophy and the probability
of bilateral patellar luxation.
The differential diagnosis of chronic hip lesions should include
the following possibilities: (1) bilateral congenital hip luxation
with marked valgus deformity of the femoral necks, (2) bilat-
eral hip luxation associated with hip dysplasia, and (3) bilater-
al traumatic luxation of the femoral heads. All could have been
present when the dog was young and determination of the
etiology was now clouded by the extensive secondary model-
ing that had occurred.
If the owner does not know the patient well, it is difficult to
obtain a meaningful history relative to past lameness or pain.
Often the clinical and radiographic examination in such cases
provides the cause of the pain/lameness, but not their etiolo-
gy.
Pelvis 333
4

Case 4.44
4

Signalment/History:“Ginger” was a 13-month-old, female
Labrador Retriever who had been struck by a car that morn-
ing.
Physical examination: The patient was difficult to exam-
ine, but it was obvious that she had a stilted, guarded gait in
the pelvic limbs.
pelvis.
Radiographic diagnosis: The floor of the pelvis was frac-
tured free at the junction of the pubis and ilium on both sides
and at the junction of the pubis with the ischium. A probable
separation of the left sacroiliac joint was noted. Severe arthro-
sis of both hip joints secondary to hip dysplasia was also pres-
ent. A congenital sacral spinal canal stenosis was detected
(black line).
Comments: Frequently, larger dogs who have hip joint dis-
ease from dysplasia also sustain pelvic trauma and it is neces-
sary to determine whether the presenting clinical signs are the
result of injury to the joints with a resulting chronic arthrosis
or are the result of an acute bone or joint injury. The presence
of the arthrosis obviously complicates ambulation of the pa-
tient during the healing stage of the fractures. This factor
needs to be explained to the owner. Also, the owner needs to
understand that subsequent pain and lameness in the pelvic
limbs is probably due to the arthrosis and not due to a problem
in the treatment of the fractures.
The congenital canal stenosis has an important clinical signif-
icance since it can be associated with the development of a
cauda equina syndrome. Again, this is not a problem associated
with treatment of the fractures
Pelvis 335
4

Case 4.45
Signalment/History: “Puss” was an 11-month-old, female
kitten who had been struck by an automobile several hours
previously.
Physical examination: She was dyspneic with open-mouth
breathing, and in shock. Examination was limited but it was
obvious that the kitten could not bear continual weight on the
right pelvic limb, although she could stand briefly. Crepitus
was palpated over the right hip joint.
Radiographic procedure: Both thoracic and pelvic radio-
graphs were made.
Radiographic diagnosis (thorax): Subcutaneous emphyse-
ma was identified on the right extending into the cervical re-
gion. Consolidation was noted of both lung lobes on the left.
Pulmonary edema/hemorrhage was present in the right cra-
nial lung lobe. A minimal pneumothorax was present. This
was best seen where the free air contrasted with the partially
atelectic lung lobes in the left hemithorax. No pleural fluid
was seen. The cardiac silhouette was on the midline but not
clearly identified because of the pulmonary fluid.
4

Radiographic diagnosis (pelvis): Bilateral sacro-iliac luxa-
tions caused cranial displacement of the bony pelvis. Pubic and
ischiatic symphyseal fractures resulted in collapse of the pelvic
canal caudally. A sacral fracture resulted in malalignment of
the vertebral segments. Both hip joints were normal in ap-
pearance.
Treatment/Management: “Puss” unfortunately had no
owner and was euthanized.
Pelvis 337
4

Case 4.46
Signalment/History: “Partner” was a 5-month-old, male
Golden Retriever puppy who had been hit by a car five days
previously and had remained lame after the injury.
Physical examination: The examination was difficult to
perform because of the age of the puppy and the lameness on
the left side.
Radiographic diagnosis: Fracture lines entered the left ace-
tabulum resulting in some displacement of the fragments. A
second fracture line was just caudal to the right acetabula. A
pubic and ischial fracture resulted in a free segment from the
floor of the pelvis. Of greater importance was the slippage of
the capital epiphysis on the left (arrow).
Outcome: The owner refused to pay for treatment of the
fractures and the patient was subsequently released. The frac-
tures will all probably undergo malunion because of the young
age of the patient. Unfortunately, the injury to the acetabulum
will result in a post-traumatic arthrosis later in life. The heal-
ing of the slipped capital epiphysis is more problematic with
the possibility of aseptic necrosis of the capital epiphysis lead-
ing to rather severe joint disease
4

Case 4.47
Signalment/History: A male Husky mixed breed was pre-
sented having been found by the roadside by a person who
witnessed a car striking the dog. The dog was then kept at the
new home for five days awaiting its original owner to claim it.
After this period of time, the dog was presented by the new
owner for treatment because of the persistent lameness of the
right pelvic limb.
Physical examination: Pain was identified within the pelvic
region, especially on palpation of the right hip joint. Crepitus
was noted in that hip joint.
Radiographic diagnosis: Multiple pelvic fractures were
identified with only minimal displacement of the fragments,
as seen on the ventrodorsal view, but with marked ventral an-
gulation of the ischial fragment as seen on the lateral view (ar-
row). The most important injury involved the right acetabu-
lum; however, the important dorsocranial weight-bearing
portion of the articular surface appeared not to be trauma-
tized. Prepubic and ischiac fractures were identified (small
arrows). The urinary bladder was distended and easily visual-
ized. The prostate gland was enlarged.
Treatment/Management: Treatment was not considered
because of failure to locate the original owner of the dog.
Pelvis 339
4

Hip Joint
The hip joint is a most important component of the pelvic
limb and is often subjected to trauma. Radiography of the
hips in the traumatized patient often requires positioning the
patient in a VD view with the hindlimbs extended and this
view may be very painful. It is much less traumatic to place the
hindlimbs equally into a fully flexed position.
Luxations are the most common injury and the injury site
needs to be carefully examined for avulsion fractures from the
femoral head, fractures that split the femoral head, and frac-
tures from the acetabular margin. All of these reduce the
chance of a successful reduction of a luxated femoral head.
Closed reduction of the femoral head in a joint affected by hip
dysplasia is not often successful and the influence of the
arthrosis needs to be recognized (Table 4.6).
In the immature patient, slippage of the capital epiphysis re-
sults in a loss of blood supply to the femoral head because of
the intracapsular location of the physis. A subsequent necrosis
of the femoral head will occur unless the reduction and fixa-
tion is immediate and anatomically successful. With a coxo-
femoral luxation, a tearing of the ligament of the femoral head
may result in an avulsion fracture from the fovea of the femoral
head or a fracture from the margin of the acetabulum. In an
older patient with more severe trauma, a splitting of the
femoral head can occur (Chap. Femur). The particular impor-
tance of physeal fractures that separate the capital epiphysis is
also discussed in the section about the femur.
In larger dogs, the high frequency of arthrosis secondary to hip
dysplasia often complicates the interpretation of the clinical
signs of a traumatic injury. It also may complicate the inter-
pretation of radiographs in such cases, where acute fractures
can be masked by the reactive changes seen in a joint with
chronic arthrosis. This is also true of older patients with
chronic arthrosis associated with hip dysplasia. In suppurative
arthritis, the destructive changes often cannot be identified
because of the superimposed reactive new bone associated
with the dysplasia.
Clinical signs thought to be due to injury to a hip joint may
instead be actually associated with lumbosacral disease or stifle
joint disease. A dog that shows pain when pressure is placed on
its back may be telling you about the LS joint or stifle joint in-
stead of the hip joint. For this reason, radiographic evaluation
of the LS region and stifle joint may be as important as evalu-
ation of the hip joint itself.
Table 4.6: Radiographic signs of trauma to the hip joint
1. Pattern of coxo-femoral luxation
a. displacement of the femoral head is usually dorsal and cranial
(Cases 4.50, 4.52, 4.53, 4.54, 4.57, 4.60, 4.61, 4.103 & 4.130)
b. examine for associated fracture (Cases 4.60 & 4.73)
c. examine for preexisting arthrosis (Case 4.67)
d. chronic luxation (Cases 4.48, 4.50 & 4.57)
2. Pattern of acetabular fracture (Cases 4.32, 4.33, 4.34, 4.36, 4.40, 4.46,
4.47, 4.49, 4.69 & 4.99)
a. often the detection of a fracture line into the acetabulum is difficult
b. fracture lines often enter dorsocaudally and are not as clinically
important
c. pattern is often comminuted
d. oblique or flexed limb studies often contribute to a full understanding
of the fracture
e. post trauma (Cases 4.61, 4.102, 4.103, 4.105 & 4.127)
3. Pattern of superimposed infection (Case 4.55)
a. destructive lesions are present in the subchondral bone
b. articular surfaces are roughened
c. periosteal new bone is indistinct and superimposed over old
osteophytes
4. Pattern of soft tissue injury
a. examine for atrophy to indicate chronicity (Cases 4.32, 4.35, 4.43, 4.48,
4.57, 4.58, 4.61, 4.99 & 4.104)
b. gunshot pattern may be present and is often not clinically important
5. Post-operative patterns (Case 4.58)
6. Post-operative arthrosis (Case 4.107)
4

Case 4.48
Signalment/History: “Harlow” was a 1-year-old, female
Dalmatian who had been hit by a car and given emergency
treatment for thoracic wall injury, mediastinal hemorrhage,
pulmonary contusion, pleural hemorrhage, and minimal
pneumothorax. She rapidly developed signs of severe abdom-
inal blood loss and at surgery a torn uterine artery was ligated.
Several days after the trauma, she was reluctant to use her right
pelvic limb and on presentation, crepitus was palpated in a
painful hip joint.
Physical examination: Examinations during hospitalization
were difficult because of the original trauma and then because
of the post-surgical status of the dog. Eventually it was possi-
ble to palpate the hip joints and a luxation was noted on the
right side.
Radiographic procedure: Views were made of the pelvis.
Radiographic diagnosis (day 3 post presentation): A
craniodorsal coxofemoral luxation was noted on the right with
an avulsion fracture fragment that originated from the right
femoral head.
Radiographic diagnosis (day 45 post presentation): A
persistent, craniodorsal coxofemoral luxation was seen on the
right with modeling of the bony fragments within the aceta-
bulum (arrows). New bone had formed on the ilium at the site
of pseudoarthrosis formation. Loss of bone density and loss of
muscle mass were both indicative of disuse atrophy.
Comments: The extensive thoracic and abdominal injury
was recognized and treated immediately following the trauma,
while diagnosis and treatment of the luxated hip had been de-
layed. “Harlow” is an example of a patient with multiple trau-
ma causing injuries to the thorax, abdomen, and a hip joint.
The satisfactory treatment of the acute problems was remark-
able, but failure to treat the hip joint injury more aggressively
left “Harlow” with the likelihood of a chronic post-traumatic
arthrosis in the right hip joint.
Hip joint 341
4
Day 3
Day 45

Case 4.49
Signalment/History: “Jenny”, a 7-month-old, female
Pointer, had been struck by a car and was lame on the right
pelvic limb.
Physical examination: Palpation suggested luxation of the
right femoral head. Additional injury was not detected.
Radiographic procedure: Two views of the pelvis were
made.
Radiographic diagnosis (day 1): A dorsocranial luxation of
the right femoral head left bony fragments that were either
chip fractures from the acetabular margin or avulsion fractures
from the fovea capitus.
Treatment/Management: Closed reduction was attempted
utilizing a DeVita pin to stabilize the femoral head. Addition-
al radiographs of the pelvis made one month later.
4
Day 1

Radiographic diagnosis (month 1): These showed bony
resorption within the femoral neck suggesting that a subcapi-
tal fracture had been present originally and had not been de-
tected, perhaps because of the more obvious luxation. The pe-
riosteal response on the ilium was probably due to placement
of the DeVita pin (arrows).
Comments: A review of the original radiographs suggested
an oblique radiolucent line across the femoral neck on the VD
view (white arrows) and a widened physeal plate as seen on the
lateral view (black arrows). These findings suggested the pos-
sibility of an intracapsular femoral neck fracture that lead to
the femoral neck resorption seen on the later radiograph.
The detection of fracture fragments within the acetabulum is
an indication for open reduction.
Hip joint 343
4
Month 1

Case 4.50
4

man Shepherd with a history of recent trauma (probably hit
by a car).
Physical examination: The dog was in pain and lame in the
right hip.
made.
Radiographic diagnosis: A chronic right femoral head lux-
ation was noted with a pseudoarthrosis formed dorsal to the
acetabulum.
The position of the right femoral head was dorsal to the ac-
etabulum on the lateral view (arrows). All of the bony pro-
duction noted around the right acetabulum on the VD view
was dorsal to the acetabulum.
Comments: The location of the lesion in “Duke” was
unique in that the pseudoarthrosis was directly dorsal to the
hip joint instead of its usual location cranial to the acetabulum
against the shaft of the ilium. Upon questioning, the owner
admitted that the dog had been acutely non-weight-bearing
on the right pelvic limb several weeks previously.
Hip joint 345
4

Case 4.51
Signalment/History: “Tiger” was an 8-year-old, male Ger-
man Shepherd with a low-grade, chronic, progressive lame-
ness in the pelvic limbs for the past several years. The owner
had seen the dog fall some days previously and noted that he
had become acutely lame.
Physical examination: Lameness of the pelvic limbs ap-
peared to be bilateral. Some loss of proprioception was detect-
ed on neurological examination.
Radiographic procedure: A VD view of the pelvis with the
limbs extended was made.
Radiographic diagnosis: Bilateral arthrosis was noted in
both hip joints and was characterized by joint laxity and sec-
ondary modeling. This was thought secondary to hip dyspla-
sia. The lumbosacral morphology was normal except for mod-
erate spondylosis deformans. The heavy enthesophyte forma-
tion on the iliac crests and ischial arch was thought to be due
to the age and size of the dog.
Comments: In the older patient, the pain associated with a
chronic arthrosis such as commonly seen in a dog with hip
dysplasia can become acute following minor trauma. As in
“Tiger”, this could have resulted in a marked change in the
clinical signs suggesting an acute injury rather than being as-
sociated with the chronic disease that was present in the hips.
Also, it is possible for an infectious arthritis to be superimposed
over the noninflammatory joint disease, such as would be
found in a patient with chronic arthrosis secondary to hip dys-
plasia. An infection would also cause a similar abrupt change in
pattern of the clinical signs. One of the purposes of radio-
graphic examination in this patient was to rule-out an infec-
tious process.
“Tiger” had neurological signs of a cauda equina syndrome
and, in conjunction with the minimal radiographic findings of
lumbosacral spondylosis deformans, indicated a requirement
for continued clinical evaluation. The progression of the neu-
rological signs would suggest the possible need for decompres-
sive surgery with or without stabilization of the lumbosacral
junction.
4

Case 4.52
Signalment/History: “Suma”, an 8-year-old, male German
Shepherd mixed breed, was lame on the right pelvic limb. No
history of trauma was available.
Physical examination: The right femoral head was luxated.
pelvis.
Radiographic diagnosis: The right femoral head was luxat-
ed in a cranial direction, although the right acetabulum ap-
peared unaffected. The femoral head on the left remained
within the acetabulum; however, an arthrosis secondary to hip
dysplasia was characterized by a prominent thickening of the
femoral neck.
The lumbosacral region was characterized by roughening of
the endplates of the L7 segment and the sacrum. Marked os-
teophyte formation bridged the lumbosacral disc ventrally.
Differential diagnosis: The hip luxation was assumed to
have been induced by trauma; however, it was not possible to
determine if an arthrosis secondary to hip dysplasia might not
have resulted in joint instability that could have played a role
in permitting the luxation. The lumbosacral lesion was
thought to be secondary to a chronic discospondylitis, a sacral
osteochrondrosis, or the result of a severely degenerated LS
disc. All of these would result in instability with formation of
the peripheral spondylosis deformans.
Treatment/Management: The femoral head was reduced
by closed reduction. The lumbosacral lesion was not treated at
this time because of the absence of signs of a cauda equina syn-
drome; however, the owner was advised to be observant.
Comments: In the event of future examination of the lum-
bosacral disc, it would be difficult to perform a discogram in
this dog because of the collapse of the disc space. An extradural
contrast examination would be possible to evaluate the pres-
ence of a mass lesion within the spinal canal. These examina-
tions were delayed awaiting the potential onset of neurologic
signs. The dog was not returned for follow-up examination.
Hip joint 347
4

Signalment/History: “Buffy” was a 1-year-old, female
mixed breed, who had been hit by a car two days previously
and had pain on the left pelvic limb.
Physical examination: On palpation, the left femoral head
was thought to be luxated dorsally. Soft tissue swelling was
noted in the left pelvic limb.
Radiographic diagnosis (day 2): A dorsocranial left coxo-
femoral head luxation was identified. A transitional sacrococ-
cygeal vertebra was present as an incidental finding.
Comments: The preservation of bone density and lack of any
responsive new bone suggest an acute injury. The absence of
a fracture fragment within the acetabulum improves the prog-
nosis for a successful closed reduction.
Radiographic diagnosis (year 6): Radiographic examina-
tion of the pelvis six years later revealed only minimal bony
changes suggesting minimal secondary post-traumatic arthro-
sis within the left coxofemoral joint.
Case 4.53
4 Day 2
Year 6

Case 4.54
Signalment/History: “Africa” was an adult, male Belgium
Sheepdog who had been hit by a car nine days previously. The
treating clinician had been unsuccessful in an attempt to re-
duce a suspected femoral head luxation.
Physical examination: Palpation of the right hip joint was
more painful than expected and the possibility of injury addi-
tional to a femoral head luxation was considered.
Radiographic diagnosis: A dorsocranial luxation of the
right femoral head was noted with comminuted fractures of
the right ileum that extended into the dorsocranial aspect of
the acetabular margin. An additional fracture extended
obliquely through the sacrum dividing it into two major frag-
ments (black arrow) and which resulted in a ventral angulation
of the distal fragment (black lines). The lumbosacral disc space
was wedge-shaped and suggested injury to the disc. Another
simple fracture extended into the right ischium (white arrow).
Bilateral arthrosis was characterized by thickened femoral
necks and shallow acetabula, and was thought to be secondary
to hip dysplasia.
Both stifle joints appeared normal.
Treatment/Management:The patient was treated in a con-
servative manner. The luxation was not reduced even though
the owner understood that a pseudoarthrosis would form. The
potential importance of the sacral fracture was not recognized
at the time of treatment. Any neurological signs present when
the dog was presented were masked by the painful character of
the injury to the hip joint. The owner was advised upon dis-
charge to observe the dog during convalescence for any signs
of persistent pain or failure to develop a more normal gait, ei-
ther of which could suggest the potential development of a
cauda equina syndrome.
Hip joint 349
4

4

Case 4.55
Signalment/History: “Black Jack” was a 5-year-old, male
Siberian Husky with a sudden onset of lameness on the left
pelvic limb. He had had lameness as a puppy that resolved
without treatment.
Physical examination: The left limb was swollen and the
patient’s temperature was elevated. Palpation of the right hip
joint was not possible.
hip joints.
Radiographic diagnosis: Extensive chronic modeling
changes were noted in the femoral head and neck, and in the
acetabulum. Little remained of the original femoral head. The
diagnosis was that of secondary arthrosis probably following a
slipped femoral capital epiphysis. The right hip joint was nor-
mal.
Treatment/Management: An osteotomy was performed on
the left removing the badly remodeled head and neck. The tis-
sue was examined histologically.
A sample of joint fluid contained toxic neutrophils and bacte-
rial cocci . Blood cultures grew a beta hemolytic Streptococcus.
The synovium and attached soft tissues had moderate to severe
inflammatory infiltrates comprised primarily of lymphocytes
and plasma cells, with focal clusters of neutrophils.
Comments: This patient probably had had a traumatic frac-
ture with severe joint damage at a young age, followed by the
progressive development of a trauma-induced secondary
arthrosis. Presumable a bacteremia had occurred recently with
seeding in the damaged hip joint leading to the development
of a septic arthritis superimposed over the non-inflammatory
arthrosis. This changed the clinical signs abruptly.
The appearance of the joint space as seen radiographically de-
served a more thorough attention than it had received on the
first examination of the study. Chronic non-inflammatory
joint disease presents with dense subchondral bone, but in this
patient, the subchondral bone is less dense with lucent zones
and the joint space is indistinct. This latter radiographic pat-
tern is that expected with inflammatory, infectious arthritis.
Note that the left femur appears shorter than the right. This is
the result of the dog preventing full extension of the painful
left hip joint as compared with the normal right hip. In a pa-
tient such as this one, it is better to position both limbs in a
similar manner so that more accurate comparison can be made
between the two hips on the radiograph.
Did you notice the calculi within the penile urethra? This
was a clinical problem that was not recognized and thus, not
treated.
Hip joint 351
4

Case 4.56
Signalment/History: “Mac” was a five-month-old, female
Ocelot who was unable to walk on the pelvic limbs.
Physical examination: Palpation of the entire body located
numerous abnormalities in the limbs plus a marked lordosis at
the junction of the spine with the pelvis. Marked bowing of
the femurs was evident.
entire body.
Radiographic diagnosis: Malformed bones with both varus
and valgus deformities were noted with the most extensive
change affecting the lumbosacral junction, the pelvis, and the
femurs. Collapse of the body of L5 was present (white lines).
Sharp angulation suggested a fracture between the sacrum and
first coccygeal segment (white lines). A decrease in cortical
thickening was noted with double cortical shadows. Wedging
of physeal growth plates was evident (black arrows). Note the
flattening of the capital epiphyses.
Differential diagnosis: The generalized bone disease was
probably due to nutritional secondary hyperparathyroidism
with multiple pathologic fractures. The severity of the bony
changes is attributed to the young age of the cat. A similar, but
much less severe bone disease can be seen with phosphorous
retention causing calcium removal from bones due to renal
disease.
Treatment/Management: The owners admitted to feeding
the cat on a diet that consisted exclusively of meat since the
time of weaning. With a change in diet, “Mac” recovered to
the point where he could walk without discomfort. The own-
ers were cautioned that problems in defecation were likely to
occur since the collapse of the pelvic canal remained.
Comments: With the use of balanced diets, patients such as
“Mac” are not common nowadays.
4

Case 4.57
Signalment/History: “Heidi” was a 7-year-old, female
German Shepherd with a history of chronic lameness. She was
assumed to have hip dysplasia.
Physical examination: The hip joints did not palpate nor-
mally. Movement of the pelvic limbs was difficult and painful.
Muscle atrophy was prominent in the hindquarters, but was
more obvious on the right side.
Radiographic diagnosis: A chronic dorsal luxation of the
right femoral head was noted and was complicated by a bony
fragment missing from the head (arrow). Flattening of the
right acetabulum suggested chronicity of the injury. The left
coxofemoral joint was normal.
A transitional vertebral segment was located at the lumbosacral
junction with marked reactive bony spurring. The L6 lumbar
segment was shortened and malformed.
Comments: The exact nature of the original fractures was
difficult to determine because of the chronicity. It was
thought that the right hip joint was normal at the time of the
original trauma; however, the L6 lesion could have been con-
genital/developmental as well as post-traumatic. The presence
of the transitional segment as well as a sacrum with four seg-
ments supports a congenital/developmental etiology.
Hip joint 353
4

Case 4.58
4
Pre-operative
Post-operative 12 months

Signalment/History: “Taffy” was an 11-month-old, female
Golden Retriever, who had had bilateral femoral head ostec-
tomies as treatment for bilateral hip dysplasia.
Radiographic procedure: Radiographs were made to eval-
uate the outcome of the surgery. The original pelvic radio-
graphs plus the immediate post-operative studies were avail-
able for comparison. It was thought the calcar was more
prominent post-operatively than desired.
Radiographic diagnosis: Radiographic studies made 12,
16, and 24 months after surgery clearly showed the secondary
flattening of the acetabular cups and remodeling of the
femoral necks. While these changes were rather frightening in
appearance, they were anticipated in surgery of this type in a
large dog as bone atrophy and remodeling occur. Free miner-
alized fragments were probably synovial osteochondromas
formed in association with the changes in the joint capsular
remnants (arrows). Soft tissue atrophy suggested that the dog
was having difficulty in regaining use of its pelvic limbs. The
modeling pattern seen on the right side is more desirable than
that seen on the left.
Comments: Radiographs made following trauma or in post-
operative patients demonstrate bone in a healing phase and
may have features that are rather remarkable in the demon-
stration of the patterns of modeling.
Hip joint 355
4
16 months 24 months

Case 4.59
Signalment/History: “Chewy” was an 8-month-old, fe-
male Retriever mixed breed who had been hit by a car and
was lame on the right pelvic limb.
Physical examination: Crepitus was detected in the right
hip joint. Movement of the limb caused considerable pain to
the dog.
Radiographic procedure: Radiographs of the pelvis were
made with the limbs in flexion to reduce the pain.
Radiographic diagnosis (day 1): A physeal fracture left the
right femoral head remaining within the acetabulum (arrow).
The opposite hip joint was normal.
Treatment/Management: An attempt was made to stabilize
the capital epiphysis using small wires. The resulting position
of the head relative to the neck was not anatomical.
Radiographic diagnosis (day 30): The radiographs made
one month later showed the “apple core” appearance of the
femoral neck indicating acute bony resorption (arrow). The
femoral head remained essentially unchanged indicating a lack
of blood supply. The modeled neck appeared to have united
with the head. The normal appearance of the acetabular roof
suggested that it was weightbearing and was a good prognos-
tic sign.
Comments: The speed of resorption of the femoral neck in
slippage of the capital epiphysis in the young dog is always a
frightening radiographic feature and though expected, it may
incorrectly suggest infection or even malignant resorption.
4 Day 1 Post-operative
Day 30

Case 4.60
Signalment/History: “Casey” was a 1-year-old, male Ger-
man Shepherd mix who had been hit by a car several days pre-
viously and would not bear weight on his left pelvic limb. The
referring clinician had diagnosed a femoral head luxation.
Physical examination: Palpation of the left hip suggested
that the femoral head was luxated.
made.
Radiographic diagnosis: A luxation of the left femoral head
was associated with a fracture that had separated a large por-
tion of the head (arrow). The femoral head was luxated dorsal
to the acetabulum. The left acetabulum was normal except
that the bony fragment remained within the acetabulum. The
right hip joint was normal.
Treatment/Management: The owner was advised that
closed reduction was not possible because the bone fragment
prevented replacement of the femoral head. He refused surgi-
cal treatment and left with a dog that would be chronically
lame
Comments: “Casey” is an example of the value of radi-
ographic examination of a suspect trauma case. An uncompli-
cated coxofemoral luxation could have been reduced; howev-
er the femoral head in this case could not be reduced because
of the bony fragment positioned in the acetabulum.
The airgun pellet in the soft tissues of the right hindlimb was
an incidental finding and was unrelated to the current trauma.
Hip joint 357
4

4

Hip joint 359
4
Case 4.61
Signalment/History: “Duke” was a 1-year-old, male
Samoyed who had been hit by a car several months previous-
ly. He had become progressively lame on his right pelvic limb
with marked muscle atrophy.
Physical examination: Crepitus was noted on palpation of
the right hip joint. The muscle atrophy was marked, but not
painful. The right pelvic limb appeared shortened, suggesting
the possibility of a coxofemoral luxation.
Radiographic diagnosis: The malshapened right femoral
head and acetabulum were thought to be post-traumatic. The
right femoral head luxation was dorsal and cranial. The mus-
cle atrophy affected the right pelvic limb and indicated disuse.
A healed fracture at the junction of the middle and distal thirds
of the left femur was suggested by the thickened cortex
(arrow).
Comments: This type of injury is common in a younger dog
and apparently, the trauma had occurred just at the time of
skeletal maturation. The fracture/luxation of the femoral head
included a separation of a portion of the femoral head and
fragmentation of the dorsocranial margin of the acetabulum.
The femoral fracture had been treated with an IM pin and a
suggestion of the pin tract was seen in the distal femur. Mini-
mal callus formation remained around the fracture site. Why
treatment was only directed toward the femoral fracture and
the right hip joint injury was not treated, remained an unan-
swered question.

4
Femur
The femur is a long, tubular bone that frequently suffers the
effects of being hit by a car with resulting midshaft fractures.
In addition, the proximal femur is unique clinically with re-
spect to injuries of the femoral head and neck, while fractures
to the distal femoral condyles form another clinically impor-
tant injury (Table 4.7).
Fractures of the midshaft are often spiral and contain a large
butterfly fragment with marked displacement of the frag-
ments, including overriding. If patient positioning in such cas-
es includes a VD view of the pelvis, additional injury can oc-
cur to the soft tissues when attempts are made to extend the
limb for this view. It is much less traumatic to place the
hindlimb into a fully flexed position or if the patient is small,
the body can be positioned in a “sitting position” with the
limb extended.
Injury to the proximal femur includes the femoral head and
neck, as well as both trochanters. In the immature patient,
slippage of the capital epiphysis results in a loss of blood sup-
ply to the femoral head because of the intracapsular location of
the physis. Subsequent femoral head necrosis will occur unless
the reduction and fixation is immediate, and anatomically suc-
cessful. With a coxofemoral luxation, a tearing of the ligament
of the femoral head may result in an avulsion fracture from the
fovea of the femoral head or a fracture from the margin of the
acetabulum. In older patients with a more severe trauma, a
splitting of the femoral head can occur.
Avulsion of the greater trochanter results from a tearing of the
piriformis and middle gluteal muscles, while avulsion of the
lesser trochanter results from a tearing of the tendon of the il-
iopsoas muscle
Distal fractures may result in physeal separation of the femoral
condyles with their subsequent caudal and proximal displace-
ment, the result of a contraction of the semimembranosus
muscle. Distal fractures may extend into the femoral trochlea,
where they interfere with the femoropatellar joint. Other in-
juries to the patella can occur following luxation with or with-
out fracture.
Table 4.7: Radiographic signs of femoral trauma
1. Pattern of fracture of the femoral head and neck in the immature animal
(Cases 4.46, 4.59, 4.105, 4.109, 4.128, 4.130, 4.132 & 4.133)
a. physeal fracture of the femoral head (Cases 4.59, 4.105, 4.109 & 4.128)
b. avulsion fracture from the fovea of the femoral head (Case 4.48)
c. avulsion of the greater trochanter (Case 4.105)
d. avulsion of the lesser trochanter (Case 4.130)
2. Pattern of fracture of the femoral head and neck in the mature animal
a. femoral neck fracture
b. femoral head fracture (Case 4.57)
c. intertrochanteric fracture
3. Injury includes an acetabular fracture
4. Fracture patterns of the femoral shaft
a. spiral
b. with butterfly fragments (Cases 4.63, 4.64 & 4.68)
c. comminuted (Cases 4.104 & 4.121)
d. fragment over-riding (Cases 4.68 & 4.104)
5. Fracture patterns of the condylar area
a. physeal separation of the femoral condyles (Case 4.131)
b. fracture line into the trochlea (Case 4.62)
c. injury causing traumatic patellar luxation (Case 4.43)
d. pathologic fracture (Case 4.64)
e. patellar fracture (Cases 4.65 & 4.135)
6. Patterns of soft tissue injury
a. intramuscular hemorrhage
c. muscle atrophy (Cases 4.32, 4.35, 4.43, 4.48, 4.57, 4.58, 4.61, 4.99,
4.104 & 4.124)

Femur 361
4
Signalment/History: A young, female cat had been found
by the roadside and was brought to the clinic unable to walk
on the right pelvic limb.
Physical examination: Crepitus and instability were noted
in the right stifle joint and a fracture/luxation was suspected.
An extensive laceration was present on the medial aspect of
the upper limb.
right pelvic limb.
Radiographic diagnosis: An articular fracture extended
from the distal medial femoral cortex into the intercondylar
fossa destroying the trochlear of the femur. Distraction of the
medial condyle was medial and caudal. The small, mineralized
shadow cranial to the joint space within the thickened patel-
lar tendon suggested a partial tear of its attachment to the tib-
ial crest. The patella was intact but malpositioned. Joint effu-
sion was extensive and the infrapatellar fat pad could not be
identified. Subcutaneous emphysema was noted.
Treatment/Management: Two cancellous screws reposi-
tioned the condyle and healing was progressing nicely at one
month post-trauma. The cat was lost to follow-up after that
time.
Case 4.62

Case 4.63
Signalment/History: “Pablo” was
a 17-month-old, male Siamese cat,
who had been hit by a car three days
previously. A fragment of bone pro-
truding through a wound in the
hindlimb was cleaned and “re-
placed” by the referring veterinari-
an. The cat was referred for defini-
tive treatment of the fracture.
Physical examination: The hind
limb was swollen and discolored and
the fracture was obvious.
Radiographic procedure: A lat-
eral radiograph was made of the
pelvic region.
Radiographic diagnosis (day 3,
femur): An acute midshaft fracture
of the femur was characterized by
marked over-riding and separation
of the major fragments with four
large butterfly fragments at the frac-
ture site.
Treatment/Management: The
fracture was treated with internal
fixation and the cat discharged.
One month later, the owner found
the cat to be painful on handling and
somewhat dyspneic. “Pablo” was re-
turned to the clinic and radiograph-
ic studies made of the thorax.
4
Day 33
Day 3

Radiographic diagnosis (day 33, thorax): The increase in
fluid density in the caudal thorax suggested pleural fluid. The
cardiac silhouette had shifted dorsally and the diaphragm could
not be identified. An oral contrast meal was administered and
the displaced stomach and small bowel were diagnostic of a
diaphragmatic hernia.
Comments: “Pablo” is an example of a case in which all the
attention was directed toward the most obvious injury, the
fractured femur. It is quite probable that the cat was main-
tained in the clinic awaiting surgery, underwent a surgical
procedure, recovered and was returned to the client without
anyone listening to the thorax. However, it is also possible that
although the injury to the diaphragm occurred at the time of
the original trauma, the cranial displacement of the bowel into
the thoracic cavity did not occur until later, when the cat be-
came dyspneic.
Outcome: The hernia was successfully repaired and “Pablo”
returned home again.
Femur 363
4

Case 4.64
Signalment/History: “Caesar” was a 9-year-old, male
Rottweiler who had experienced a short fall and became
acutely non-weight-bearing on his left hindleg. He had been
diagnosed as having bilateral hip dysplasia three years earlier.
Physical examination: Palpation of both hip joints was
painful for the dog.
Radiographic diagnosis: A severe, deforming arthrosis of
both hip joints was secondary to bilateral hip dysplasia. In ad-
dition, a highly destructive medullary lesion with a patholog-
ic fracture in the distal left femur was thought to be due to a
primary bone tumor. Soft tissue swelling was event around the
distal femur.
Treatment/Management: “Caesar” presented a difficult
diagnostic problem. He was known to have chronic pelvic
limb lameness due to secondary arthrosis from hip dysplasia;
however, the clinical signs had changed markedly following a
minor trauma when he became non-weightbearing on his left
hindlimb. The destructive nature of the lesion plus the patho-
logic fracture strongly suggested a primary bone tumor. Sur-
gical biopsy examination following limb amputation proved
the lesion to be a centrally located osteosarcoma.
4

Stifle joint
The stifle or knee joint is a frequently injured component of
the pelvic limb (Table 4.8). It consists of three separate joints:
(1) the femoropatellar joint, (2) the medial femorotibial joint,
and (3) the lateral femorotibial joint. Trauma often damages
the ligaments or tendons more often than it causes fracture or
luxation of the bony structures of this joint. Radiographic di-
agnosis of femorotibial joint disease is often inaccurate because
of the failure of the articular surfaces of the femur and tibia to
meet closely. The two menisci separate these bones and take
part in protecting the articular cartilage. Consequently, the
pattern of arthrosis is altered and consists primarily of enthes-
ophyte formation.
In many dogs, the high frequency of cranial cruciate ligament
injury leads to chronic arthrosis and often enhances any acute
traumatic injury. In the older patient, the pattern of radio-
graphic features associated with cruciate or collateral ligament
or meniscal disease often covers a more acute lesion such as a
suppurative arthritis.
The patella and trochlear notch of the distal femur are of par-
ticular importance since they may be affected in any congen-
ital/developmental diseases in which the patella tends to lux-
ate. They are also the first to show enthesophytes associated
with developing arthrosis. Skyline views are important in the
evaluation of this articulation.
Fractures of the distal femur may involve the distal growth
plate with caudal and proximal displacement of the epiphysis.
In the mature dog, fractures may be a Salter-Harris type III
and enter the joint space through the intercondylar space of
the femur.
The tibial crest with its attachment to the patellar tendon suf-
fers frequently from avulsion. The clinical importance is less-
ened because the injury does not involve the stifle joint. This
is discussed later in the section on the tibia.
Clinical signs thought to be due to injury to the hip joint or
lumbosacral joint may originate from stifle joint disease. A dog
that shows pain when pressure is placed on the back may be
telling you about its stifle joint instead of the hip joint or LS
junction. For this reason, inclusion of the stifle joint in any ra-
diographic evaluation may be important.
Table 4.8: Radiographic signs of trauma to the stifle joint
1. Pattern of stifle joint luxation
a. uncommon
b. patellar luxation (Cases 4.43 & 4.67)
c. often with extensive ligamentous and tendenous injury
2. Pattern of articular fracture
a. fracture line may enter through the intercondylar space (Case 4.62)
b. patellar fracture is possible (Cases 4.65 & 4.135)
3. Pattern of superimposed infection
a. uncommon in the stifle
4. Pattern of joint effusion
a. infrapatellar fat pad is displaced or not seen clearly
b. joint capsule is displaced caudally
c. collateral ligaments are thickened and displaced abaxially
d. possible joint capsule tear (Case 4.66)
Stifle joint 365
4

Signalment/History: “Poncho” was a 7-year-old, male
German Shepherd mixed breed that had jumped out of a boat
onto land four days previously and had not used his right
pelvic limb since that time.
Physical examination: The stifle joint was swollen exten-
sively making deep palpation impossible.
Radiographic diagnosis (day 4): A comminuted fracture
of the patella had fragment separation. The soft tissue swelling
included some joint effusion.
Comments: Because of his older age, with this type of trau-
ma, “Poncho” could not avulse the tibial crest, but instead
fractured the patella. The age of the comminuted fracture was
difficult to ascertain, but some of the fragments had sharply
defined margins indicating a recent injury as described by the
owners.
Case 4.65
4

Case 4.66
Signalment/History: “Moe” was
a 3-year-old, male Afghan Hound
who had got in a fight with other
dogs and was subsequently acutely
lame in the left pelvic limb.
Physical examination: The stifle
joint was unstable with no evidence
of crepitus.
Radiographic procedure: Studies
of the stifle joint included stress
views.
Radiographic diagnosis: Instabil-
ity in the stifle joints suggested tear-
ing of both the cranial cruciate and
lateral collateral ligaments. No frac-
ture fragments could be identified.
A persistent infrapatellar fat pad sug-
gests that the capsule was torn and
joint fluid and or hemorrhage had
escaped into the periarticular tissues.
luxation was not treated.
Comments: Meniscal injury can-
not be determined radiographically
and its presence would further com-
plicate treatment.
Stifle joint 367
4

Case 4.67
Signalment/History: “Lisa” was a 1-year-old, female
German Shepherd who had been hit by a car one week pre-
viously. She had been examined at an emergency clinic and no
fractures were identified; any injury was assumed to be liga-
mentous.
Physical examination: At presentation, she was non-
weightbearing on the left pelvic limb and showed pain on
flexion and extension of the stifle and hock. The hips did not
palpate in a normal manner.
pelvis and left stifle joint.
Radiographic diagnosis (hip joints): Both femoral heads
were subluxated with thickened femoral necks. The neck on
the right had a “Morgan’s line” (white arrow) suggestive of
early arthrosis associated with hip dysplasia. The positioning
of the hip on the left prevented the same degree of radio-
graphic evaluation. Bilateral hip dysplasia was present.
Radiographic diagnosis (stifle joint): The patella on the
left was luxated laterally and a fracture line in the epiphysis ex-
tended from the area of the tibial crest through the lateral tib-
ial cortex (white arrows). The fracture line had become indis-
tinct because of the minimal displacement of the fragment and
the time since the trauma. Massive soft tissue swelling with
joint effusion was present. In conclusion, the tibial fracture
was articular with a patellar luxation.
Treatment/Management: “Lisa” was not treated and was
lost to follow-up with the knowledge that she would develop
hip and stifle arthrosis.
Comments: The fracture, luxation and joint effusion were
not detected on physical examination immediately after the
accident nor were they noted on the original radiographs. It
was assumed that the subluxation on the left was due to the
dysplasia. Traumatic subluxation of a healthy hip joint is un-
common, if not impossible.
4

Tibia
Fractures of the tibia are common with spiraling, comminut-
ed, midshaft fractures being the most common (Table 4.9).
Distally, fractures of the medial malleolus are associated with
tibiotarsal luxations. Fibular fractures occur in conjunction
with the tibial fractures. Type II physeal fractures of the prox-
imal epiphysis are rather common and may occur alone or
with an avulsion of the tibial crest. Apparent Type I fractures
of the distal tibial may often be actually a Type II. A separate
injury may result from increased tension on the patellar ten-
don, which results in a proximal displacement of the tibial
crest.
Table 4.9: Radiographic signs of tibial trauma
1. Pattern of fracture in the immature animal
a. physeal fracture of the proximal tibial plateau (Cases 4.67, 4.121
& 4.122)
b. avulsion fracture of the medial malleolus
c. avulsion of the tibial crest (Cases 4.119, 4.123, 4.134, 4.135 & 4.136)
d. physeal injury to the distal tibia (Cases 4.120, 4.128 & 4.140)
e. injury to the tibial epiphysis (Case 4.62)
2. Pattern of fracture of the tibial shaft
a. often long oblique or spiral fracture (Cases 4.69, 4.71 & 4.137)
b. usually involves the fibula (Case 4.70)
c. greenstick fracture (Case 4.70)
d. with butterfly fragments (Case 4.73)
e. malleolar fracture (Cases 4.75 & 4 76)
3. Pattern of soft tissue injury
a. intramuscular hemorrhage
Tibia 369
4

4

Case 4.68
Signalment/History: “Moonshine” was presented as an
emergency case with a history of trauma. She was an 8-year-
old, female mixed breed unable to walk on her right hindlimb.
Physical examination: Palpation indicated a midshaft frac-
ture of the femur.
upper hindlimb.
Radiographic diagnosis: A transverse fracture at the junc-
tion of the middle and distal thirds of the femur had a single
small butterfly fragment. Marked overriding of the fragment
ends was noted.
Treatment/Management: The fracture was treated with
placement of a ten-hole plate with an additional three screws
placed as lag screws. A cancellous graft was used at the fracture
site. The fracture healed in the expected manner with radio-
graphs made after two months showing early healing of the
fracture.
Comments: The unfortunate part of this case is that the se-
vere arthrosis in the adjacent stifle joint was not appreciated by
the clinician prior to fracture repair and the owners did not
suggest any problems in walking prior to the trauma. As a re-
sult of non-locomotion during the fracture healing, motion of
the previously diseased stifle joint became more limited. The
fracture healed nicely, but “Moonshine” was left with severe
lameness because of the pre-existing stifle joint disease.
Tibia 371
4

Case 4.69
Signalment/History: “Not Yet” was a 4-month-old, male
Samoyed who had caught his left pelvic limb in a fence sever-
al hours previously.
Physical examination: He was non-weight-bearing and the
limb was painful on palpation. Swelling was not detected.
Radiographic procedure: Radiographs of the left tibia were
made.
Radiographic diagnosis (day 1): A spiral fracture in the left
tibia appeared to be recent with no callus formation and with
little displacement of the fragments (arrow). Minimal soft tis-
sue swelling was evident suggesting a low energy trauma. The
growth plates were open and appeared normal. A generalized
secondary osteopenia was present that could have had a nutri-
tional or renal etiology.
Radiographic diagnosis (day 14): The fracture was seen in
a healing stage.
Treatment/Management: The fracture was thought to heal
more slowly than expected considering the young age of the
dog and minimal trauma to the limb. The bones remained os-
teopenic without the cause having been determined.
Comments: The first study was performed with the limb
wrapped in a supporting bandage. While this is a common
practice in trauma patients, there is a danger that an important
aspect of the injury may not be identified. Radiographs made
following removal of the bandage, cast, or splint should be
evaluated prior to any surgical procedure.
4
Day 1 Day 14

Case 4.70
Signalment/History: “Missy” was a 4-month-old, female
Labrador Retriever puppy injured probably when hit by a car.
Physical examination: She was lame on the left pelvic limb
that palpated as though there was a tibial fracture.
tal portion of the left pelvic limb.
Radiographic diagnosis: A comminuted midshaft fracture
of the tibia was seen with cranial and lateral angulation of the
distal fragment and minimal impaction of the fragments. An
associated fibular fracture was present. Growth plates and ad-
jacent joints appeared unaffected.
A simple fracture of the midshaft of the 4th
metatarsal bone and
a comminuted fracture of the midshaft of the 3rd
metatarsal
bone were noted (arrows). Soft tissue swelling was prominent.
Treatment/Management: All the fractures were treated by
placement of the entire limb in a splint. The fractures were
healed on follow-up radiographs made one month after the in-
jury. The distal tibial fragment healed with cranial angulation
and a 10-degree lateral angulation. The distal tibial physeal
growth plate had closed.
Comments: In a puppy, the malalignment of the fragments
will probably correct with further bone growth. In a case such
as with this dog, the further growth of the tibia should be
monitored.
Tibia 373
4

Case 4.71
Signalment/History: “Baby” was a 17-year-old, female
Pointer who had injured her right leg three weeks previously.
Treatment had consisted of an external cast.
Physical examination: Examination was limited because of
the cast.
right tibia with the cast in place.
Radiographic diagnosis: A long oblique fracture within the
proximal half of the tibia contained one rather long fissure line
in the distal fragment. The major fracture line extended to
within 1–2 cm of the stifle joint. Apposition and alignment of
the fragments was good with a 1-cm separation of all frag-
ments. No callus was identified. The fibula had a delayed
union midshaft fracture as well.
All the bones appeared to contain small lucent cavities, espe-
cially the proximal tibia and the femoral condylar region,
which suggested a generalized destructive disease.
Differential diagnosis: First, it was strange that no callus had
formed in a three-week-old fracture. The delay in healing was
thought to be due to the severity of the soft tissue injury, the
failure to stabilize the fragments, the older age of the patient,
plus the possible formation of a radiolucent callus in unstable
fractures. Secondly, the pattern of lucencies was correctly
thought to be due to the overlying cast material. The answer
to the problem was obtained by observation of the more
healthy appearing bone tissue in the femur, an area not cov-
ered by the cast.
Treatment/Management: The fracture had a well-formed
fibrocartilagenous callus that had fixed the fragments in posi-
tion at the time of the radiographs, so treatment with the ex-
ternal cast was continued. Subsequent radiographs made at
three months following injury showed the fragments in the
same position as before and with minimal callus formation
around both the tibial and fibular fractures.
Comments: Any change in the nature of the overlying soft
tissues may influence how the bone tissue appears in a skeletal
study. Metallic objects or gravel create a more opaque shadow,
while air or gas creates a lucent pattern. Other objects such as
bandage tape or wet hair create a pattern in the overlying den-
sity and alter the appearance of the bone possibly causing mis-
diagnosis as happened in this patient. The limit of the cast can
be seen in the mid-femoral region.
4

Case 4.72
Signalment/History: “Mitsy” was a 3-month-old, female,
mixed-breed puppy that had been stepped on by her owner.
She was lame on her left hindleg.
Physical examination:She was unable to bear weight on the
left pelvic limb. No crepitus was elicited; however, deep pal-
pation of the tibia was painful.
Radiographic procedure: Both views were made of the
tibia.
Radiographic diagnosis: A spiraling, incomplete (green-
stick) fracture in the midshaft of the tibia was seen.
Differential diagnosis: Nutrient foramina can cause lucent
lines that can appear as fractures.
Treatment/Management: Having learned the cause of the
lameness, it was possible to confine the puppy to cage rest for
a short time to permit healing of the fracture.
Comments: The diagnosis of the fracture eliminated a pri-
mary soft tissue injury as the cause of the lameness.
Tibia 375
4

Case 4.73
Signalment/History: “Spurs” was a 2-year-old, male Bor-
der Collie who had been missing from home for four days and
had returned with an injury to his right pelvic limb.
Physical examination: An open fracture of the right mid-
shaft tibia appeared to be comminuted. Palpation of the pelvic
region detected a left coxofemoral luxation.
pelvis and right pelvic limb.
Radiographic diagnosis: The severely comminuted open
midshaft fracture of the tibia had multiple butterfly fragments.
A fissure fracture line extended into the distal fragment to a
distance 1 cm proximal to the end of the bone. Minimal over-
riding of the major fragments caused a cranial and proximal
malposition of the distal fragment with slight lateral angula-
tion.
A luxated left femoral head was seen with a small avulsion of
bone from the fovea capitus femoris (white arrows). Avulsion
of the ischiatic tuberosity (black arrows) was adjacent to debris
on the skin that compromised visualization of the bony frag-
ment.
4

Treatment/Management: The tibial fracture was treated
with an external KE apparatus. The coxofemoral luxation was
reduced by open reduction.
The tibial fracture site became infected. Multiple sequestra
were identified and were removed surgically six weeks after
the first treatment and a new KE apparatus was put into posi-
tion.
Radiographs were made of the tibia five months after treat-
ment.
Comments: The appearance of bones during healing follow-
ing both trauma and surgery can be altered remarkably with
confusion centering on whether the combination of lytic and
productive changes at the fracture site are associated only with
healing of the fracture or may be due to the presence of un-
derlying osteomyelitis The decision of a secondary bone in-
fection is best made utilizing the clinical status of the patient
in conjunction with the radiographic patterns.
Tibia 377
4
5 months

4

Signalment/History: “Jed” was a 3-month-old, male
Spaniel fed a diet of bitch’s milk and commercial food. Despite
this diet, he had a history of generalized weakness and inabili-
ty to walk.
Physical examination: The left pelvic limb was particularly
sensitive to palpation.
pelvic limb. Lateral views were made of the forelimbs.
Radiographic diagnosis: Generalized bone disease was ev-
ident and was characterized by thin cortices, epiphyses with
lucent centers, while the metaphyseal bone was more dense
than usual. Lateral angulation of the tibia on the left was sec-
ondary to a pathologic fracture in the proximal metaphysis.
Differential diagnosis: While the pathologic fracture was
identified, the etiology was not easily determined.
The radiodense rings around the epiphyses are seen in scurvy
or Barlow’s disease and are called Wimberger’s ring sign.
While this is typical for vitamin C deficiency, there is no sign
of subperiosteal hemorrhage in this patient, which is also a
classic feature for this condition.
In hypothyroidism, the bones appear to develop normally, al-
though at a delayed rate. In this dog, the size of the epiphyses
is thought to be normal for its age.
Case 4.74
Rickets is probably the most likely diagnosis except for the his-
tory of a healthy diet. Rickets can be vitamin D resistant, as-
sociated with a decreased intestinal absorption of calcium or
phosphorus, or due to renal tubular disorder with a loss of cal-
cium through the kidneys.
Treatment/Management: “Jed” was euthanized. However,
a post-mortem examination of the bones failed to produce an
etiology for the bone disease. Multiple pathologic fractures
were seen at the costochondral junctions (white arrows) in ad-
dition to the long bone lesions.
Comments: Bone surveys may identify abnormal skeletal
maturation, but often cannot determine the specific etiology.
Also the histologic examination of the bone tissue is often not
helpful.
Tibia 379
4

Signalment/History: “Tammy” was a 5-year-old, female
Collie who had sustained multiple injuries after being struck
by a car.
Physical examination: Fractures were noted in three limbs
with severe soft tissue injury in the pelvic area. Because of the
dog’s inability to stand, injury to the right tarsal region was not
noted at first. Later, palpation of the distal right pelvic limb in-
dicated marked crepitus and instability, and a requirement for
further examination.
right tarsus five days after the trauma.
Radiographic diagnosis (day 5): A bimalleolar fracture af-
fected the medial and caudal malleolus (white arrows) with
fracture lines entering the tibiotarsal joint resulting in injury to
the articular surface.
Treatment/Management: Unfortunately, a fracture in an-
other bone became infected and the attention of the clinicians
was directed toward that limb ignoring the right tarsal injury.
All the other fractures eventually healed and “Tammy” was
discharged; however, the right hock was left untreated with
the certainty of development of a post-traumatic arthrosis.
Case 4.75
Comments: The small sliver of bone adjacent to the calca-
neus (black arrows) was at the site of attachment of the long
part of the lateral collateral ligament and probably represents
an avulsion fracture following tearing of that structure. Al-
though not articular and not requiring re-attachment, this in-
jury does further indicate the severity of the trauma.
4

Signalment/History: “Phillip” was a 7-year-old, male Aus-
tralian Shepherd who had injured his right hindlimb while
playing with his owner.
Physical examination: The right hock region was swollen
and painful to palpation.
Radiographic procedure: Two views of the tarsus were
made.
Radiographic diagnosis: The tip of the medial malleolus
was avulsed and the lateral malleolus was fractured free.
Swelling surrounding the joint suggested a soft tissue injury
associated with the sprain.
Treatment/Management: The lateral malleolar fracture
was reduced by a tension band apparatus. The chip fragment
from the medial malleolus was removed with an attempted
soft tissue reattachment. The lateral malleolar fracture was
healed in six weeks but the joint appeared unstable.
Case 4.76
Comments: An injury of this type can be further evaluated
pre- and postoperatively by the use of stress radiography to de-
termine joint stability. The failure to treat the medial malleo-
lar fracture with greater success may have left both the short
and long part of the medial collateral ligament damaged and
the joint unstable.
Tibia 381
4

Hindfoot
The skeleton of the hindfoot includes the tarsus, metatarsus,
phalanges, and the small sesamoid bones. All are small and
trauma can result in crushing or comminution with the im-
paction preventing an easy detection of the fracture lines. Be-
cause of its morphology, multiple views are usually made of
the foot.
Another helpful examination method is the use of stress views
in which the foot is placed in hyperextension, hyperflexion,
medial or lateral stress, or rotation. The injury to the soft tis-
sues supporting the joints can be detected with these stress
studies, while corner or avulsion fractures can be seen more
clearly.
The calcaneous is unique as there is the possibility of separa-
tion of the calcaneal tuber in the skeletally immature patient
and fracture through the body of the calcaneous in the mature
one.
The proximal sesamoid bones are not as frequently injured in
the hindfoot as in the forefoot.
The third phalanx is unique as its base contains the articular
surface and the extensor tubercle. The distal part of the pha-
lanx is a laterally compressed cone shielded by the horny claw,
the root of which fits proximally beneath the ungual crest.
4

Case 4.77
Signalment/History: “Tiac” was a 3-year-old, female Aki-
ta with an injury of unknown origin to the right tarsal region
resulting in a marked instability of the joint.
Physical examination: The tarsus was unstable on palpation
and soft tissue swelling was prominent.
Radiographic procedure: Multiple radiographs of the tarsus
were made including stress views.
Radiographic diagnosis: Proximal intertarsal joint luxation
with small avulsion fractures (black arrow) probably represent-
ed a tearing of the plantar ligament, especially the band that
leaves the caudolateral surface of the calcaneous and attaches to
the base of metatarsal V. Actually, fragmentation was minimal
considering the degree of malalignment generated by the hy-
perflexed view. The failure to produce displacement medially
or laterally suggests that the collateral ligaments had received
only minimal injury.
Treatment/Management: A bone plate was placed on the
caudolateral aspect of the tarsus with the use of a cancellous
graft to obtain an arthrodesis.
Radiographs were made three months later when “Tiac” was
again lame. These showed that one of the screws was broken
with the head having “backed out”. However, the arthrodesis
was thought complete at that time. Soft tissue swelling was ap-
parent.
Comments: Stress studies are valuable in locating the exact
location and extent of an injury. The soft tissue mineralization
proximal to the tip of the calcaneous (white arrows) is proba-
bly not associated with the trauma.
Hindfoot 383
4

Signalment/History: “Rascal”, an 11-year-old, female
Spaniel, was in the hospital for an examination related to her
diet when the clinician noted that the 2nd
digit on her right
pelvic limb was smaller than normal and the nail badly de-
formed. It was thought prudent to radiograph the foot.
foot.
Radiographic diagnosis: Atrophy of all three phalanges of
the 2nd
digit was marked. The 3rd
phalanx was particularly
malformed with only a small residual of the nail bed remain-
ing (arrows). The distal end of the 2nd
phalanx had undergone
“penciling” and was luxated from the 3rd
phalanx. No soft tis-
sue swelling or mass lesions were noted. No pattern of aggres-
sive bone destruction was noted.
The diagnosis was bone atrophy following a traumatic luxation
of the 3rd
phalanx.
Differential diagnosis: Lesions affecting a nail include those
that are traumatic, inflammatory, or neoplastic. Determina-
tion of the etiology would assist in determining the appropri-
ateness of amputation as a treatment.
Case 4.78
Treatment/Management: In the absence of clinical or ra-
diographic evidence suggesting either an inflammatory or
neoplastic lesion, and since the malformed nail did not inter-
fere with her walking, the lesion was not treated.
Comments: Suspect lesions of the 3rd
phalanx should be
studied diligently and are often amputated if thought to be due
to a chronic inflammatory or malignant lesion. Diagnosis is
then made from examination of the surgical specimen.
4

Case 4.79
Signalment/History: “Lady” was a 2-year-old, female cross
breed whose owner noticed that she was not walking correct-
ly on her left hindlimb.
Physical examination: Palpation detected crepitus within
the left metatarsal bones. No soft tissue injury was evident.
Radiographic procedure: Views of the left hind foot were
made.
Radiographic diagnosis: Comminuted fractures were
noted in the proximal 1
/3 of the 2nd
and 3rd
metatarsal bones
(arrows). Apposition and alignment of the fragments remained
almost anatomical. Soft tissue swelling was minimal. The in-
jury appeared recent.
Treatment/Management: Because of the good position of
the fragments, the foot was heavily bandaged and the owner
advised that if they restrict movement, healing should take
place within a short time.
Comments: Because each fracture is unique as to the energy
level of the trauma, the bone fractured, the nature of the frac-
ture, the injury to the soft tissue, the method of fracture re-
duction, the compliance of both patient and owner during
healing, as well as the health of the patient, it is difficult to pre-
dict an exact schedule of expected healing.
Hindfoot 385
4

Signalment/History: “Tiko”, a 2-year-old, male Rottwei-
ler, was presented with the primary complaint of acute lame-
ness of the left pelvic limb, first noticed the previous morning.
Physical examination: The dog was bearing only partial
weight on the left pelvic limb. Pain was elicited on palpation
of the foot, especially around the swollen 5th digit.
Radiographic procedure: Multiple studies were made of
the foot.
Radiographic diagnosis: An acute intraarticular oblique
fracture (arrows) with minimal comminution extended the
length of the 2nd
phalanx. A transverse fracture (arrow) in the
proximal portion of the 3rd
phalanx was seen to extend into
the ungal crest.
Treatment/Management: The foot was supported awaiting
healing of the phalangeal fractures.
Comments: Note the multiple “string-like” film artifacts
caused by hair inside the cassette.
Case 4.80
4

4.2.2 Radiographic features of axial
skeleton injuries
The traumatized chest wall often has radiographic lesions re-
vealing injury to the soft tissue and ribs (Table 4.10). Radio-
graphy defines and evaluates the extent of the underlying
damage. Clinically, any injury of the chest wall results in a di-
minished efficiency in respiration and restricted expansion of
the rib cage. The skeletal structures injured in the traumatized
thorax include the vertebrae, ribs, costochondral junction, and
sternebrae. Injury to the contents of the thoracic cavity is dis-
cussed fully in the section on thoracic injury (Chap. 2).
Table 4.10: Radiographic features of thoracic wall injury
1. Soft tissues
a. swollen
b. subcutaneous air (Case 4.81)
I. pockets
II. linear distribution
c. debris on skin and within soft tissues
d. soft tissues
I. torn intercostal muscles
II. injured skin and subcutaneous tissues
2. Ribs
a. fractures
I. undisplaced fragments (Case 4.81)
II. malpositioned fragments
III. multiple fragments (“flail chest”) (Case 4.81)
b. injury near the costovertebral joints (Case 4.82)
c. injury near the costochondral joints (Case 4.74)
3. Sternal injury (Cases 4.82 & 4.83)
Radiographic features of axial skeleton injuries 387
4

4.2.2.1 Disruption of the thoracic wall
Signalment/History: “Dobie” was an 8-year-old, male
mixed-breed Poodle who had been kicked by a horse several
hours previously and was brought to the clinic because he was
not breathing normally.
Physical examination: A depression type defect was noted
in the left thoracic wall on palpation with a small break in the
skin. The dog was open-mouth breathing and thoracic radi-
ographs were ordered.
with as little distress to the patient as possible.
Radiographic Interpretation: Fractures of the left 4th
, 5th
,
and 6th
ribs (white arrows) with free fragments caused a flail
chest with collapse of the underlying left middle lung lobe.
Subcutaneous emphysema was present on the left (black ar-
row). The only sign of pleural fluid was a thickening of the
shadow of cardiophrenic ligament in the left hemithorax and
suggested a possible hemothorax. The cardiac silhouette had
shifted toward the left.
No evidence of pneumothorax was present and the medi-
astinum was of normal width. The right lung was normal in
appearance. The diaphragm appeared intact.
Case 4.81
Treatment/Management: “Dobie” was treated conserva-
tively and discharged to the owner after three days.
Comments: Comparison of the two halves of the thoracic
cavity on the DV or VD view provided useful information in
diagnosis. The radiolucent lines on the right chest wall were
due to fat and needed to be separated from the irregular radio-
lucent pattern due to the subcutaneous air on the left.
4

Disruption of the thoracic wall 389
4

Case 4.82
Signalment/History: “Tom” was a mature male cat with a
history of hemangiosarcoma, who was presented for examina-
tion for metastatic disease.
made.
Radiographic diagnosis: The airway shadows were coarse
with a pulmonary bulla positioned just cranial to the di-
aphragm on the right side. No metastatic nodules were noted.
A chronic sternal luxation had resulted in a displaced 3rd
sternebrae, which had decreased bone density typical of disuse
atrophy (arrow). Pleural thickening around the protruding
bone was not evident.
Treatment/Management: No treatment was offered for the
sternal lesion.
Comments: Often chronic traumatic lesions are noted as in-
cidental findings. In this patient, repair had occurred and the
luxation was stable. No signs of adjacent pleural or pulmonary
lesions were present.
4

Case 4.83
Signalment/History: “Tom” was a 1-year-old, male cat
with generalized muscle atrophy and weakness. The clinical
history was non-contributory.
Physical examination: Palpation of the caudal ribs and ster-
num indicated a marked displacement of these structures.
Radiographic procedure: Routine thoracic radiographs
were made because the palpable abnormality suggested the
possibility of chronic trauma with rib fractures.
Radiographic diagnosis: The caudal portion of the sternum
was deviated dorsally causing the cardiac silhouette to be shift-
ed dorsally and to the left (arrows). The caudal sternebrae ap-
peared fused and were deviated toward the right. The costal
cartilages and ribs were severely deformed, but not fractured.
The lung fields were of normal inflation and density.
Differential diagnosis: While an anomaly of this type could
be post-traumatic, the sternebrae showed no signs of fracture
or luxation, and the deformity of the ribs and costal arches ap-
pears much more to be a congenital anomaly.
Treatment/Management: “Tom” was tested positively for
intestinal parasites and treated accordingly.
Disruption of the thoracic wall 391
4

4.2.2.2 Head
The head contains the skull, the brain, the mandible, the prox-
imal portion of the respiratory system, the proximal portion of
the digestive system including the teeth, and a part of the lym-
phatic system. Coverage of all of these parts is far beyond the
scope of this presentation of trauma cases. The skull is the most
complex and specialized part of the skeleton and is basically
divided into a facial plus palatal region and a braincase. Both
are indeed unique because of the variation in morphology that
man has created in the various breeds of dog and cat. The de-
termination of what constitutes normal is commonly the most
difficult decision to make.
Most fractures involve the facial portion of the skull and the
mandible (Table 4.11). These may be hit by many diverse types
of moving objects, such as cars or bullets, and thus the nature
of the injury can vary widely. Because of the lateral position
of the zygomatic arches, they are often subjected to trauma. A
fracture of mandible symphysis is common in the falling cat. If
the trauma is sufficient to cause fractures in the braincase,
death is often immediate.
Two different types of joints are present in the skull. The tem-
poromandibular joint has clinical importance and its examina-
tion radiographically is of particular interest. Special position-
ing for the lateral views is possible, plus visualization on the
DV or VD view. The other joint is the occipitoaxial joint.
Occipital condyle dysplasia plus dysplasia of the foramen mag-
num is important in the smaller breeds of dog.
Table 4.11: Radiographic signs of trauma to the head
1. Fractures often affect
a. zygomatic arches (Case 4.84)
b. nasal, premaxillary, and maxillary bones
c. frontal bones
d. mandible
e. mandibular symphysis (Case 4.84)
f. temporomandibular joints (Case 4.84)
g. teeth
2. Gunshot wounds
a. affect bone
b. affect nasal passages
c. affect soft tissues in throat
3. Foreign bodies
a. inhaled into nasal passages
b. swallowed into oropharyngeal area
4

Case 4.84
Signalment/History: “Spot” was an adult, female cat who
had been hit by a car several days previously. Following stabi-
lization of the patient, she was referred for definitive radio-
graphs.
Physical examination: A mandibular symphyseal separation
was palpable. In addition, crepitus was noted upon careful pal-
pation of the skull.
Radiographic procedure: Multiple radiographs of the head
were possible because the cat was anesthetized.
Radiographic diagnosis: Multiple fractures were identified
in the nasal, maxillary, and palatine bones, as well as in both
zygomatic arches (arrows). Temporal bone fractures were near
the mandibular fossa of the right temporomandibular joint.
Separation of the mandibular symphysis was noted.
Treatment/Management: The only fracture treated was a
stabilization of the mandibular symphysis.
Comments: A definitive radiographic study of the skull, es-
pecially of the cat, requires anesthesia, an experienced techni-
cian, and multiple views.
Head 393
4

Case 4.85
Signalment/History: A 2-year-old, male Shih Tzu would
not eat and appeared to have a “painful mouth”.
Physical examination: Pain and crepitus were evident on
palpation of the mandible.
Radiographic procedure: Multiple views were possible in
this patient following anesthesia.
Radiographic diagnosis: A fracture of the mandible be-
tween the 3rd
and 4th
lower premolars of some duration as
judged by the callus formation ventrally and medially. The
fracture line entered the periodontal space of the 4th premolar
(arrows).
Differential diagnosis: The gap at the fracture site as seen
on the oblique view remained without any callus bridging in-
dicating the possibility of a sequestrum and osteomyelitis.
Treatment/Management: The owner did not wish surgical
treatment and the dog was discharged.
Comments: Note the malposition of the corner incisors.
4

4.2.2.3 Spine
The nature of the trauma may vary from the commonly seen
patient struck by a car, to a patient who has run into a tree, to
a small puppy with a congenitally weakened OAA region,
who has been dropped from its owner’s arms.
Because of the clinically important spinal cord, subarchnoid
myelography, epidural myelography, stress radiography, and
sectional radiography are of value in additional to routine non-
contrast studies in completely understanding the various caus-
es and severity of cord injury.
The nature of spinal fractures varies depending on the patient’s
age and the nature of the trauma. In the skeletally immature,
fractures are often compressive because of the lack of strength
in the vertebral body. In the older patient, the fracture often is
of a transverse nature with the possibility of an associated lux-
ation resulting in marked malalignment of the fragments.
Other injuries result in separation of the dorsal arch with a
type of decompressive trauma that may result in less injury to
the spinal cord. Other fractures are subtler and affect only the
dorsal elements especially the articular facets. Generally, the
endplates are stronger than the trabecular bone and an injury
may spare them. In other types of trauma, the fracture line
passes through the endplate and the injury is a combination of
fracture/luxation with involvement of the vertebral body in-
cluding the endplate, the disc, and the dorsally located spinal
joints. If the disc is injured and the lesion is more of a luxation,
the only radiographic feature may be lateral, ventrodorsal, or
rotational malalignment of the vertebral segments.
What of a trauma patient with no signs of vertebral fracture,
but a protruding Type II disc seen on the myelogram. Trau-
matic disc herniation should be considered although it is not
usual. The determination of a fracture fragment within the
spinal canal on the non-contrast study is either difficult or vir-
tually impossible to determine without CT studies (Table
4.12).
A trauma patient can have injury to both the thoracolumbar
spine and the pelvis, although the prominent clinical signs
caused by the pelvic injury prevent not only a thorough phys-
ical examination that might have shown a site of pain within
the spine, but also a thorough neurological examination that
might have shown an upper or lower motor neuron lesion in
the pelvic limbs.
The concept of spinal radiography can be conveniently divid-
ed in to those done in the conscious patient and those done in
an anesthetized patient. The severely injured patient should be
carefully positioned on the table and lateral radiographs made
of the entire spine in the form of a survey study. This has the
purpose of detecting any major injuries only. This is impor-
tant information so as to avoid the possibility of increasing the
injury to the spinal cord by careless movement of the patient.
Think of what happens to the spine when you “drape” the pa-
tient over your arms while carrying it to the examination
table. The second type of study is made on the anesthetized
patient in which stress radiographs plus VD and oblique radio-
graphs can be made with the possibility of learning about seg-
mental instability and/or malalignment. Contrast studies can
be utilized in this second group of patients to determine more
of the nature of the spinal cord injury by showing cord
swelling from edema or hemorrhage, or show meningeal tear-
ing.
In the event of a definite lesion seen on a noncontrast study,
the determination of the magnitude of spinal cord injury can
be more accurately made from the neurological examination.
Be careful in assigning the level of injury to the spinal cord on
the basis of the location of the fracture fragments or noting
segmental malalignment on noncontrast studies. The extent of
fragment or segmental displacement may have been excessive
at the time of trauma causing extensive cord injury and yet the
fragments or segments can then return to a near-normal posi-
tion as seen on the noncontrast study. Use therefore the find-
ings from the neurological examination to predict the extent
of cord injury.
The spine can be subject to numerous congenital anomalies
seen throughout the life of the patient. Degenerative changes,
such as disc space collapse and the formation of spondylosis de-
formans can occur later in life. Visualization of these patterns
on spinal radiographs can be rather obvious, however, deter-
mination of their role in a trauma patient can be difficult. The
affect of trauma centered on a degenerated disc with spondy-
losis deformans and disc space collapse can be difficult to di-
agnose.
Table 4.12: Radiographic signs of spinal trauma
1. Pattern of fractures
a. compressive fractures in immature animals
b. simple fractures with or without malalignment
c. comminuted fractures with or without malalignment
d. fractures of the dorsal arch
e. fracture/luxation
f. fracture with herniated disc
2. Gunshot fracture
a. B-B or airgun pellet lodged within the spinal canal
b. shotgun pellets lodged within the spinal canal
c. high energy bullet causing fracture
3. Fracture associated with congenital anomaly
a. occipital condyles
b. dens
c. LS transitional segment
Spine 395
4

Cervical vertebrae
Case 4.86
Signalment/History: “Arno” was a 2-year-old, male Giant
Schnauzer who had been hit by a car one week previously. A
paresis followed by quadriplegia developed during the ensuing
week. A tracheostomy tube had been positioned because res-
piration was difficult.
Physical examination: A limited examination confirmed
the possibility of a cervical fracture.
Radiographic procedure: Lateral radiographs were made of
the entire spine with a single VD view of the cervical spine.
Myelography was then performed to determine the prognosis
and the course of treatment.
Radiographic diagnosis (noncontrast): A badly commin-
uted fracture of the body of C2 with rotation and angulation
that caused extensive displacement of the fragments. The
spinal canal appeared to be reduced in height. Malalignment
of the roof of the canal was marked (black lines).
Note the tracheostomy tube.
4
Noncontrast

Radiographic diagnosis (myelography): The myelogram
showed a badly distorted spinal cord; however, the extent of
cord compression was minimal (arrows). Dural injury that
would have permitted leakage of the contrast agent was not
noted.
Treatment/Management: Loss of deep pain occurred soon
after admission and the poor prognosis lead to euthanasia
Comments: The use of myelography in cord trauma can pro-
vide useful information, but the manipulation of the patient
during the examination may make its use questionable.
“Arno” was thought to have a cervical fracture, and yet, the
neck had not been placed in a protective brace during the
week following trauma. The resulting motion of the bony
fragments probably caused more cord injury.
Cervical vertebrae 397
4
Myelography

Thoracic vertebrae
Case 4.87
4

Signalment/History: “Kila” was an 18-month-old, female
Golden Retriever who had been hit by a car 24 hours earlier.
Physical examination: She could not walk when presented.
She had superficial pain reflexes, a normal panniculus reflex,
and normal patellar reflexes.
thorax with additional studies centered on the region of
T5–6.
Radiographic diagnosis: A heavy pattern of alveolar fluid
in the right lobes produced air-bronchogram patterns. The
diaphragm was intact. No pleural fluid was noted. The chest
wall was normal. The cranial mediastinum was thought to be
widened.
A fracture-luxation of T5–6 was noted. The additional stud-
ies centered on this region showed a malalignment of the seg-
ments plus an increased width of the true vertebral joints
(arrow).
Treatment/Management: Because of the minimal segmen-
tal displacement plus the persistent pain perception, “Kila’s”
fracture was approached with a positive prognosis. The loca-
tion made placement of a vertebral plate difficult and conser-
vative treatment was in the form of a body cast with the dog
positioned beneath a “grate” in a cage that prevented move-
ment. Later radiographs showed the affected vertebra to have
remained in a stable position. The dog was discharged after
four weeks in the clinic.
Thoracic vertebrae 399
4

Case 4.88
4
Noncontrast
Noncontrast Myelogram
Myelogram

Signalment/History: “Romeo” was a 3-year-old, male Toy
Poodle with a history of having been struck by a car four days
previously, resulting in an immediate pelvic limb paralysis.
Physical examination: Deep pain perception was present in
both pelvic limbs. Patellar reflexes were hyperreflexic. The
pannicular reflex was absent caudal to T11–12. Withdrawal
reflexes in the pelvic limbs were normal.
Radiographic procedure: Spinal radiographs and myelogra-
phy were made.
Radiographic diagnosis: On the noncontrast radiographs,
the disc space at T12–13 was narrowed (arrow). The VD my-
elogram showed cord widening with narrowing of the sub-
arachnoid columns. The lateral myelogram showed elevation
of the narrowed ventral subarachnoid column at T12–13.
Differential diagnosis: The radiographic and myelographic
findings were diagnostic of a fracture/luxation with an ex-
tradural lesion on the floor of the spinal canal at T12–13 that
could be protruded disc tissue with or without extradural
hemorrhage. The widened cord suggested minimal cord ede-
ma/hemorrhage as well. Changes of this type are due to the
traumatic spontaneous acute disc protrusion plus the segmen-
tal malalignment at the time of the trauma.
Treatment/Management: The owners chose not to treat
the dog.
Comments: Without the clinical history of trauma, these ra-
diographic and clinical findings could also be found in a pa-
tient with acute disc protrusion.
4

Case 4.89
Signalment/History: “Donner” was a 1-year-old, female
German Shepherd cross with a history of running into a post
and being unable to rise following the injury.
Physical examination: Because of the known trauma, spinal
radiographs were ordered immediately.
Radiographic procedure: Spinal radiographs were made.
Radiographic diagnosis (day 1): A thin fracture line
extended through the arch of T12 into the caudal end plate
separating the arch and a part of the body from the larger
fragment of T12. The fracture line extended craniodorsal
to caudoventral. The larger fragment of T12 was displaced
ventrally. The smaller fragment included the caudal articular
facets. The disc space was narrowed.
Radiographic diagnosis (day 11): Radiographs made 11
days later showed a more complete collapse of the disc space
with a slight ventral displacement of the body of T12.
Treatment/Management: The patient was kept under close
control and the relatively nondisplaced fragments healed in a
satisfactory manner with conservative treatment.
4
Day 1
Day 11

Case 4.90
Signalment/History: A 1-year-old, male mixed-breed dog
had been injured ten days earlier and had remained paraplegic
since that time.
Physical examination: An abnormal malalignment at
T12–13 was palpated. The neurologic examination indicated
an upper motor neuron lesion in the pelvic limbs. Deep pain
could be elicited.
Radiographic procedure: The study was centered at the
thoracolumbar junction with great care being taken in posi-
tioning the dog for the VD view.
Radiographic diagnosis: The body of T12 was collapsed as
seen on both views (large black arrow). The fragment repre-
senting the caudoventral portion of the T12 vertebral body
was displaced to the left and ventrally. A luxation indicated
destruction of the disc and permitted ventral displacement
with lateral angulation of the caudal segments. The dorsal
processes could be identified on the VD view (long thin ar-
rows). On the lateral view, the vertebral malalignment was
identified by noting the displacement of the roof of the spinal
canal (long thin arrows).
Treatment/Management: The owner seemed only inter-
ested in determining the cause of the paraplegia and did not
permit treatment.
4

4
Noncontrast
Myelogram
Intravenous urogram

Case 4.91
Signalment/History: “Tisza” was a 5-year-old, female
Viszla who had been hit by a car 12 hours previously. She had
been treated at an emergency clinic and diagnosed as having a
T12–13 fracture.
Physical examination: Because a pneumothorax caused se-
vere dyspnea, the examination was difficult to perform.
Radiographic procedure: A second series of spinal radio-
graphs were made plus a myelographic study.
Radiographic diagnosis (noncontrast): Disc space nar-
rowing at T12–13 with minimal ventral displacement of the
body of T13 was noted.
Radiographic diagnosis (myelogram): This showed cord
edema/hemorrhage extending the length of one vertebral seg-
ment. An extradural mass was not identified. The lesion was
diagnosed as a fracture/luxation with traumatic disc collapse.
Treatment/Management: The vertebral fracture/luxation
was decompressed and stabilized on the day of admission. The
pneumothorax regressed almost immediately.
Nine days later the dog developed hematuria and radiographs
taken at that time showed the T12–13 lesion to appear un-
changed except for the expected post-surgical changes (white
arrow); however, a distended urinary bladder was evident.
An intravenous urogram showed normal renal function with
multiple filling defects in the bladder suggesting numerous
blood clots. The bladder injury apparently resulted in delayed
renal drainage and bilateral hydroureter was evident. The last
radiographic study was made five months after the injury and
showed that the fracture area had remained stable.
Comments: The absence of an extradural mass on the mye-
logram suggested that the herniating disc “exploded”, with the
disc material spreading along the spinal canal and traumatizing
the cord. Another possibility, more likely in a 5-year-old, was
that the disc had protruded laterally or ventrally and the cord
injury was from being struck by the vertebral segments as they
displaced.
4
9 days later

Case 4.92
4
Noncontrast
Myelogram

Signalment/History: A 5-year-old, male German Shepherd
was thought to have been hit by a car causing an sudden on-
set of pelvic limb paralysis.
Physical examination: Neurologic examination suggested
an upper motor neuron lesion in the pelvic limbs. No
malalignment of vertebral segments could be palpated.
Radiographic procedure: Noncontrast spinal radiographs
plus a myelogram were made.
Radiographic diagnosis: The collapse of the space at
T12–13 was evident with an epidural mass on the floor of the
canal was revealed by the myelogram (arrows).
Comments: In this patient, the nature of the trauma was not
known and may have been something rather benign as could
happen while playing in the garden or as the result of an au-
tomobile accident. The treatment for the epidural mass is the
same regardless of the etiology of the disc protrusion and must
include decompressive surgery.
4

Lumbar vertebrae
Case 4.93
4
Noncontrast
Noncontrast
Myelogram
Myelogram

Signalment/History: “Sandy” was a one-year-old female
Viszla who had been struck by a car several hours earlier. She
had continued walking and then “went down”.
Physical examination: The dog showed a Schiff-Sherring-
ton sign in the forelimbs and had reduced pain perception in
the pelvic limbs. She had no voluntary movement in her pelvic
limbs, but she had normal reflexes in them. The tail was flac-
cid and she had a weak anal sphincter reflex. The reflexes in
the forelimbs were normal.
Radiographic procedure: The radiographs needed to in-
clude the region of the spine where a lesion would result not
only in a cauda equina syndrome but also would cause an up-
per motor neuron lesion in the pelvic limbs. This included the
spine caudal to T2. Myelography was performed.
Radiographic diagnosis (noncontrast): A fracture of the
sacrum with avulsion of the caudal fragment and a soft tissue
mass ventral to the injury were present (arrow); the latter
probably representing a hemorrhage. The remainder of the
spine was thought to be normal on the noncontrast studies.
Radiographic diagnosis (myelogram): Tearing of the
meninges had resulted in a leakage of contrast agent at the site
of the sacral fracture indicating a severe injury (arrow). The
subarachnoid contrast columns showed narrowing from T12
to L3 with an associated narrowing of the spinal cord and a
shift toward the left (arrows).
Differential diagnosis: The thoracolumbar epidural mass
was most likely hemorrhage because of its continuing presence
over five vertebral segments. No narrowing of a disc space or
a focal mass that would indicate the presence of a localized disc
protrusion was evident. Infectious or neoplastic lesions were
not considered in a patient of this age and with this clinical
history.
Treatment/Management: “Sandy” was treated conserva-
tively without improvement and was euthanized following a
lack in improvement in her neurologic status. The body was
taken without permission for a necropsy.
Lumbar vertebrae 409
4

Case 4.94
Signalment/History: This young female cat had been found
by the roadside two weeks previously, but had just been
brought in for examination.
Physical examination: The cat had caudal limb paralysis.
Urinary incontinence was evident.
Radiographic procedure: Noncontrast radiographs were
made of the thoracolumbar spine.
Radiographic diagnosis: A compression fracture involved
the body of L3 and was identified by an inward folding of the
ventral cortex (black arrows). A dense shadow was identified
on the floor of the spinal canal and was thought to be a part of
the trabeculae displaced by the fracture (white arrow). The
distended urinary bladder was evident (arrows).
Differential diagnosis: A compression fracture always sug-
gests a pathologic fracture, therefore the patient’s diet and
blood chemistry should be examined.
4

Case 4.95
Signalment/History: “Cisco” was a 2-year-old, male Irish
Setter who had been in an automobile accident 12 hours pre-
viously.
Physical examination: The dog was unsteady on his pelvic
limbs when walking and was painful as evidenced by his try-
ing to bite during the palpation of his pelvis.
pelvis.
Radiographic diagnosis: Ventral displacement of a caudal
sacral fragment was noted plus a left sacroiliac fracture/luxa-
tion (arrows). Spondylosis deformans was noted at L4–5 and
L6–7. The lumbosacral junction and the hips were normal.
The dense shadow superimposed over the left sacro-iliac junc-
tion was fecal material.
Treatment/Management: Detection of the sacroiliac injury
explained why “Cisco” was so painful, and why he delayed us-
ing his pelvic limbs during the recovery period.
Note the use of the less painful, flexed position of the pelvic
limbs for radiography. The radiolucent shadows seen dorsal to
the right acetabulum on the lateral view represent gas within
the rectum.
4

4

Case 4.96
Signalment/History: “Duchess” was a 6-year-old, female
German Shepherd cross, who had collapsed 12 days previous-
ly and had been treated with steroids resulting in a slight im-
provement. Subsequently, she had another event of pelvic
limb paresis and was referred for radiographic examination of
the spine.
Physical examination: Because of her history, she was
scheduled immediately for spinal radiographs.
Radiographic procedure: Both noncontrast and contrast
studies were made.
Radiographic diagnosis: Severe spondylosis deformans in
the lumbar region with segmental fusion resulted in a hyper-
mobility of the adjacent discs (domino effect). All the studies
showed a misalignment at L1–2, while the myelogram showed
a short cord segment with edema/hemorrhage (white arrows).
A second site of potential cord injury at the LS disc showed
both malalignment and dorsal disc protrusion (black arrows).
Differential diagnosis: The role of trauma in this patient
was difficult to assess. The immobility of the lumbar segments
apparently placed excessive stress on the adjacent discs so that
minimal trauma could have resulted in the cord injury.
Treatment/Management: Decompressive surgery was per-
formed. Because of the unexpectedly soft nature of the disc
material taken from L1–2, surgical biopsy was utilized to con-
firm the presence of degenerated intervertebral disc material.
Histological examination of the material suggested a more
acute disc protrusion as would be associated with trauma.
“Duchess” was discharged with some improvement, but not
totally recovered.
Comments: Spondylosis deformans of this extent with solid
bridging extending over multiple segments is referred to as
Disseminated Idiopathic Skeletal Hyperostosis (DISH) and of-
ten results in patients with a clinical picture such as seen in
“Duchess”.
4

Case 4.97
Signalment/History: “Nebraska” was an 8-month-old, fe-
male Chow Chow who had been run over by her owner’s
truck three days earlier. The left femur was fractured and had
been treated surgically. After the surgery, the dog lost use of
her right pelvic limb and had no reflexes or cutaneous sensa-
tion in that limb. However, the deep pain reflex was still pres-
ent. The dog was referred with a suspected lumbosacral injury
following treatment of the fracture.
Physical examination: Examination was difficult because of
the injuries and the post-surgical status. Radiographs were
made with the intention of performing a myelogram.
Radiographic diagnosis (femur): A single lateral view of
the femur showed the reduction of a comminuted midshaft
fracture by a single IM pin with two cerclage wires positioned
at the fracture site. The proximal fragment was “bayoneted”
into the distal fragment.
Radiographic diagnosis (lumbar spine): A single lateral
view of the lumbar spine was selected from the complete spinal
study. No evidence of abnormality was noted.
4
Femur
Lumbar spine

Radiographic diagnosis (myelogram): The first lateral
view showed the spinal needle in position at L4–5 immedi-
ately after the trial injection. Extradural pooling of the con-
trast was noted around the needle tip along with a filling de-
fect within the dorsal subarachnoid column. The defects in
filling seen around the needle site were not fully appreciated
and the remainder of the contrast agent was injected.
The next film showed thinning of both the dorsal and ventral
subarachnoid columns with continued leakage of contrast
agent into the extradural space. The last lateral film was made
after the subarachnoid pressure had decreased and showed
more contrast agent in the subarachnoid columns over L4–5
(arrows). A continued leakage into the extradural spaces was
also evident. The VD and oblique views showed the same ra-
diographic pattern with collapse of both subarachnoid
columns and leakage into the extradural space on the left.
Treatment/Management: With the history of trauma and
the neurological signs of a lower motor neuron lesion, the di-
agnosis of spinal hemorrhage or contusion with dural tearing
was considered. Examination of the CSF showed an excess of
cells indicating hemorrhage. On the basis of the suspected
spinal cord injury, “Nebraska” was euthanized.
Outcome: Necropsy finding showed severe myelomalacia
from L3–L6 secondary to trauma, with secondary severe Wal-
lerian degeneration from T12–L8. The ventral spinal artery
was thrombosed. All the lesions were more severe on the right.
Comments: Intramedullary swelling with narrowing of the
subarachnoid columns were the primary features. The changes
were noted at the site of the lumbar intumescence, which was
also the site of the needle placement; both of which compro-
mised interpretation of the myelogram.
4
Myelogram

Case 4.98
4
Noncontrast
Myelogram

Signalment/History: “Sundance” was a 5-year-old, male
Doberman Pinscher with a sudden onset of caudal paresis
thought to have been induced by trauma.
Physical examination: The neurological examination
showed upper motor neuron signs in the pelvic limbs with
crepitus palpated in the upper lumbar spine.
Radiographic procedure: Noncontrast spinal radiographs
were made, followed by myelography.
Radiographic diagnosis (noncontrast): Collapse of the
L1–2 disc space was present with some sclerosis of the end-
plates and a large bony osteophyte ventrally. On the VD view,
the collapse at L1–2 was associated with a lateral displacement
of L2 to the right with some rotation to the left (arrows).
Spondylosis deformans was prominent at L3–4; however, that
disc space appeared to be of normal width.
Hypoplasia of the ribs could be seen in the last thoracic seg-
ment. This is a form of transitional vertebral segment.
Radiographic diagnosis (myelogram): The elevation and
slight shifting toward the left side of the spinal cord, and the
mild narrowing of the subarachnoid columns were diagnostic
of an extradural mass on the floor of the canal just over the
disc space with minimal injury to the spinal cord (arrows).
The diagnosis was a traumatic protrusion of the degenerating
disc at L1–2.
Differential diagnosis: Malalignment of vertebral segments
is an important radiographic feature. In the absence of such a
malalignment, the radiographic features seen in this case were
those frequently seen with chronic disc degeneration. The
identification of the malalignment is more supportive of a
change following trauma. Myelography was necessary to con-
firm that the trauma had played a role in the malalignment of
the L1–2 segments.
Treatment/Management: Because of the minimal size of
the extradural mass, “Sundance” was treated conservatively
with strict cage rest. He recovered and was discharged after
several weeks in the clinic.
Comments: A point of potential error in this patient was in
the description of the location of the trauma. The presence of
the hypoplastic ribs on the last thoracic segment made for a
difficult determination of where the first lumbar segment was
actually located.
4

4.2.2.4 Malunion fractures
Malunion is the joining together of fracture fragments that re-
sults in an abnormal bone organ, which is unacceptable to the
patient and/or the owner because of: (1) bone shortening due
to fragment over-riding, (2) angulation of the distal fragment,
(3) rotation of the distal fragment, or (4) osteosynthesis be-
tween adjacent bones. The pattern of fracture healing is nor-
mal and a histological examination of the bridging callus or the
resulting remodeled bone is normal. Only the gross bone or-
gan is abnormal and the manner in which the limb functions
is often unacceptable (Table 4.13).
Table 4.13: Radiographic signs of malunion fractures
1. Pattern of malunion
a. overriding fragments with shortening of the bone
b. fragment malalignment
I. cranial or caudal angulation
II. lateral or medial angulation
III. rotational malalignment
c. osteosynthesis with adjacent bone formation
d. secondary to osteomyelitis
2. Secondary to gunshot fracture
3. Malunion resulting from fracture causing physeal growth anomaly
a. delayed growth
b. partial closure with angulation
c. complete closure with shortening
Any fracture can heal as a malunion. The interpretation is
based only on the bone having a morphology, in the eyes of
the observer, other than that seen normally. The degree of ab-
normality can be extensive or minimal, and an evaluation must
be made to determine its clinical importance. For example,
minimal over-riding of fragments in the midshaft of the femur
without rotation or angulation causes bone shortening that can
be compensated for easily. However, if the same fracture heals
with rotation, the stability of the hip joint may be affected and
the femoral head may subluxate due to the resulting antever-
sion of the femoral head and neck, or the limb is used in an in-
ternal rotation position with resulting injury to the stifle joint.
Any fracture that is articular and heals with malunion will re-
sult in secondary arthrosis and will be clinically important.
Physeal fractures that cause unequal growth, delayed growth,
or premature closure can also be considered malunion. They
are, however, treated separately in this book (Chap. 4.2.2.6).
4

Case 4.99
Signalment/History: “Skooter” was an 8-month-old, male
Brittany with a history of having been struck by a car two
months earlier. He had been limping on the right pelvic limb
since that time.
Physical examination: Pain was elicited on palpation of the
right hip joint. Muscle atrophy was marked. The hip palpated
as though the femoral head was luxated.
Radiographic procedure: A VD radiograph of the pelvis
was made in addition to a lateral view of the femur.
Radiographic diagnosis: A chronic malunion fracture of
the right acetabulum was present, characterized by a marked
medial displacement of the bony fragments causing a narrow-
ing of the pelvic canal. The size and shape of the femoral head
were preserved but the head fitted poorly into the malformed
acetabulum. Radiographic signs of the secondary post-trau-
matic arthrosis were not as prominent as might have been ex-
pected.
Treatment/Management: No treatment was considered.
The owner was advised of the possible continuing problems
associated with progressive arthrosis and the problems associ-
ated with normal defecation that might result from the pelvic
narrowing.
Comments: The fracture line had entered the acetabulum in
such a manner that the important weight-bearing portion of
the acetabular roof (cranial and dorsal) remained uninjured.
The femoral head, therefore, was able to continue to articulate
with the rather large and important portion of the articular
surface that remained uninjured.
Malunion fractures 419
4

Case 4.100
Signalment/History: “Skipper” was a mature Cocker
Spaniel with a history of forelimb injury seven years previous-
ly. The owners did not have an accurate memory of the na-
ture of the injury, but thought that he had fractured his radius
and ulna and some type of surgical repair had been utilized.
They had brought “Skipper” to the clinic because they could
feel something in his “skin” and because he had become slight-
ly lame on this limb.
Physical examination: The patient was sensitive to deep
palpation and a firm mass could be palpated cranially just dis-
tal to the elbow joint. Motion of the antebrachiocarpal joint
and rotation of the foot was limited. The use of the limb was
also limited and the dog seemed to use it hesitantly.
Early radiographs: The original radiographs were obtained
from another clinic and revealed the original premature clo-
sure of the distal ulna and the surgical repair.
Radiographic procedure: Two views of the forelimb were
made on the day of presentation to evaluate the soft tissue
mass.
Radiographic diagnosis: Osteosynthesis between the radius
and proximal ulnar fragment was identified with an in-
tramedullary pin remaining partially within the distal radius.
The proximal tip of the pin extended through the cortex into
the soft tissue by a distance of 1 cm. The alignment of the ra-
dial fragments was near anatomical.
Treatment/Management: The treatment recommended
was only symptomatic because of the chronicity of the arthro-
sis, the limited nature of the lameness, and the older age of the
dog. However, the owner was “unhappy” with the protrud-
ing pin and asked for its removal. This was done without in-
cidence and “Skipper” was discharged a happy dog, although
there was little improvement in his gait.
Differential diagnosis: Any bone or joint disease could have
caused the signs evident in this dog. The role of the IM pin
was suspect even though there were no clinical or radiograph-
ic signs of associated infection. Secondary joint disease in the
antebrachiocarpal joint was high on the list because of the his-
tory of earlier trauma and because of the dog’s age. As the
Cocker Spaniel is not a breed which is highly susceptible to
malignant bone or joint disease, and does not regularly have
osteochondrosis/osteochondritis dissecans, these diagnoses
were positioned lower on the differential list. Any soft tissue
4
Early radiographs Day of presentation

lesion could have been a cause of the lameness. An inflamma-
tory lesion could have been considered although no history of
a bite wound or draining tract was offered.
Second presentation
Signalment/History: “Skipper” was presented 24 months
later with a more acute lameness and a large swelling on the
distal antebrachial region that was obvious to the owner and
was thought to have formed within the previous two weeks.
Physical examination: A firm mass was palpated on the
distal limb with the majority of the mass lying cranial and
lateral. Pain was elicited on firm palpation. Movement of the
distal joints was limited partially because of the mass, partially
because of chronic arthrosis, and partially because of pain.
Differential diagnosis: The suddenly presenting mass was
suggestive of a malignant process and this was first on the list
of differential diagnoses. The absence of any history of recent
trauma tended to exclude a fracture/luxation or an infection
following an injury.
tal limb centering on the mass.
Radiographic diagnosis: A highly productive bony lesion
originated from the distal radius, where a radiolucent center
approximately 1–2 cm in diameter was located. The periosteal
new bone was rather well formed and had a sharp border. The
new bone effectively covered the distal tip of the ulna making
any determination of the degree of involvement of that bone
by the lesion difficult. The soft tissue mass extended around
the new bone. Involvement of the radial carpal bone was pos-
sible, although the new bone created a cuff that extended dis-
tally, covering the carpus, and preventing the exact determi-
nation of progression distally. It almost appeared that the bony
lesion “grew” along the new bone that formed the osteosyn-
thesis between the radius and ulna. The zone of transition be-
tween the lesion and normal bone was indistinct and rather
long.
The diagnosis reached was that of a primary bone tumor,
probably osteosarcoma, following malignant transformation at
an old fracture site.
Treatment/Management: Because of the older age of the
dog and the presence of a suspect malignant process, “Skip-
per” was euthanized.
The necropsy finding was that of an osteosarcoma. No spread
of the malignancy was noted in the lungs.
Comments: Malignant transformation following a fracture
often follows an incorrectly utilized metallic implant or a
chronic, concurrent inflammatory process. In this patient, the
fracture treatment appeared satisfactory and without any his-
tory of a persistent inflammatory process, with the exception
of the protruding tip of the IM pin proximally. It is also pos-
sible that the primary bone tumor occurred unrelated to the
earlier fracture or surgery. However, this breed has a low fre-
quency of primary bone tumor making a malignant transfor-
mation at the surgical site more likely.
4
24 months later

Case 4.101
Signalment/History: “Smokey” was the name given to a
young male cat who had been brought to the clinic as a
“stray”. He was lame, but the nature of any trauma was un-
known.
Physical examination: The left hip joint palpated abnor-
mally and a fracture was evident in the left distal tibia with se-
vere soft tissue swelling.
distal limb.
Radiographic diagnosis: The distal tibial fracture was bad-
ly comminuted with rather large butterfly fragments. A single
fracture of the fibula was present. The fragments were im-
pacted and the soft tissue injury was thought to be severe.
Joint disease at the antebrachiocarpal and intercarpal joints was
characterized by subchondral bone cysts and periosteal new
boneespeciallyontheaccessorycarpalbone.Cranialrotationof
the distal radial fragment had altered the plane of the articular
surfaces of that joint contributing to the secondary arthrosis.
The elbow joint was radiographically normal. The soft tissues
were thought to be unremarkable
Differential diagnosis: The cause of the trauma was un-
known, if it were due to a bite wound, the possibility of sec-
ondary infection would have been considered likely.
Treatment/Management: The tibial fracture was treated
with a full Kirschner apparatus (Type II splintage). Healing of
the tibial fracture was delayed and a cancellous graft was added
after two months.
Radiographs made at three months showed the Kirschner ap-
paratus to still be in place. A small strip of bone joined the two
major tibial fragments (white arrows). Another pointed
“peak” of new bone extended from the distal fragment, but
had failed to meet the proximal fragment (black arrows). The
fibula had healed with a rather strong appearing union. Both
stifle and tarsal joints were still normal in appearance. The
tibial malunion was weak and resulted in the problem of
deciding how to stage the removal of the external apparatus to
permit further strengthening of the healing callus without
overstressing it and causing a pathologic fracture.
4

Case 4.102
Signalment/History: “Yamo”
was a 4-year-old, male German
Shepherd mixed breed with a histo-
ry of lower bowel obstruction. He
had been straining to defecate over
the previous three days.
Physical examination: The dog
was depressed and appeared to be
uncomfortable. A large firm tubular
mass was palpated in the abdomen.
Radiographic procedure: Ab-
dominal studies were made includ-
ing the pelvic region.
Radiographic diagnosis: A dis-
tended colon with an apparent con-
striction cranial to the pelvis was
filled with inspisated fecal material. A soft tissue mass was po-
sitioned between the pelvic rim and the distended colon, and
probably represented the prostate gland. The urinary bladder
could not be identified.
The badly deformed left hemipelvis resulted in at least a 50%
occlusion of the pelvic inlet. The left femoral head was seated
within the malformed acetabulum. A small surgical plate was
positioned on the acetabular margin. The small pin in the
greater trochanter probably indicated the site of a trochanteric
osteotomy. The malformed body of L7 and the heavy spondy-
losis deformans suggested a malunion fracture in this region.
Treatment/Management: Multiple enemas were adminis-
tered and resulted in two small “onions” being retrieved in ad-
dition to the hard fecal material.
Comments: Later, the owner offered the history that
“Yamo” had been struck by a car as a puppy and had had a sur-
gically corrected pelvic fracture. They had not been informed
of the LS fracture.
4

Case 4.103
4

Signalment/History: “Rose” was a 1-year-old, female kit-
ten who had been found by the owner three weeks previous-
ly. She had been brought to the clinic because the owners
thought she was pregnant and in labor. No kittens had been
born.
Physical examination: Palpation of the abdomen suggested
a gravid uterus and the cat was straining as though in labor.
abdomen and pelvis.
Radiographic diagnosis: Abdominal radiographs showed
the gravid uterus with four fully developed fetal skeletons. No
abnormal gas accumulation was associated with the skeletons
and there was no collapse of the skeletal structures suggesting
that the feti were dead.
Malunion fractures of the left ilium and ischium had resulted
in the destruction of the acetabulum and a narrowing of the
pelvic inlet. A chronic subcapital non-union epiphyseal frac-
ture had lead to a dorsal luxation of the left femoral head. The
right femur had a malunion fracture distally resulting in short-
ening of the bone. The right femoral head was normal and was
seated within the acetabulum.
Treatment/Management: The kittens were removed by
cesarean section some days after the radiographic examination
and were all dead. The surgical incision became infected and
because she had been a stray, the owners elected not to con-
tinue treatment but to have the cat euthanized. At necropsy,
the vaginal stump of the uterus was infected along with the su-
ture line.
Comments: The determination of fetal death on a radio-
graphic study is only accurate after fluid absorption has result-
ed in collapse of the skeletal structures or if gas accumulation
has occurred within the fetus. Ultrasound examination is the
technique of choice in evaluation of fetal viability.
4

Case 4.104
Signalment/History: A mature female German Shepherd
was found and brought to the clinic because of an obvious me-
chanical lameness in the left pelvic limb.
Physical examination: Shortening of the limb plus the de-
tection of a large firm mass around the midshaft of the femur
suggested a healing fracture or a malunion fracture. The lesion
was not painful tending to rule out an infectious or malignant
lesion.
pelvis and both femurs.
Radiographic diagnosis: On the left, there was a chronic,
comminuted, oblique midshaft femoral fracture in a healing
phase, with marked separation and over-riding of the frag-
ments. A massive exuberant callus had started to bridge be-
tween the two bones. The stifle joint appeared normal; how-
ever, the proximal fragment had assumed an anteversion
position and caused a partial luxation of the femoral head
(arrow). The fracture had the appearance of being more than
one month old. Soft tissue atrophy around the affected limb
was prominent.
4
On presentation

Treatment/Management: The dog was treated conserva-
tively. Radiographs made two months later showed healing of
the fracture with apposition and alignment of the fragments
remaining unchanged. Note the femoral head appeared to be
seated deeply, the result of the limb being in partial abduction.
Comments: Often it is important to determine the age of an
injury to assist in the determination of treatment. In this dog,
the fracture callus and modeling of the fragments suggested a
stage of healing that would have made it nearly impossible to
attempt a repositioning of the fracture fragments. The possi-
bility of injury to tendon, ligament, or nerve was described to
the owner in an explanation of the problems that the dog
might have in walking. Note the transitional lumbosacral seg-
ment, which is a common congenital anomaly in this breed.
It is more accurate to measure the length of the femur on the
lateral view, because it is parallel to the tabletop, than on the
VD view in which position the femur may be at an angle to
the surface.
4
2 months later

Case 4.105
Signalment/History: “Gray Ling Cry” was an adult male
cat with a history of a slight lameness in the left pelvic limb.
The owners wanted to know more about the injury and its
clinical importance.
Physical examination: The cat could walk on the affected
limb suggesting a mechanical lameness rather than a lameness
due to pain. A comparison of the length of the pelvic limbs in-
dicated that the shortening of the left limb was indicative of a
dorsocranial coxofemoral luxation. Movement of that limb
produced marked crepitus. Soft tissue atrophy was slight.
pelvis and hip joints.
Radiographic diagnosis: While the lateral radiograph of the
pelvis was relatively normal in appearance, the VD view
showed an extensive pseudoarthrosis of the left coxofemoral
joint. The new acetabular roof extending from the ilium was
very prominent. The acetabulum was shallow with the ap-
pearance that the dorsocranial acetabular margin had fractured
free. The femoral head and neck were severely deformed sug-
gesting that the capital epiphysis had fractured free and had
subsequently undergone a malunion healing to the femoral
neck. The free bony fragment adjacent to the bony spur at-
tached to the right ilium was probably an avulsion from the
greater trochanter. The right hip joint was normal.
Outcome: The owners chose not to consider a femoral head
and neck ostectomy that was offered as a way to diminish the
lameness and pain.
Comments: The exact explanation of the nature of the orig-
inal trauma was an academic exercise that played only a minor
role in either the clinical condition of the patient at the time
of presentation in this case or the expected prognosis. The le-
sion is definitely post-traumatic with formation of a
pseudoarthrosis following injury to the left hip joint.
4

Case 4.106
Signalment/History: “Rhonda” was a 2-year-old, female
German Shepherd undergoing routine radiographs of the
pelvis to determine the status of her hip joints. She had no his-
tory of injury or lameness.
Radiographic procedure: Routine VD studies were made
of the pelvis for a hip dysplasia study.
Radiographic diagnosis: Both hip joints were radiographi-
cally normal with the femoral heads well formed and seated
deeply in well-formed acetabula. A bony lesion involved the
ischiatic tuberosity of the right ischium was characterized by a
loss of the normal trabecular pattern, a displaced cortical seg-
ment, and an area of increased bone density.
Differential diagnosis: The dog was young and had no his-
tory of trauma. The diagnosis of a malunion/non-union frac-
ture was considered first as a bone tumor or an osteomyelitis
would have been associated with more reactive bone and
would be more painful. Also, this lesion had a smooth border
which suggested a chronic benign process.
Treatment/Management: Palpation of the tuberosity failed
to produce any pain or discomfort and the lesion was not
treated.
Comments: The discovery of what is assumed to be a chron-
ic traumatic event is rather common in skeletal radiography.
Often the finding is of no clinical importance, but in some pa-
tients it explains chronic lameness or may suggest the possibil-
ity of future clinical importance.
4

Signalment/History: “Freta” was a 5-year-old, female Ger-
man Shepherd mixed breed who was presented with muscle
atrophy in the left pelvic limb.
Physical examination: The left limb lameness was more
mechanical than painful. The stifle joint was enlarged but was
non-painful and firm on palpation. The right tibia was thick-
ened and deformed with a valgus deformity and slight caudal
angulation.
Radiographic procedures: Studies were made of the pelvis
and right pelvic limb.
Radiographic diagnosis (pelvis): A malunion left acetabu-
lar fracture, malunion pelvic fractures of the left ischium and
ilium, and a post-traumatic fusion following a luxated right
sacroiliac joint were noted. The severity of the post-traumat-
ic arthrosis in the left hip joint was difficult to determine. The
subluxation of the right femoral head could have been sec-
ondary to hip dysplasia or influenced by the malposition of the
pelvis following the trauma. Generalized muscle atrophy was
more pronounced on the right.
4
Case 4.107

Radiographic diagnosis (tibia): A malunion fracture in the
midshaft of the right tibia had resulted in a nonanatomic
restoration with caudal and lateral angulation of the distal tibia
resulting in a valgus deformity. Osteosynthesis of tibia and
fibula had occurred. The persistent cavitary pattern (arrows) at
the site of malunion suggested a chronic bone infection,
whose state of activity could not be determined on the radio-
graphs.
The post-traumatic joint disease in the stifle and tibiotarsal
joints was important clinically.
Comments: What was rather confusing on physical exami-
nation became apparent through the radiographic studies. The
biggest question as to the continued use of the left limb was
the degree of severity of the arthrosis in the left hip joint and
what was the resulting limitation of movement of the pelvic
limb. The contour of the femoral head appeared near normal
suggesting that a femoral head or neck fracture was not a part
of the injury. The question of why the muscle atrophy was
more prominent on the right was answered by evaluation of
the radiographs of the right tibia. The nature of that malunion
fracture was influenced by the presence of chronic os-
teomyelitis. The original radiographs did not clearly show the
severity of the joint injuries, which were possibly a major
cause of the dog’s inability to use its limbs normally at the time
of examination. A lateral malleolar fracture was suggested as
well.
This was a difficult case, since the original injuries involved
the left hip joint, the right stifle joint, and the right tibiotarsal
joint. The joint injuries had a greater clinical importance at
presentation than the malunion pelvic and tibial fractures. Su-
perimposed on these injuries was the suspected chronic bone
infection in the tibia.
4

Case 4.108
4
Pelvis
Barium enema

Signalment/History: “Sable” was a 10-year-old, male Col-
lie with a history of chronic diarrhea and a report by the own-
er that he had not eaten for eight weeks.
Physical examination: “Sable” was thin, but had probably
been eating some food during the previous couple of weeks.
He was dyspneic, dehydrated, and attempted to vomit during
the examination. He had a palpable deformity in the right
hind limb, which also had limited motion and marked muscle
atrophy. In addition, there was an inguinal hernia on the right
side
Radiographic procedure: A single lateral view was made of
the pelvis because of difficulty in positioning the dog due to
the deformity of the right hindleg. This was followed by a low
barium enema and a second lateral radiograph was made. Be-
cause of the dyspnea and attempts at vomiting, a single lateral
radiograph of the body was made.
Radiographic diagnosis (pelvis): A malunion midshaft
fracture of the right femur had resulted in a cranial displace-
ment of the proximal fragment and an anteversion of the
femoral head. Subluxation of the femoral head was noted. In
addition, a 4- to 5-cm circular mass containing material re-
sembling impacted feces was located on the floor of the pelvic
inlet. A second circular mass was located dorsal to the os pe-
nis. The ventral abdominal wall could not be seen at its at-
tachment to the pelvis.
Radiographic diagnosis (barium enema): The rectum
was displaced dorsal to the mass. The mass was thought to re-
present inspisated feces or a calcified hematoma.
Radiographic diagnosis (body): A cranial malposition of
the gastric air bubble (arrows) and a pleural density that repre-
sented fluid and probably an abdominal organ herniation
could be seen. The cardiac silhouette and the ventral dia-
phragm were not identified. Healed fractures of the 6th–8th
ribs were noted.
Treatment/Management: The diagnosis was that of: (1)
malunion fractures with a probable rectal diverticulum or cal-
cified hematoma, (2) an inguinal hernia that contained the
urinary bladder, and (3) a diaphragmatic hernia.
The owners were questioned further concerning the clinical
history of the dog and admitted that “Sable” had been struck by
a car two years earlier, had been chronically lame since that
time, and was presumed to have had a fractured femur. Because
of the poor condition of the dog, the owners chose euthanasia.
At necropsy, a centrally placed diaphragmatic hernia was not-
ed associated with a cranial displacement of the liver lobes.
The urinary bladder was positioned laterally in an inguinal
hernia. The rectal diverticulum contained inspisated fecal ma-
terial. The malunion fracture of the right femur was as seen on
the radiograph. An unsuspected finding at necropsy was that
of a generalized mesothelioma present on the pleural and peri-
toneal surfaces.
4
Body

Case 4.109
Signalment/History: “Rusty” was a 9-month-old, male
kitten with a history of being struck by a car three weeks pre-
viously. He had been dysuric and hematuric at that time. At
presentation, he was lame in the right pelvic limb.
Physical examination: Crepitus was palpated on movement
of the right hip joint. Motion of that limb was limited. Palpa-
tion of the abdomen demonstrated a large tubular mass occu-
pying most of the abdominal cavity.
pelvis and also of the abdomen because of the unexpected
findings on palpation.
Radiographic diagnosis (abdomen): The colon was
markedly distended and filled with dense fecal material. A
large diverticulum projected ventrally just proximal to the
pelvic inlet. A hernia in the abdominal wall was present, ap-
parently associated with a tear of the prepubic tendon. No
bowel loops were seen within the hernial sac. The urinary
bladder was in its normal position.
4

Radiographic diagnosis (pelvis): A malunion fracture of
the right ilium was most prominent. The pubic and ischial
fractures were located near the symphysis and were seen in a
non-union state. A subcapital femoral epiphyseal fracture had
resulted in resorption of the femoral neck. The capital epi-
physis remained within the acetabulum and had a normal bone
density.
Treatment/Management: The owner was not interested in
spending any money on corrective surgery and was advised to
use enemas and strictly control the kitten’s diet to control the
fecal impaction.
Comments: Hemoclips were evident within the abdomen
and are probably associated with earlier surgery. In a young
patient, such a finding would suggest the necessity of reasses-
sing the reported sex of the kitten.
4

Case 4.110
Signalment/History: “Katie”, a 8-month-old, female Col-
lie, was presented with a badly malformed left pelvic limb. An
injury had occurred when she was four months of age.
Physical examination: The bony abnormalities in the limb
were easily palpated. The foot was rotated laterally. Both the
stifle and talocrural joints had limited movement.
Radiographic procedure: The distal portion of the pelvic
limb was radiographed.
Radiographic diagnosis:Malunion fractures of the tibia and
fibula with cross-healing between these bones and lateral ro-
tation of the distal fragments were noted. Just as important was
the injury to the talocrural joint with crushing of the 4th tarsal
bone resulting in the lateral rotation of the foot. The inter-
tarsal joints appeared to be ankylosed (arrow).
Treatment/Management: No treatment could be offered.
4

Case 4.111
Signalment/History: “Barney” was a 2-year-old, male
Springer Spaniel with a history of injury to the right tarsus six
months previously. The pelvic limb had been placed in a plas-
ter cast at that time. The cast was removed and the owner was
interested in an evaluation of his using “Barney” as a field tri-
al dog.
Physical examination: Firm swelling was palpated around
the tarsus. No pain was evident. Motion of the tibiotarsal and
intertarsal joints was thought to be limited.
Radiographic procedure: Multiple studies were made of
the tarsus.
Radiographic diagnosis: A fracture-luxation at the tibio-
tarsal joint had resulted in a non-union fracture of the medial
malleolus (white arrow). In addition, a displaced osteochon-
dritis dissecans fragment was positioned just medial to the
malleolus (black arrow). A stress radiograph suggested minimal
joint instability. Soft tissue swelling was evident.
Treatment/Management: The owner was advised of the
non-union status of the fracture plus the possibility that the
dog had an osteochondritis dissecans lesion as well. The injury
to the joint plus the resulting instability indicated that “Bar-
ney” would not be able to tolerate heavy athletic activity.
Comments: Two concurrent but different etiologies are not
common, but must be considered. The combined effect makes
the joint injury more important clinically. The diagnosis of a
developmental lesion that is inheritable may be of interest to
the owner.
4

Case 4.112
Signalment/History: “Fin” was a 2-year-old, male German
Shepherd mixed breed, who had been hit by a car one month
previously. A right ilial fracture was stabilized at that time. He
was presented because of persistent diarrhea associated with
straining. The question was whether or not the trauma had
caused some injury to the colon.
Physical examination: The pelvic canal was narrow and the
rectum was distended and filled with soft feces. Proctoscopy
indicated a possible colonic stricture 9 cm cranial to the anus.
Ultrasound examination was not helpful in the diagnosis.
Radiographic procedure: Studies of the pelvis were made,
including a barium enema to evaluate the pelvic soft tissues.
Radiographic diagnosis (noncontrast): The right
hemipelvis was displaced cranially and medially with healing
malunion fractures of the right ilium and pubis. Three wire
sutures held the iliac fragments in position. The hip joints
were unaffected by the trauma. A soft tissue pelvic mass was
thought to represent the clinically detected distended in-
trapelvic rectum. A second soft tissue mass was located just
cranial to the pelvic inlet. A third structure was filled with gas
and probably represented a distended descending colon.
4
Noncontrast

Radiographic diagnosis (barium enema): The contrast
agent mixed with feces in a 6-cm-long, distended rectal seg-
ment. The barium sulfate flowed cranially and ventrally in a
narrow stream (arrow). The contrast agent remained within
the bowel and was not thought to be peritoneal. The cause for
the redundant and strictured intrapelvic portion of the rectum
could not be determined.
Treatment/Management: Surgical exploration located a
surgical sponge just cranial to the pelvic inlet with massive ad-
hesions that had caused the stricture of the colon and resulting
dilatation. Some improvement was noted in the ease of defe-
cation following the surgery; however, the narrowing of the
pelvic inlet remained, and both the soft tissue and bony stric-
tures caused continued chronic problems.
4
Barium enema

4.2.2.5 Non-union or delayed union fractures
The determination of a non-union fracture in its early stages
is a subjective evaluation. The surgeon would prefer to recog-
nize this type of fracture as one requiring only a longer peri-
od for healing and would suggest that “a non-union fracture is
one evaluated by an overly anxious radiologist”. At a later
stage of fracture healing, it is then possible to be specific about
the absence of any healing activity at the fracture site and the
presence of a non-union situation (Table 4.14).
One particular form of fracture healing is difficult to judge:
the healing of a physeal or apophyseal fracture in which a large
component of the tissue around the fracture site is cartilage. In
general fracture healing, the identification of bony callus for-
mation is the radiographic sign that is used to judge the stage
and rate of healing. However, if a physeal fracture is to heal
and the cartilage growth plate activity preserved, a healing cal-
lus should not be seen, especially not a bridging callus. For, if
it is identified, it means that bony tissue is bridging the growth
plate and further growth will be prevented from occurring.
Healing of an apophyseal avulsion fracture is a different mat-
ter clinically, since the length of the bone is not dependent on
the apophysis. Bony union when it occurs, unites the apophy-
seal center to the parent bone providing an attachment for a
muscle, ligament, or tendon.
Delayed healing is seen with unstable fixation, but can also be
seen in the older patient in which the stability of the fracture
is good. The decision of what to do with a case of delayed
healing is usually answered by the particular conditions of the
fracture. If the fragments appear to remain in good apposition
and alignment, there may be no problem in waiting another
four weeks before making a definite decision concerning the
healing.
Non-union is usually recognized when there is no evidence
radiographically of any activity at the fracture site and is char-
acterized by: (1) smooth fragment cortices, (2) uniform frag-
ment density, (3) no periosteal new bone with roughened
margins, (4) callus with a uniform density, (5) smooth callus
margins, and (6) no “fluffy” or early callus formation. It looks
like “nothing is happening” at the fracture site.
Two forms of non-union are recognized. One is the hyper-
trophic form indicating that a reasonable blood supply to the
fracture site was present, while stabilization of the fracture
fragments was probably lacking. The ends of the fragments
tend to form “knob-like” endings or those with a flattened
surface. These patterns may be described as those acquired in
the development of a pseudoarthrosis. Any active fracture
healing may cease before formation of the pseudoarthrosis, in
which case, the activity centering around the fracture site ap-
pears to have “been turned off” and no signs of additional
bridging callus formation are present. Actually, the early callus
of woven bone that has formed becomes smooth as it matures
and the borders of the existing callus become sharp and are
clearly identifiable when compared with the less dense imma-
ture callus in an active healing environment. The medullary
cavity at the end of the fragment tends to fill with bony tissue
creating a rounded appearance called an “elephant foot”, be-
cause of the expanded appearance of the bone end. Remodel-
ing activity takes over until the ends of the fragments have be-
come shaped so that they are lying “comfortably” adjacent to
each other, at which time activity stops and the pseudoarthro-
sis has formed.
The other form of non-union is one of atrophy in which the
fragments become osteopenic and assume a tapered appear-
ance referred to as “penciling”. It seems this is more com-
monly seen in the smaller dog breeds, perhaps because of the
limited blood supply from the soft tissues in the distal portion
of their limbs.
It is possible to have features of hypertrophic non-union in
concert with those of atrophic non-union. This is especially
possible in the event of fractures of paired bones, i.e. the ra-
dius and ulna. The proximal fragments atrophy and taper,
while the distal fragments form a “cup” in which the proximal
fragment sits and the pseudoarthrosis develops.
A third form of non-union is one that is seen in fracture heal-
ing influenced by osteomyelitis. The centrally located infec-
tion causes the callus to widely bridge the infected fracture
site. If the external blood supply is adequate, this type of frac-
ture will eventually heal, assuming more the characteristics of
a malunion.
Table 4.14: Radiographic signs of non-union or delayed union
1. Features of delayed union
a. callus formation is
I. absent
II. minimal
III. delayed
b. fragments
I. fail to lose bone density
II. fail to show any new bone production
c. fixation device permits motion
d. osteomyelitis present at fracture site
I. callus attempts to bridge infected site
II. callus attempts to bridge sequestra
2. Features of non-union
a. atrophic type
I. penciling of fragment ends
II. loss of bone density
III. absence of callus formation
b. hypertrophic type
I. no bridging callus
II. modeling of fragment ends
i) “elephant foot” formation
ii) pseudoarthrosis formation
c. associated with osteomyelitis
I. callus attempts to bridge infected site
II. sequestra influence callus formation
4

Signalment/History: “Brandy” was a 6-month-old, female
German Shepherd cross, who was noted to be limping on the
right pelvic limb. She had shown signs of pain several weeks
earlier and had sat down and cried.
Physical examination: Examination showed a happy, active
puppy who ran around the examination room; however, she
had a shortened right pelvic limb.
Radiographic procedure: Two views were made of the af-
fected limb and only a lateral view was made of the opposite
limb.
Case 4.113
Radiographic diagnosis (lateral views only): A general-
ized cortical thickening was noted in the mid shaft of the right
tibia at the site of cranial angulation of the distal fragment. The
thickening was more prominent cranially and laterally (ar-
rows). The medullary cavity was normal in appearance. A
comparison was made with the normal limb and it was noted
that the left tibia was longer and did not have the pattern of
cortical thickness in its midshaft.
Comments: The radiographic changes were diagnostic of a
fracture undergoing healing at the junction of the proximal
and middle thirds of the tibia. The healed bone was shorter
than the opposite tibia. The physeal growth plates remained
open in both limbs suggesting that the shortening was the ef-
fect of injury to a growth plate with only a delay in growth or
due to over-riding of the fracture fragments. Because the frac-
ture had not been treated, it is difficult to think that the frac-
ture had been complete with over-riding fragments.
Non-union or delayed union fractures 441
4

Case 4.114
Signalment/History: “Barbara” was a 7-year-old, female
German Shepherd mixed breed with a history of trauma to the
right forelimb three months previously. The fractures in the
right forelimb had been treated by casting. The cast had been
changed twice, but the limb had not been radiographed.
Physical examination: The cast was removed to permit ex-
amination. The foot had cranial and medial angulation with
movement felt with palpation at the suspected fracture site.
Pain was not evident. Soft tissue atrophy was present.
Radiographic procedure: Two views of the traumatized
limb were made.
Radiographic diagnosis: A non-union fracture of the distal
radius and ulna was characterized by atrophic changes (pencil-
ing) of the fragment ends. An effort to form a pseudoarthrosis
between the overlapping radial fragments was evident.
Marked disuse osteopenia was evident in the distal fragments.
The elbow joint appeared normal and the distal joints ap-
peared to not have been affected by the trauma.
Note the more prominent disuse osteoporosis in the distal
fragments. A pattern of soft tissue density remained in the
carpal area following removal of the cast.
Treatment/Management: The owner was informed about
the possibilities of attempting to surgically correct the non-
union fractures. “Barbara” was lost to follow-up.
4

Case 4.115
Signalment/History: “Deacon” was a 12-year-old, male
German Shepherd cross with a history of lower limb amputa-
tion of the right pelvic limb nine years earlier. The skin over-
lying the stump had begun to dry and develop cracks with
drainage tracts.
Physical examination: The amputation stump was swollen
and warm with a question of soft tissue infection and/or os-
teomyelitis.
Radiographic procedure: The remainder of the right limb
was radiographed.
Radiographic diagnosis: Bone atrophy was evident with
penciling. The cortices were thin. No reactive bone was not-
ed. The pattern seen was thought to be due to disuse and as
expected. The absence of any periosteal new bone or destruc-
tive pattern suggested the absence of osteomyelitis or any sec-
ondary malignant process. A fistulous tract was seen (arrow).
Differential diagnosis: Normal bone atrophy was seen
without evidence of underlying bone disease.
Treatment/Management: Drainage was established and the
patient treated with antibiotics.
Comments: An understanding of the radiographic features of
non-weightbearing or disuse of a limb is important to prevent
the overdiagnosis of a destructive bone lesion from another
etiology. Also, the presence of disuse osteopenia helps in the
estimation of the duration of time since a traumatic event or
the duration of disuse.
4

Case 4.116
Signalment/History: “Re-Wrap” was a 14-month-old, fe-
male Labrador Retriever with a history of a fracture six weeks
previously. Since that time the pelvic limb had remained in a
cast and the dog had not supported weight on the limb.
Physical examination: The cast was removed. A firm, non-
painful thickening of the soft tissues was evident around the
lower limb. No draining tracts were present and the limb was
not hot. Movement of the foot failed to cause motion at the
suspected site of fracture. The affected limb was shorter when
compared with the opposite limb.
Radiographic procedure: Studies of the lower limb were
made.
Radiographic diagnosis: A healing comminuted fracture,
which was evident in the proximal one-half of the tibia with
malalignment of the ununited butterfly fragments. Slight cra-
nial angulation of the distal fragment was noted. The stifle and
tibiotarsal joints appeared normal on examination.
Treatment/Management: The dog had a healing fracture
and had reached the stage where the deposition of a large ex-
tracortical fibrocartilaginous callus had made movement of the
fragments limited and nonpainful. The heavy callus seen at
presentation made fragment repositioning nearly impossible
were surgery to be attempted.
Radiographic examination of the limb at a later date showed
formation of a healing callus, but the fragments remained in an
overriding position and resulted in a permanent shortening of
the limb.
4

Case 4.117
Signalment/History: “Rascal” was a 3-year-old, male Shet-
land Sheepdog who had been struck by a car ten weeks earli-
er. A resulting right midshaft femoral fracture was treated with
an IM pin and multiple cerclage wires. The original repair had
failed and the same form of fracture treatment was repeated.
The second IM pin migrated and had been finally removed
several days previously by the owner.
Physical examination: Soft tissue atrophy was prominent in
the right pelvic limb. The non-union midshaft femoral frac-
ture was palpated. No draining tracts could be detected.
right femur with views of the normal left femur.
Radiographic diagnosis: A non-union midshaft femoral
fracture was seen with four cerclage wires at the fracture site.
The distal fragment was angled caudally on the lateral view,
and laterally on the VD view; however, the fragment seemed
free to shift in position. Only minimal early callus had formed
at the fracture site. The four cerclage wires had shifted toward
the fracture site. Small resorption sites on the periosteal surface
represented the original position of the cerclage wires before
their movement. Disuse osteoporosis was evident.
Differential diagnosis: Although the non-union status of
the fracture could be established, the question of the presence
of osteomyelitis was more difficult to determine. The absence
of a reactive periosteal response suggested that infection was
not present, but this was probably better determined clinical-
ly.
Treatment/Management: The fracture was plated. Radio-
graphs made five months later showed a satisfactory healing of
the femoral fracture.
4

Case 4.118
Signalment/History: “Bucky” was a 8-month-old, male
Poodle mixed breed with a history of injury to his left fore-
limb several months previously. The dog had not been pre-
sented for treatment at that time even though he was acutely
lame.
Physical examination: The affected limb appeared shorter
than the opposite limb. Despite not bearing full weight on the
limb, the dog actually showed only little pain on palpation.
The midshaft of the radius/ulna palpated thicker than expect-
ed, with a definite mass laterally and caudally. Flexion and ex-
tension were possible in both the elbow and antebrachiocarpal
joints.
Radiographic procedure: The forelimb was radiographed.
Radiographic diagnosis: A non-union fracture was noted
in the midshaft of the radius and ulna with overriding of
the fragments. The fragment ends showed both atrophic
and hypertrophic patterns typical of non-union fractures. A
pseudoarthrosis had developed between the proximal radial
and distal ulnar fragments. No signs of healing activity were
evident. The adjacent joints were within normal limits radio-
graphically. Note the degree of cortical thinning from disuse.
Treatment/Management: Because of the absence of pain
and “Bucky’s” ability to ambulate, the owners chose to not
consider treatment at this time.
Comments: If surgical treatment is to be undertaken, it is al-
ways helpful to have radiographs of the opposite limb to de-
termine the correction in the length of the bones that should
be attempted.
The differential diagnosis in this patient was not difficult, al-
though it must include an explanation for the shorter limb in
a young dog, the unusual findings on palpation, plus the his-
tory of trauma, as all of these suggest a problem associated with
fracture healing.
4

Signalment/History: “Jodi”, a 6-month-old, female Great
Pyrenees, was presented lame on the left pelvic limb. The
owner had just acquired the dog and knew no relevant clini-
cal history.
Physical examination: The stifle joint was painful on pal-
pation and muscle atrophy was prominent. Joint effusion
and/or a thickened joint capsule was palpated.
Radiographic procedure:Lateral studies of both stifle joints
were made because of the age of the dog.
Radiographic diagnosis (lateral views only): A chronic,
non-union avulsion fracture of the tibial crest on the left with
thickening of the patellar ligament (arrow). The stifle joint on
the right was normal.
Case 4.120
Comments: This injury was chronic as evidenced by the ab-
sence of any sharply defined bony fragments and by the pres-
ence of an early bridging callus. The patellar fat pad on the in-
jured limb could not be identified because of hemorrhage or
edema.
The location of the patella is almost normal when compared
with the opposite limb, as would be expected in a lesion in
which the tibial crest is displaced only a short distance.
4

4.2.2.6 Traumatic injuries to growing bones
Fractures seen in the skeletally immature bone that affect
growth areas are divided into those that are physeal and those
that are apophyseal. Of particular importance are the physeal
injuries, which ultimately affect the length and shape of the ra-
dius and ulna. In the pelvic limb, slippage of the capital epi-
physis often results in necrosis of the proximal epiphysis and
results in injury to the hip joint. Apophyseal injury to the tib-
ial crest has the possibility of causing chronic injury to the
femoropatellar articulation.
Physeal growth injuries
Physeal fractures affect those growth plates that provide the
length of the long bones. Physeal fractures have been conve-
niently divided into Salter Harris type I, in which the fracture
remains within the cartilaginous growth plate; type II in
which the fracture escapes from the cartilaginous growth plate
and enters the metaphysis; type III in which the fracture es-
capes from the cartilaginous growth plate and enters the epi-
physis; type IV in which the fracture is directed more longitu-
dinally with the fracture line passing through the epiphysis,
across the physis, and through the metaphysis; and type V in
which a crushing or sheering injury results in a bony bridging
of the growth plate. A type VI has also been described, in
which peripheral injury results in formation of a bony callus
that bridges the growth plate and prevents lengthening of the
bone. Of the physeal fractures, only Types III and IV enter the
joint space.
Injury to the physeal growth plates can result in growth dis-
turbance of several types. It can terminate growth across the
entire plate and result in what is frequently referred to as “pre-
mature closure” with cessation of bone growth. The injury
may also only center on a portion of the growth plate and re-
sult in an unequal injury, and subsequent unequal growth. If
the injury is less severe, the growth may only be delayed or
lessened and this pattern may be equal across the growth plate
or affect only a portion of the plate. Thus, it is possible to have
a range of results following injury. This range is also affected
by whether the long bone is solitary or paired. The radius and
ulna have the most commonly described growth problems. If
one bone has closure to growth, the continued growth of the
paired bone will result in marked bowing. It is also possible for
the adjacent joint to be destroyed as a result of the unequal
growth of paired bones. Thus, radiographic examination must
include both the elbow joint and the antebrachiocarpal joint in
such cases.
Injury to the growth plate of the proximal femur is intra-
articular and may result in destruction of the blood supply to
the capital epiphysis and subsequent avascular necrosis. This
type of injury is often seen in association with other pelvic in-
juries.
4

Case 4.120
Signalment/History: “Peete” was a 5-month-old, male
Dachshund with an abnormally shaped right pelvic limb. This
included a varus deformity centering on the distal tibia.
Physical examination: Palpation failed to identify any site
of pain or swelling. The varus deformity was easily seen and
the affected limb was slightly shorter. The pads on the foot had
worn unevenly.
Radiographic diagnosis: The abnormal growth of the dis-
tal tibia was characterized by cranial and medial angulation of
the distal portion causing a varus deformity. The shortening of
the affected bone was noted in addition to a marked angula-
tion of the tibiotarsal joint space. A malunion physeal fracture
was the most likely cause of the deformity.
Outcome: The owner did not want to pay for any reparative
surgery. “Peete” was discharged and not seen again.
Comments: Physeal injury often occurs in the forelimb.
However, this patient had an injury to the distal physeal plate
in the tibia that had resulted in uneven growth with delayed
growth medially. The injury must have been minimal because
of the absence of any clinical signs.
Traumatic injuries to growing bones 449
4

Signalment/History: “Rufus” was a 6-month-old, male
Labrador Retriever who had fallen down a flight of stairs 24
hours earlier and had become non-weight-bearing on the left
pelvic limb.
Physical examination: Palpation of the limb did not elicit
pain and no evidence of soft tissue swelling was noted.
Radiographic diagnosis: A Type 1 Salter-Harris fracture
was seen in the proximal tibia with only minimal displacement
of the fragments. The metaphysis was shifted slightly in a me-
dial direction (white arrow). An associated incomplete frac-
ture of the proximal fibula was detected (black arrow).
Comments: Generally, this type of physeal injury does not
affect bone growth if the fragments are maintained in a good
position during healing.
Case 4.121
4

Signalment/History: “Cindy” was a 4-month-old, female
Fox Terrier who had fallen and become lame on her left fore-
limb.
Physical examination: Crepitus was palpated in the left el-
bow joint.
of the elbow.
Radiographic diagnosis: An oblique Type IV Salter-Harris
fracture separated the lateral condyle with marked proximal
and lateral displacement.
Treatment/Management: A single bone screw and short
Steinman pin were used for reduction and stabilization.
A follow-up radiograph four months after the injury showed
healing of the humeral fracture.
Comments: A fracture of this type in smaller breeds dog is
often associated with the failure of complete closure of the
growth area between the two condyles. Therefore, the oppo-
site limb should be radiographed to ascertain whether or not
the persistence of the cartilage plate is bilateral, thereby form-
ing a zone of weakness in the opposite limb.
Case 4.122
4

Signalment/History: “Samantha” was a 6-month-old, fe-
male puppy who had become lame after “playing with the
children”.
Physical examination: She was non-weightbearing on the
right pelvic limb and the stifle region was swollen and painful.
Radiographic procedure: Both views were made of the
tibia including the stifle joint.
Radiographic diagnosis: A combination of injuries to the
growth plate of the tibial crest and the proximal tibial growth
plate was noted. The fracture line started from the physeal
plate and extended into the metaphysis making this a Salter-
Harris Type II injury. This combination of apophyseal and
physeal injury is not common. The fibula was fractured with-
out fragment displacement (arrows). Joint effusion, probably
hemorrhagic, was evident.
Treatment/Management: The tibial crest and proximal
epiphysis remained united and the entire fragment was re-
duced by the use of K wires.
Comments: Fractures of this type usually heal quickly in a
puppy and a possible delay in growth of the tibia would be
compensated for by a slight change in the angulation of the sti-
fle joint during walking.
Comparison views of the normal limb would have been help-
ful. Follow-up radiographs would have assisted in recognizing
any problem in bone growth.
Case 4.123
4

Case 4.124
Signalment/History: “Bear” was an 8-month-old, male
German Shepherd mix who had been limping on his right
forelimb for several months. The foot was in a valgus deform-
ity. He seemed to be without pain while walking.
Physical examination: Muscle atrophy was obvious
throughout the right forelimb. The valgus deformity was cen-
tered at the radiocarpal joint. Movement of the elbow joint
was without pain, but was not normal. Movement of the foot
showed the angulation of the paw. The nature of the injury
could not be determined during the physical examination.
The left limb appeared normal on examination.
Radiographic procedure: Two views of both forelimbs
were made.
Radiographic diagnosis:In the right forelimb, shortening of
the radius had lead to a luxation of the humeroradial joint, de-
struction of the trochlear notch, and luxation of the humero-
ulnar joint, which essentially destroyed the elbow joint. Un-
equal growth at the distal radial physeal plate had caused a
marked valgus deformity of the foot. The degree of injury to
the radiocarpal joint could not be clearly identified.
This deformity was secondary to closure of the proximal radi-
al physeal plate and unequal growth of the distal radial physeal
plate.
Note that the distal ulnar physeal plate on the affected limb re-
mained open. The affected radius was 2.7 cm shorter and the
affected ulna was 1 cm shorter than in the left forelimb. The
opposite limb was normal by comparison with all its growth
plates open.
Treatment/Management: Surgical osteotomy of the ulna
permitted a slight reduction in the degree of elbow joint lux-
ation. A radial osteotomy fixed with an IM pin partially cor-
rected the valgus deformity and lateral rotation of the foot.
Even with excellent reduction of the elbow joint luxation, the
articular surfaces could not be made normal and the persist-
ence of joint incongruity (arthrosis) continued to exist.
Comments: The etiology in lesions of this type usually re-
mains a question. It is assumed that a traumatic event influ-
enced the disruption of the blood supply to the growth areas;
however, evidence of the trauma is often not included in the
clinical history and is not seen on the radiographs.
4

4
Left Right

Case 4.125
Signalment/History: “Bruiser” was an 8-month-old, male
Saint Bernard with abnormal curvature of both fore limbs.
The owners had only recently acquired the dog and knew of
no history that might have been helpful.
Physical examination: The left limb had a valgus deformi-
ty centered at the carpus and the limb appeared shorter than
the right. Palpation of the elbow and carpal region on the af-
fected limb was abnormal, while palpation of the right limb
was thought to be normal. The foot on the right was exter-
nally rotated and the carpus dropped almost to the ground.
Differential diagnosis: Because of the age of the dog and the
breed, a growth abnormality was considered.
Radiographic procedure: Views of both forelimbs were
made.
Radiographic diagnosis: The radius was 4 cm shorter on
the more severely affected limb, and the ulna was 3.8 cm
shorter. Both the elbow and antebrachiocarpal joints were
severely damaged in this limb. The distal radius was angled
laterally and the distal one third of this bone was wider than
normal with uneven cortical thickness and strong “struts” ex-
tending between the cortices. The trochlear notch was mal-
formed and displaced proximally with increase in the width of
the humeroulnar joint space. The medial coronoid process was
badly damaged. The humeroradial joint space was widened.
The proximal radial growth plate remained partially open.
The radiocarpal joint surfaces were angled distomedial to
proximolateral resulting from the unequal growth of the adja-
cent growth plate. This caused the valgus deformity of the
foot. The distal radial and ulnar physeal plates were closed.
The distal ulna was displaced proximally and angled cranially.
A severe deforming arthrosis was present in the proximal and
distal joints.
The bones and joints of the right forelimb were within nor-
mal limits with the exception of a slight lateral angulation of
the foot.
The etiology of the growth deformity on the left was prema-
ture growth plate closure of unknown etiology.
Treatment/Management: The owner wanted to have cor-
rective surgery on the forelimb performed. Additional radio-
graphs showed the dog to also have severe arthrosis secondary
to hip dysplasia. and the dog was euthanized.
Comments: Skeletal growth abnormalities are much more
difficult to treat successfully in giant breeds and careful exam-
ination of the entire skeleton is suggested before treatment of
one region is considered.
4

Case 4.126
Signalment/History: “Sami” was a 5-month-old, male
Beagle, whose right forelimb had been stepped on when he
was six weeks of age. A progressive lameness had developed in
the right forelimb over the previous month.
Physical examination: Movement of the right elbow was
not normal and the right forelimb appeared slightly shorter
than the left. Lateral rotation of the foot was evident.
Radiographic procedure: Both forelimbs were radio-
graphed.
Radiographic diagnosis: A marked separation was noted
between the humeral condyle and the radial head in the right
forelimb. The trochlear notch was displaced proximally caus-
ing an increase in the width of the right humeroulnar joint
space. The proximal radial growth plate was partially closed.
Rotation of the distal radial epiphysis had injured the radio-
carpal joint. The distal radial growth plate was closed. The ra-
dius and ulna remained straight, but the foot was externally
rotated. The radius was 1 cm shorter than the radius on the
left. The diagnosis was delayed physeal growth in the right ra-
dius resulting in a destructive elbow luxation and external ro-
tation of the foot.
Treatment/Management: Midshaft ulnar ostectomy was
attempted. The dog’s clinical status improved greatly, but the
humeroulnar subluxation remained causing a continued lame-
ness.
Comments: Treatment must consider the status of the adja-
cent joints in addition to attempting to restore the length of
the bones.
4
Right Left

Case 4.127
Signalment/History: “Shemi” was a 2-month-old, female
Collie with a right forelimb that was not “straight”. The limb
had been normal at birth.
Physical examination: The right thoracic limb appeared
shorter than the opposite limb and the right foot was deviated
laterally. No pain was evident on palpation although the pup-
py was difficult to examine.
forelimb.
Radiographic diagnosis: Physeal injury to the distal radius
and ulna resulted in a marked valgus deformity of the foot (ar-
rows). The radius was 1 cm shorter, and the ulna 1.5 cm short-
er than the bones in the opposite limb. The modeling and
malalignment in the distal radial metaphysis suggested a possi-
ble Type 1 physeal slippage that had not been recognized. The
injury may have delayed radial growth; however, ulnar short-
ening had resulted in an apparent overgrowth of the radius
with the radial metaphysis displaced medially. This displace-
ment had protected the radiocarpal joint.
Note the increase in width of the ulnar physis suggesting a per-
sistent blood supply to the epiphysis that permitted continued
cartilage production. In comparison, there was obviously a
lack of blood supply to the metaphysis that delayed mineral-
ization of the cartilage and growth of the bone. The resulting
dissimilarity of growth of the two bones caused them to ap-
pear as an “X” when viewed on the craniocaudal view instead
of two parallel bones. The bones and joints in the left limb
were normal.
Treatment/Management: The puppy was treated with a
splint to correct the valgus deformity with the hope that the
remaining growth potential in the bones would result in some
correction of the deformity. The puppy was lost to follow-up.
4
Right Left

Case 4.128
Signalment/History: “D’Artagnan” was a 10-month-old,
male Irish Setter whose name had not protected him from
some type of trauma. The injury had occurred three months
previously and the owners had been waiting for him to “im-
prove” in the ensuing time. When this did not occur, they
brought him to the clinic for treatment.
Physical examination: The left pelvic limb was obviously
abnormal with severe soft tissue atrophy. Movement of the hip
joint was painful and limited.
Radiographic procedure: Only a VD view of the pelvis
was made.
Radiographic diagnosis: The misshapen left femoral head
and neck appeared to be subsequent to a chronic physeal
fracture. The malshapen left acetabulum was secondary to at-
tempted repair of the femoral physeal fracture. The muscle
atrophy in the left pelvic limb was extensive. Obliquity of the
pelvis made diagnosis difficult, but healing of a left sacroiliac
joint luxation, left pubic fracture, and left ischial fracture were
all suspected.
Note the wide white shadow cast by a skin fold extending
across the left hip joint
Comments: The injury was most probably a subcapital phy-
seal fracture plus fractures at three locations in the pelvis
which had occurred at the time of the trauma three months
earlier. A portion of the avascular capital epiphysis remained
yet to be resorbed. The femoral neck had undergone osteo-
clastic modeling because of disuse. The acetabulum may have
been fractured, but that would be uncommon with a physeal
fracture. More likely, the acetabulum had simply remodeled
and become flattened because of disuse.
4

Case 4.129
Signalment/History: “Angelo”, a 7-month-old, male Irish
Setter, had had a suspected trauma two months previously. A
coxofemoral luxation was diagnosed on physical examination.
Physical examination: Generalized soft tissue atrophy was
noted in the pelvic region. Palpation of the right hip joint was
abnormal and either a fracture or luxation was suspected.
Radiographic diagnosis: A chronic physeal fracture of the
right femoral neck had resulted in avascular necrosis of the
right femoral head with marked resorption of the right femoral
neck, and prominent remodeling of the right acetabulum. The
femoral head remained essentially unchanged. The fracture
probably had remained a non-union, although this was diffi-
cult to ascertain on this single view. The soft tissue atrophy
suggested that the dog had not used the limb since the time of
injury.
Comments: The radiographic findings were typical of those
following a subcapital physeal fracture of the femoral head in a
skeletally immature dog. The femoral neck quickly resorbed
due to disuse and because it retained its blood supply. The cap-
ital epiphysis contained its original bone content because the
destruction of its blood supply had prevented a rapid de-
mineralization. The acetabulum had flattened because of
disuse. The sclerosis in the subtrochanteric region of the femur
reflected the increased stress through that part of the bone.
4

Case 4.130
Signalment/History: “Schwartz” was a 9-month-old, fe-
male Labrador Retriever who had been struck by a car two
weeks earlier. A luxated hip had been reduced twice without
any success.
Physical examination: A painful right hip joint with abnor-
mal motion was noted with a suspected luxated femur.
Radiographic procedure: Multiple views of the pelvis were
made for the right hip.
Radiographic diagnosis: The luxated right hip had a sub-
capital physeal fracture and an avulsion of the lesser trochanter
(black arrows). The minimal soft tissue mineralization was
probably early callus formation as would be expected around
an unstable fracture in a skeletally immature patient two weeks
post-trauma. The soft tissue atrophy was commensurate with
the clinical history of two weeks duration.
Note the small ossification center at the caudal aspect of the
symphysis pubis.
4

Signalment/History: “Sidney” was a 9- or 10-month-old,
male cat who had been found lame by his owner.
Physical examination: The right pelvic limb was swollen
and crepitus could be palpated.
pelvic limb.
Radiographic diagnosis: A Salter-Harris Type I distal
femoral physeal fracture was noted with typical caudal and
proximal displacement of the epiphysis. There was no evi-
dence of an intracondylar fracture.
Treatment/Management: The thorax was radiographed
because of the presumed traumatic etiology and was within
normal limits.
Two Kirschner wires were placed in a crossing fashion and the
reduction was satisfactory.
Comments: Typically, physeal fractures at this location have
a small triangular fragment of caudally located metaphyseal
bone still attached to the epiphysis resulting in a classification
of Salter-Harris Type II. This does not seem to have been
present in this patient.
Case 4.131
4

Case 4.132
Signalment/History: “Goldie” was a 6-month-old, female
Retriever cross breed who had been hit by a car two days ear-
lier. The dog had been treated in an emergency clinic, where
a splint had been placed on the fractured left tibia. She was
then referred.
Physical examination: The fracture in the midshaft of the
left tibia could be palpated and was studied on the referral ra-
diographs. In addition, crepitus was noted in the right hip and
movement of the right pelvic limb was painful.
pelvis.
Radiographic diagnosis (at presentation): The slipped
right capital epiphysis remained within the shallow acetabu-
lum and had lost subchondral density. Minimal soft tissue cal-
cification (early callus) was noted within the soft tissues sur-
rounding the femoral neck. These features suggested an injury
of more than two days duration.
In addition, an undisplaced fracture in the right ischium (black
arrows) was present and the ischiatic tuberosity was avulsed
(white arrows), indicating torn attachments of the biceps
femoris or semitendinosus muscles.
4
At presentation

The opposite femoral head was positioned loosely within the
acetabulum, but the hip joint was felt to be otherwise normal.
Treatment/Management: An attempt was made to surgi-
cally stabilize the capital epiphysis through placement of four
small Kirschner wires. The limb was placed in an Ehmer sling
after surgery. The tibial fracture was incomplete and the fibu-
la was unaffected, so this region of the limb was only splinted.
Additional radiographs were made two months later.
Radiographic diagnosis (month 2): Resorption of the
femoral neck had occurred with beginning resorption of the
femoral head. The head had slipped along the pins and had im-
pacted on the neck, where it could be seen to be healing. The
change in the contour and shape of the femoral head, the ace-
tabular modeling as to accept the reshaped femoral head, and
the marked sclerosis of the subchondral bone suggested devel-
opment of a post-traumatic arthrosis that will be of clinical im-
portance in a dog of this size.
Comments: Owners often do not admit that they have de-
layed treatment of trauma patients.
4
Month 2

Case 4.133
4

Signalment/History: “Heidi” was a 7-month-old, female
German Shepherd who was brought to the clinic because of
not walking “quite right”. The only history that the owners
could offer was that she was “run over by a truck” when she
was eight weeks old. She had received no treatment at that
time.
Physical examination: Both hip joints palpated in an ab-
normal manner with limited motion. Soft tissue atrophy was
evident bilaterally, more prominent on the left.
pelvis.
Radiographic diagnosis: Chronic bilateral hip joint injury
had resulted in a partial resorption of both femoral necks and
remodeling of the acetabulae leading to a marked flattening.
The subchondral sclerosis was more severe on the right. Both
capital epiphyses had lost bone density, were partially re-
sorbed, and were not reunited with the femoral necks. The
femoral cortices were thin suggesting either a generalized dis-
use or perhaps nutritional disease.
Malunion fractures of the pubis and ischium plus fusion of the
right sacroiliac joint had resulted in a marked cranial displace-
ment of the right hemipelvis.
The most likely diagnosis was capital physeal fractures in a
puppy with marked post-traumatic resorption and non-union
of the femoral heads, and severe secondary arthrosis.
Treatment/Management: Bilateral femoral head ostectomy
was performed. “Heidi” had delayed recovery during the post-
operative period, probably because of the ineffective use of
physiotherapy and never regained a good use of her pelvic
limbs.
Comments: A major problem in this patient was that the in-
jury had occurred prior to the formation of the hip joints. As
a consequence, the severe injury to the joints was only par-
tially due to the trauma. It was really largely due to the fact that
the hip joints were only partially developed at the time of the
trauma.
4

Apophyseal fractures
Skeletally immature bone may suffer apophyseal fractures that
are of an avulsion nature, with separation of the apophyseal
growth center. These have a characteristic appearance with a
“pulling away” of the growth center from the parent bone and
can obviously occur only in specific anatomic locations. The
sites most commonly affected are the supraglenoid tuberosity,
the greater trochanter of the femur, the tibial crest or tuberos-
ity, the calcaneal tuber, and the ossification center for the ole-
cranon process. Additional sites include the tubercles of the
proximal humerus, the crest of the ilium, the ischiatic tuberos-
ity, the lesser trochanter of the femur, and the tip of the ac-
cessory carpal bone.
In fractures of this type, the bony fragment usually separates
from the parent bone with the fracture line located within the
cartilaginous growth plate. Because the apophyseal growth re-
gions do not contribute prominently to the length of the bone,
the secondary affects of the injury are not as severe as in phy-
seal fractures. Perfect repositioning of the avulsed fragment
that insures renewed physeal growth is not required. Separa-
tion of the tibial crest is somewhat unique since avulsion alters
the attachment of the patellar ligament and, in that way, the fit
of the patella in the femoral trochlea may be altered resulting
in a secondary arthrosis.
Another group of avulsion fractures in the developing skeleton
occur at sites that actually do not have a separate apophyseal
growth center, but are only sites for the attachment of muscle
tendons, such as the medial or flexor epicondyle of the distal
humerus. Because this type of injury occurs in the developing
bone, they have clinical and radiographic features in common
with the apophyseal fractures.
4

Case 4.134
Signalment/History: “Rusty”
was a 7-month-old, male Brittany
who had fallen from the seat of a car
onto the ground. He was immedi-
ately lame on the left pelvic limb.
The limb was then placed in a cast
for two weeks. On removal of the
cast, he continued to show lameness
and was brought to the clinic for
evaluation.
Radiographic procedure: Studies
were made of the stifle joint in both
limbs.
Radiographic diagnosis (day
66): A chronic avulsion fracture had
separated the tibial crest ossification
center on the left and could now be
seen with a partial bony union of the
tibial crest to the parent bone. The
patella was more proximally posi-
tioned than seen on the normal
limb. The “skyline” views showed
the patella resting in the trochlear
groove in a near-normal manner.
The right limb was normal in com-
parison.
Comments: A number of etiologies
could have been involved in this
case. Is it a case of delayed bony
healing over a two-month period
because the limb had not been stabi-
lized well, so that the continued mo-
tion of the fragment delayed the
healing process? Or, was the frag-
ment stabilized by the formation of a
fibrocartilaginous callus and that
explains the lucency between the
fragment and parent bone? Or, was
“Rusty” only showing a mechanical
lameness, the result of the limb be-
ing immobilized for two months and
the fracture was actually well stabi-
lized?
4
Left Right

Case 4.135
4
Left Right

Signalment/History: “Brandy” was a 4-month-old, female
German Shepherd who had fallen a distance of 1.5 meters the
previous evening and had been lame since.
Physical examination: Pain and swelling were obvious
around the left stifle joint.
stifles.
Radiographic diagnosis: An acute avulsion of the tibial
crest on the left was noted with the right normal in compari-
son. Evaluation of the acute nature of the injury was support-
ed by the clinical history and a failure to note any bridging cal-
lus. The tibial crest was seen displaced proximally on the cau-
docranial view (arrows).
Treatment/Management: The tibial crest was repositioned
using two K wires. Radiographs made postoperatively showed
more clearly the small avulsion from the distal aspect of the
patella indicating a tendenous tearing at that location.
Radiographs of the injury three weeks later showed the frac-
ture to have healed with the formation of a bridging bony cal-
lus.
Comments: It may be difficult to determine the healing of
an apophyseal fracture since the separation created by the avul-
sion is filled with cartilaginous tissue and presumably will re-
main cartilage until growth ceases. The filling of this space
with a bony callus suggests that the healing has hastened the
closure of the cartilage growth plate. An early closure should
not result in skeletal anomaly of clinical importance.
The comparison radiographs made the changes in the injured
limb easier to understand and are a “must” in the examination
of skeletal pain or lameness in the skeletally immature patient.
4

4.2.2.7 Radiographic changes of osteomyelitis
The radiographic changes associated with bone infection are
varied (Table 4.15). Traumatically induced bone infection can
be secondary to a bite wound that has resulted in a soft tissue
infection, which ultimately spreads to the bone causing an os-
teomyelitis. In this situation, the infected bone often does not
cause clinical signs nor is it evident on the radiograph until
days or weeks after the trauma. Consequently, the soft tissue
wound will have healed and been long forgotten by the time
the patient presents with pain or lameness.
Another way in which osteomyelitis can occur, is in conjunc-
tion with an open fracture in which the contaminated wound
results in bone infection. This direct implantation of the in-
fectious organism can also be the result of a puncture wound,
e.g. a bite wound. A third form of osteomyelitis occurs fol-
lowing the open reduction of a fracture with resulting
hematogenous infection at the site of the traumatized soft tis-
sue.
The pattern of radiographic change associated with a soft tis-
sue infection extending into bone is characterized early by pe-
riosteal new bone formation. Later destructive changes can be
identified within the bone. Radiographically, the pattern of
bone infection following a deep bite wound is relatively easy
to recognize especially if it is near the midshaft of the bone.
The features of periosteal new bone, involucrum formation,
and sequestration are all possible. If the infection is associated
with a fracture, detection of the osteomyelitis is difficult be-
cause the features of the infection are superimposed over the
callus formation and bone modeling associated with fracture
healing. Radiographic patterns can extend from one of a re-
sulting non-union without any signs of reactive bone to one
in which a fracture fragment assumes the role of a sequestrum,
and bony callus forms and bridges the site of osteomyelitis. If
fixation devices have been positioned to aid in fragment stabi-
lization, the osteomyelitis may center around the metallic
plates or screws. Often bone lysis occurs with loosening of
these devices. That lysis may be the only indication of the un-
derlying osteomyelitis evident on the radiographs.
For these reasons, the diagnosis of osteomyelitis in association
with a fracture and subsequent healing is best made on the ba-
sis of the clinical signs of a non-union or delayed union frac-
ture with heat, swelling, and the presence of a draining tract.
The wide variety of radiographic patterns present in associa-
tion with bone infection secondary to trauma means that iden-
tification of a sequestrum with concurrent involucrum forma-
tion is rather infrequent.
Table 4.15: Radiographic features of osteomyelitis
1. Extensive soft tissue infection
a. soft tissue edema and swelling
b. minimal periosteal new bone formation
2. Deep bite wound
a. periosteal new bone formation
b. soft tissue edema and swelling
c. region of bone lysis
d. uncommon for a visible sequestrum to develop
3. Associated with an open fracture
a. soft tissue signs may persist from the original injury
I. subcutaneous emphysema
II. edema and swelling
b. failure of callus formation as expected
c. periosteal new bone may be present
I. has no pattern of formation as normal callus would
II. pattern is indistinct
III. pattern may be away from the fracture site
IV. eventually could form an involucrum
d. bone lysis
I. difficult to separate from resorption at a fracture site
II. eventually could form a resorption cavity
e. sequestrum
I. can form eventually
4. Associated with a surgically reduced fracture
a. soft tissue swelling is confused with post-surgical swelling
b. early periosteal new bone is confused with early callus
I. formation away from fracture site may be suggestive of infection
c. failure of callus formation is confused with delayed healing
d. avascular fragment
I. suggested by persistence of sharp margination
II. suggested by persistence of original bone density
e. sequestrum
I. can form eventually
4

Case 4.136
Signalment/History: “Molly” was an 18-month-old, fe-
male mixed-breed dog with a history of generalized disease
characterized by a disseminated pneumonia complicated by
the development of a pneumothorax. During treatment of this
condition, she was noticed to be lame on the right pelvic limb.
Physical examination: The stifle joint was swollen.
Radiographic procedure: Studies were made of both stifle
joints.
Radiographic diagnosis: A chronic avulsion fracture of the
tibial crest was noted with a destructive pattern within the
avulsed fragment and the adjacent tibia. Soft tissue swelling
was noted plus effusion within the stifle joint.
Treatment/Management: The history made us suspicious
that this was not just a traumatic avulsion fracture in a healthy
bone. Both the avulsed fragment and the parent bone con-
tained a destructive pattern and bridging callus could not be
identified. Further examination of “Molly” indicated ulcera-
tive skin lesions, eye lesions, and the previously diagnosed per-
sistent pneumonia. A biopsy of bone tissue taken from the
proximal tibial metaphysis was evaluated as inflammatory and
distinctive organisms with unstained and double-contoured
walls were diagnosed as Blastomyces dermatitidis.
Radiographic changes of osteomyelitis 471
4

Case 4.137
Signalment/History: “Morgan” was a 1-year-old, male
Newfoundland with a history of trauma to a pelvic limb.
Physical examination: The limb was severely swollen and
the examination was limited.
Radiographic diagnosis (at presentation): A spiral frac-
ture of the tibia with marked overriding of the fragments re-
sulted in protrusion of the distal tip of the proximal fragment
into the soft tissues adjacent to the medial malleolus. The tar-
sus appeared not be affected by the trauma.
Treatment/Management: The fractured tibia was reduced
by the placement of interfragmentary screws and a single
metallic pin placed within the medullary cavity of the tibia.
Radiographic diagnosis (week 2): The first postoperative
radiographic study was made two weeks after surgery and
showed early callus formation in several locations along the
distal tibial shaft. The borders of the fracture fragments had be-
come difficult to identify suggesting a healing process. Good
apposition and alignment of the fragments remained as at the
time of surgery.
4 At presentation
Week 2

Radiographic diagnosis (month 2): The second postoper-
ative study made 8 weeks after surgery showed lucent cavities
around the screws with a long lucent cavity at the site of the
fracture line. Lucency was seen around the distal portion of the
intramedullary pin. Apposition and alignment of the fragments
remained as before.
Outcome: The form of fixation used was not sufficient to
stabilize the fragments in the face of the bone infection. The
owner refused further treatment in spite of being advised that
the fixation would weaken, probably collapse, and the fracture
end as a malunion at the best.
Comments: The presence of reactive periosteal new bone on
the first postoperative study at a distance from the major frac-
ture site suggests that it is secondary to infection and not a pat-
tern expected with callus formation. The second postoperative
study clearly shows the destructive pattern of bone infection
with the osteomyelitis causing weakness of the metallic im-
plants at the site of fracture healing.
4
Month 2

Case 4.138
Signalment/History: “Riley” was a 7-year-old, male Irish
Setter with a history of having been in a dogfight two months
previously. The left forelimb became swollen four weeks after
the trauma and the dog was treated with antibiotics without
improvement. The earlier radiographs were not available for
examination, but osteomyelitis had been diagnosed on the
study.
Physical examination: The left forelimb was swollen and
painful to palpation. The adjacent joints palpated normally.
Radiographic procedure: Two views of the left antebrachi-
um were made.
Radiographic diagnosis: Periosteal new bone affected both
the left radius and ulna and assumed two patterns: the first pat-
tern was that of an intact smooth elevation, while the second
pattern was that of roughened spicules directed laterally and
caudally (white arrows). The sclerotic pattern noted within
the medullary cavities was probably summation due to the ex-
ternal cuff of new bone. The zone of transition was rather
short. No evidence of cortical destruction was noted.
The radiographic signs were compatible with the tentative di-
agnosis of osteomyelitis following a bite wound. The level of
activity of the bony changes was difficult to ascertain, but the
pattern of new bone forming spicules suggested the lesion was
active.
Differential diagnosis: The diagnosis of osteomyelitis re-
mained high on the list because of: (1) the clinical history, (2)
the interpretation made from the first radiographic study, and
(3) the features on the radiographs made two months after the
injury. The bony changes were progressive but remained be-
nign in nature.
4
At presentation

Treatment/Management: The patient was treated with an-
tibiotics and showed some improvement. Two weeks later, the
radiographic appearance of the lesion remained the same. Af-
ter a further two weeks, the lesion was curetted in an effort to
hasten healing of the suspected bone infection. The surgical
biopsy obtained at that time was that of a “fibrosing periosti-
tis” with the tissues suggestive of an old inflammatory lesion
in a stage of resolution with a low-grade smoldering inflam-
matory component. The patient showed periodic lameness
during the subsequent healing of the lesion.
Outcome: Radiographs were made eleven months later be-
cause of the dog’s continued failure to use the limb normally
and showed persistent non-active smooth periosteal new bone
secondary to the chronic osteomyelitis and surgical curettage.
Note the new bone forming in the interosseous ligament
(black arrow). The lesion was thought to be in a healing phase
at this time.
Comments:The diagnosis in this case was rather easy because
of the clinical history of a bite wound and the interpretation of
the earlier radiographs. The differential diagnoses for a bony
lesion of this radiographic appearance lying adjacent to the nu-
trient foramina should include: hematogenous osteomyelitis,
hematogenous fungal bone infection, metastatic spread of ma-
lignant tumor, bony callus around an incomplete radial and ul-
nar fracture, and even a bizarre form of panosteitis. Diagnosis
is made easier by the use of radiographs of the opposite limb
as well as follow-up radiographic studies of the injured limb.
4
11 months later

Case 4.139
Signalment/History: “Rusty” was a 2-year-old, male Visz-
la with a history of acute lameness of the right thoracic limb.
He had a history of fighting with other dogs.
Physical examination: Pain was elicited upon deep palpa-
tion of the antebrachium. No other signs of abnormality were
noted.
Radiographic procedure: Studies were made of the right
forelimb.
Radiographic diagnosis: Radiolucent cavities with sharp
margins were present in the right radius and ulna surrounding
the nutrient foramina (arrows). Features of secondary reactive
bone were not present.
Differential diagnosis: Lameness in a 2-year-old dog could
be due to a variety of etiologies including inflammation, neo-
plasm, or even a developmental lesion such as a bone cyst with
a pathologic fracture. If the lesion was inflammatory, it could
have been either the result of a puncture wound, been
hematogenous, or have been spread to the bone from the ad-
jacent soft tissue.
Treatment/Management: The lesions were curetted in an
effort to determine the etiology as well as to be possibly cura-
tive. A cancellous bone graft was implanted in the region. The
surgical biopsy was evaluated as “containing necrotic bone
with no evidence of active inflammation” and the lesion was
treated as a sterile abscess.
The use of the cancellous bone graft plus rather deep curettage
created a radiographic pattern that was somewhat confusing.
Two months later the dog could bear weight on the limb. The
slow clinical improvement suggested the presence of an active
bone infection; however, no draining tract was present. Three
months following surgery, the dog remained slightly lame on
the limb, but with no soft tissue swelling or heat, and no drain-
ing tract. Recovery after that time was progressive and un-
eventful.
Comments: The lesions were thought to be hematogenous
not only because of the absence of any positive history of bite
wound or other injury, but also because of its location at the
entrance of the nutrient vessels to the bone. This etiology was
also supported by the absence of any periosteal new bone that
would have characterized spread of an infectious lesion from
the surrounding soft tissues. Lesions characterized by bone de-
struction at the site of the nutrient foramina need to be thor-
oughly evaluated for both inflammatory and neoplastic lesions.
4

Case 4.140
Signalment/History: A 1-year-old, male kitten was pre-
sented following a catfight, where he had sustained bite
wounds in the distal left pelvic limb. The owners said that he
had been non-weightbearing over the whole week since the
injury.
Physical examination: The left hindlimb was swollen,
warm, and painful to palpation. Draining tracts were present
in the tibial region.
left pelvic limb.
Radiographic diagnosis: A destructive pattern was cen-
tered on the distal tibial physeal growth plate with the sugges-
tion of collapse around the growth plate (left, arrows). A com-
bination of periosteal new bone and some medullary new
bone surrounded the destructive portion. The tibiotarsal joint
appeared swollen; probably due to a joint effusion. Injury to
the subchondral bone was difficult to evaluate.
In addition, a primarily destructive lesion was present in the
proximal tibial metaphysis that extended into the subchondral
bone. A similar lesion was also present in the lateral condyle of
the femur (right, white arrows). Stifle joint effusion was not-
ed. Soft tissue swelling was evident throughout the limb.
Differential diagnosis: The destructive patterns in the tibia
and femur suggested multicentric osteomyelitis: (1) secondary
to direct implantation into the bone from two separate bite
wounds, (2) secondary to one bite wound with the second le-
sion occurring after spread into the medullary cavity, (3) sec-
ondary to soft tissue infection with direct extension into the
bone, or (4) secondary to soft tissue infection with hematoge-
nous spread to the bone. The joint effusion suggested an in-
fectious arthritis in both the stifle and tibiotarsal joints.
Two destructive lesions in one bone in a one-year-old cat with
a history of fighting rules out most other diagnoses other than
osteomyelitis.
Treatment/Management: Radiographs made six weeks lat-
er, after treatment with antibiotics, showed healing of the
bone lesions. The cat was gaining weight and using the limb
near-normally. All the soft tissue tracts had healed at that time
with one exception.
Comments: The “cord-like” dense lesions in the proximal
tibia (black arrows) suggested bone infarcts providing support
for the idea that the lesions were at least partially due to
hematogenous spread.
4

Signalment/History: “Red” was a 3-year-old, male Ger-
man Shepherd mixed breed with a history of a surgically treat-
ed femoral fracture some months earlier. He was presented at
this time because of a draining tract near the stifle joint. Ac-
cording to the owner, he had not used the limb normally since
the fracture.
Physical examination: Muscle atrophy of the right pelvic
limb was prominent. Palpation of the thigh indicated a hard
mid-shaft mass. Movement of both hip joints was abnormal
with a feeling of joint laxity. The opening of the draining tract
was medial to the stifle joint.
Radiographic procedure: Two views of the pelvis and fe-
murs were made.
Radiographic diagnosis:A Jonas splint had been used to re-
duce the midshaft femoral fracture. The sleeve, spring, and pin
could be identified. The spring had escaped the sleeve proxi-
mally instead of driving the pin distally from the sleeve. Ap-
parently some stability had been achieved by this device, since
the fracture had healed; however, the cavity at the fracture site
and the persistent cortical shadows outlining the partially re-
sorbed sequestrum were indicative of a chronic osteomyelitis.
Case 4.141
The laxity in the right hip joint was most likely secondary to
hip dysplasia, disuse of the limb, and anteversion secondary to
the femoral fracture. The malunion fracture resulted in a val-
gus deformity of the proximal femur that negatively influ-
enced the development of the hip joint. The dog carried the
limb abducted forcing the femoral head into the acetabulum
despite the valgus deformity.
The subluxation of the left femoral head plus the remodeling
of the femoral head and neck are features of joint disease sec-
ondary to chronic hip dysplasia.
Treatment/Management: The fracture site was explored
surgically and the intramedullary device and the sequestrum
were removed. The wall of the involucrum was curetted. The
lesion healed satisfactorily although a mechanical lameness
persisted because of the bilateral joint disease influenced by the
trauma and the hip dysplasia.
Comments: The use of the Jonas splint was included in the
text only as a historical feature. A stabilization of this type
would not be used today. However, the consequences of a
combination of different metal types in orthopedic devices
were not recognized in the early 1960’s.
4

Case 4.42
Signalment/History: “Max”, a 3-year-old, male Cocker
Spaniel, was presented with a history of being bitten in the
shoulder five months previously. The lameness resolved, only
to recur two months after the injury. The soft tissue lesion ini-
tially healed and then a drainage track developed one month
prior to presentation (four months post trauma).
Physical examination: “Max” showed no signs of pain or
lameness during examination at the clinic. The drainage tract
was present medial to the left shoulder.
left shoulder.
Radiographic diagnosis: The 1-cm-in-diameter, radiolu-
cent lesion in the proximal metaphysis was characterized by
dense surrounding reactive bone, which had a sharp, intact
border. The lucent center of the lesion had probably contained
a sequestrum at one time. The reactive periosteal new bone
showed little sign of activity and suggested chronicity. The in-
volucrum showed a defect medially without sclerotic bone
that was a part of the cloaca (white arrow). The diagnosis was
a chronic osteomyelitis with a resorbed sequestrum.
Differential diagnosis: In a 3-year-old dog, a primary bone
tumor, a metastatic malignant tumor to bone, a hematogenous
osteomyelitis, or a fungal bone infection needed also to be
considered.
Treatment/Management: Because of the absence of clini-
cal signs, surgery was delayed until the soft tissue lesion had
healed. Even though the sequestrum could not be identified
on the radiographs, curettage to remove the lining of the in-
volucrum enabled the lesion to heal more quickly. Subsequent
radiographs made three weeks later showed the bony lesion
beginning to heal.
Comments: A chronic osteomyelitis in this location has fea-
tures that strongly suggest a malignant lesion.
4

Signalment/History: A 1-year-old, male Great Dane had a
draining tract on its left antebrachial region following a dog-
fight two months previously.
Physical examination: The draining tract was evident in the
distal portion of the left antebrachium. Soft tissue swelling was
prominent with heat and pain on palpation. Motion of the an-
tebrachiocarpal joint was slightly painful, but full motion was
possible.
Radiographic procedure: Studies were made of the left
forelimb.
Radiographic diagnosis (at presentation): The lytic zone
was centered on the lateral cortex and was surrounded by a
sclerotic bony mass that included intramedullary new bone
plus periosteal new bone. The bony response around the lu-
cent site was mature and nonreactive at that time. The zone of
transition was considered short. A radiographic pattern of this
nature was thought to be diagnostic of an osteomyelitis with
an involucrum and cloaca (white arrows). The sequestrum
could not be identified. The inflammatory lesion had not
spread to the adjacent radius.
Treatment/Management: The lesion was curetted, result-
ing in the removal of the involucrum and a sequestrum. Ra-
diographs were made eight days later.
Radiographic diagnosis (day 8 after presentation):These
showed a large saucer-shaped defect in the cortical bone.
Case 4.143
4

Signalment/History: “Chico” was a 10-month-old, female
Labrador Retriever mixed breed with a history of being in a
dogfight two weeks previously.
Physical examination: A large warm swelling was present
over the proximal antebrachial region. Two draining tracts on
the medial aspect of the limb exuded a hemorrhagic discharge.
The patient could bear weight on the limb, but was definite-
ly lame.
Radiographic procedure: Studies were made of the affect-
ed forelimb.
Radiographic diagnosis: The three radiographic views
were all made at the time of admission and clearly showed a
sequestrum within the involucrum (black arrows). Develop-
ment of a cloaca was prominent. Soft tissue inflammation had
lead to the development of reactive periosteal new bone on
the adjacent ulna. The radiographic pattern was typical of that
seen with a chronic osteomyelitis and sequestration following
a bite wound.
Treatment/Management: The lesion was curetted with re-
moval of the sequestrum. “Chico” was discharged much im-
proved and able to walk more comfortably on the limb.
Case 4.144
4

Case 4.145
Signalment/History: “Whompon”, a 5-year-old, female
Great Dane, was presented with a mass on her left forefoot.
The foot had been swollen for three weeks, but she had been
limping on this limb for a longer period. The dog had been
treated briefly with antibiotics with a resulting decrease in the
swelling; however, upon withdrawal of the medication, the
swelling recurred and drainage was noted.
Physical examination: Swelling was limited to the terminal
phalanges of the 3rd
digit on the left forefoot. The draining
tracts were also located on that digit.
Radiographic procedure: Multiple views of the left fore-
foot were made with an attempt to separate the swollen por-
tion of the 3rd
digit from the more normal digits.
Radiographic diagnosis: Subluxation of the distal inter-
phalangeal joint of the 3rd digit was noted along with marked
destruction of the subchondral bone of the 2nd phalanx. The
destructive lesion extended into the 2nd
phalanx with a dense
involucrum forming around the lytic area. Periosteal new
bone was minimal; however, a pattern of mineralization with-
in the soft tissues was noted. The 3rd phalanx did not appear to
be involved in this process. The soft tissue swelling extended
to involve most of the 2nd
digit.
Differential diagnosis: This destructive lesion that extend-
ed to the subchondral bone, but did not cross the joint space
was considered to be malignant. The fragmentation of the
subchondral bone and the amorphous appearance of the new
bone in the soft tissues were also strongly suggestive of malig-
nancy. In comparison, the formation of a distinct involucrum
suggested a more slowly expanding lesion and one that was be-
nign, possibly inflammatory. The limitation of the lesion to
one bone is more suggestive of malignancy than an inflamma-
tory lesion. The identification of even one malignant feature
in a radiographic pattern should make you strongly consider
malignancy for a diagnosis.
Treatment/Management: The entire digit was removed
surgically. The surgical biopsy revealed “an intense inflamma-
tory reaction throughout much of the tissue with neutrophilic
exudation and tissue necrosis”. Dissecting tracts were noted
grossly suggesting suppuration. The lesion appeared to be an
acute suppurative inflammation that had resulted in an osteo-
myelitis and inflammatory arthritis. No evidence of neoplasia
was present.
Comments: Treatment of a lesion in the 3rd
phalanx often re-
sults in surgical removal. Therefore, it was thought to be ap-
propriate to make the radiographic diagnosis of malignancy if
there was any suggestion of an aggressive lesion. The failure of
the inflammatory lesion to cross over to the third phalanx sim-
ply showed that not all lesions have “read the textbook” and
follow instructions on how they should typically behave.
4

Case 4.146
Signalment/History: “Duke” was an 11-year-old, male
Brittany that was presented with a chronic draining tract ven-
tral to the mandibular incisor region. This tract may have been
present for over a year.
Physical examination: The mandibular region was swollen
and the lower canine tooth on the right appeared loose.
Radiographic procedure: Studies were centered on the
lower incisor region.
Radiographic diagnosis:The area of soft tissue swelling was
noted with the canine tooth “floating” so that it was mis-
placed laterally and was without any apparent bony attach-
ment. A catheter (black arrow) was placed into a tract and ad-
vanced until the tip was located just medial to the canine
tooth. Alveolar bone was missing. No reactive new bone was
present, This pattern suggested a diagnosis of periapical osteo-
myelitis.
Treatment/Management: Surgical exploration produced a
grass awn (foxtail) as the etiology of the chronic infectious le-
sion.
Comments: A destructive lesion should always be considered
as possibly the result of a malignant process. In this patient, on
the other hand, the chronic drainage strongly suggested a di-
agnosis of osteomyelitis.
4

Signalment/History: “Damon” was an 11-year-old, male
Doberman Pinscher who had run off 12 days previously.
When the owner retrieved him from the authorities, he was
noted to be lame in both pelvic limbs. Trauma was the sus-
pected cause of the lameness.
Physical examination: Muscle wasting was evident in the
pelvic region and the hip joints were painful on palpation and
the extent of motion was limited. These findings suggested a
more chronic lesion.
and hip joints.
Radiographic diagnosis: A destructive pattern was noted
bilaterally in the femoral heads and necks, as well as within the
flattened acetabulae. Collapse of the joint space was noted
with marked destruction of the subchondral bone. Rather in-
distinct, generalized, reactive new bone surrounded the hip
joints. These features were supportive of a diagnosis of os-
teomyelitis and infectious arthritis. Generalized muscle wast-
ing indicated the chronic nature of the disease.
A transitional sacrococcygeal vertebral segment was present.
Treatment/Management: A joint tap was unsuccessful. A
biopsy of one femoral neck produced tissue with many neu-
trophils suggestive of a suppurative osteomyelitis.
Case 4.147
The dog was euthanized. At necropsy, both coxofemoral
joints contained turbid sanguineous fluid with yellow floc-
cules. Extensive loss of articular cartilage was characterized by
adjacent cavitary lesions. The inflammatory pattern extended
into the muscles surrounding the joint. No bacterial growth
was obtained from samples taken from the hip joints; howev-
er, Staphylococcus aureus was grown from blood cultures. The
diagnosis was a chronic suppurative arthritis.
Comments: “Damon” was typical of many patients in whom
trauma was suspected as the cause of lameness. Pets are often
“carefully” examined following an absence from their home
and the pelvic limb lameness was first noted following the re-
turn from being incarcerated. The owners thought the lame-
ness was associated with the recent events. The radiographic
changes indicated that the inflammatory process was chronic
with severe destruction of both hip joints. Hematogenous
seeding was thought to be possible because of the diseased
syovium secondary to chronic arthrosis from hip dysplasia.
4

4

Signalment/History: A 4-year-old, male Retriever had
been struck by a car and was immediately brought to the clin-
ic.
Physical examination: The dog could not walk. He was in
great pain and would not permit a thorough examination. Pain
was palpated in the midlumbar region.
Radiographic procedure: Lateral views of the thoracolum-
bar spine were made.
Radiographic diagnosis (day 1): Collapse of the disc space
at L3–4 was prominent.
Differential diagnosis: Without any of the radiographic fea-
tures of degenerative disc disease, the collapse was thought to
be traumatic in etiology.
Treatment/Management: He was discharged having re-
ceived corticosteroids.
Case 4.148
When the dog was presented four weeks later, it was ambula-
tory on its forelimbs only and the muscle wasting in the caudal
half of the dog’s body was severe. He had increased patellar ten-
don reflexes, but no positive pain perception in the pelvic
limbs. Additional radiographs of the L3–4 region were made.
Radiographic diagnosis (week 4): The widened disc space
was characterized by marked end plate destruction and sur-
rounding reactive new bone. The vertebral segments were
malaligned. The diagnosis changed from a traumatic luxation
to one of discospondylitis that was probably hematogenous in
origin.
Treatment/Management: Cultures of urine, blood, and tis-
sue obtained from the disc space under fluoroscopic control all
grew a penicillin-sensitive Staphylococcus aureus. The peripher-
al white cell count was increased.
The dog was treated with 1 gram oxacillin TID and remained
on that dosage for one month. This seemed to control the
spondylitis; however, the segmental malalignment remained
and the dog was eventually euthanized.
4
Day 1
Week 4

5.1 Introduction
The value of soft tissue radiography associated with traumatic
events is limited, but still remains rather interesting. An in-
crease in the size of soft tissue shadows can assume several
forms with either a generalized or focal swelling due to edema
or hemorrhage. The distribution of the fluid is generalized
when a distinct margin cannot be identified, and focal when a
sharply marginated soft tissue structure can be identified. A
decrease in the size of the soft tissue compartment is often
identified due to the disuse of a limb that has resulted in mus-
cle atrophy. If the accumulation of fluid is within a joint space,
a particularly well-defined margin is created by the distended
joint capsule. This is particularly evident adjacent to the
femorotibial joint.
Increases in density in the soft tissues are caused by the pres-
ence of soft tissue mineralization of various types ranging from
early calcification to mature bony tissue. Radiopaque foreign
bodies may have differing densities, but usually have a specif-
ic shape and margination that permits them to be differenti-
ated from the variety of soft tissue mineralizations. Debris on
the skin may appear to be located deeply within the muscle of
the limb on one radiographic view, but its true location can be
better determined by examination of the opposite view as
well. A physical examination of the limb prior to radiography
may save an erroneous radiographic diagnosis of penetrating
foreign bodies. The adherence of wet hair results in a rather
dense shadow on a radiograph. The application of a bandage,
cast, or splint generates shadows that are often specific and a
glance at the animal itself will offer an explanation of their
radiographic appearance.
The terms used in the description of soft tissue mineralization
can be confusing. Most post-traumatic lesions can be referred
to as dystrophic calcification or mineralization implying the
deposition of mineral within a damaged tissue. Calcinosis cir-
cumscripta is a term used to describe a particular form of ec-
topic mineralization. It is found as a focal lesion within the
subcutaneous tissues adjacent to joints, especially around the
feet, where it is thought to result from repetitive trauma lead-
ing to a dystrophic mineralization of the injured tissues. A spe-
cific form, tumoral calcinosis is characterized by the presence
of single or multiple, periarticular loculated cystic masses con-
taining chalky material thought also to result from repeated
trauma.
The quality of a radiograph taken for the identification of soft
tissue lesions can be improved by utilizing a lower kVp setting,
thereby making the study have a bit more contrast. It may help
to study the radiograph carefully with a bright light to insure
that the soft tissue portion is completely examined.
The most common foreign bodies in trauma patients in some
societies are those resulting from a gunshot wound and assume
a pattern typical for the gun that was used. The metallic mis-
siles range from “B-Bs” and airgun pellets, to multiple shot-
gun pellets, to the tract left by a rifle bullet in soft tissues. If
any of these projectiles strikes bone, the shape of the missile as
well as that of the bone can be markedly altered (see Chap. 6).
The metallic devices used for surgical reduction are expected
foreign bodies, but they should be studied to see whether they
have been properly implanted.
Puncture wounds into soft tissues caused by plant material or
wood can not be identified on a noncontrast study because the
foreign material has the same radiopacity as the surrounding
tissues The foreign material can often be identified on a radi-
ograph following the use of a contrast study of an associated
sinus tract. If the foreign body results in a tract formation, ei-
ther air or an iodinated contrast liquid can be injected into the
tract to permit its visualization on the radiograph. This may
then also identify the causative foreign body as well.
The identification of air within the soft tissues creates a less ra-
diodense shadow and attracts attention to the site of the injury.
It may be helpful in the identification of a foreign body or a
deeply seated injury, such as a soft tissue rupture or a fracture.
왘
487
5
Chapter 5
Radiographic Features of Soft Tissue Injuries

Case 5.1
Signalment/History: “Kelsey” a
3-month-old, female Labrador Re-
triever was presented with a com-
plaint of non-weightbearing on the
right thoracic limb. She had been
running in a field and stepped into a
hole and had been acutely non-
weightbearing since then.
Physical examination: Crepitus
was noted on movement of the right
elbow joint. Marked swelling was
present around the distal humerus.
Radiographic procedure: Radio-
graphs were made of the elbow
joint.
Radiographic diagnosis (day 1):
Radiolucent lines separated the lat-
eral condyle of the humerus with
the fracture lines extending into the
elbow joint.
Salter-Harris Type IV fracture was
repaired using a screw and 2 small
Steinmann pins. Anatomic align-
ment of the fragment was obtained.
Radiographic diagnosis (month
10): Radiographs made ten months
later showed the metallic implants to
have remained in the same position
with satisfactory healing of the frac-
ture without any apparent injury to
the growth of the bone.
A 3-cm-in-diameter, irregularly
mineralized mass arose from the lat-
eral aspect of the elbow. The mass
seemed to be related to the head of
the large bone screw, but no pe-
riosteal new bone could be seen.
The mass appeared to be flocculated
as though many pockets of calcified
tissue were present. This would fit
the diagnosis of tumoral calcinosis.
488 Radiographic Features of Soft Tissue Injuries
5 Day 1
Month 10

Case 5.2
Signalment/History: “Red” was a 7-year-old, male Ger-
man Shepherd who had suffered a shotgun injury to his distal
left forelimb.
Physical examination: The dog was lame on the left fore-
limb. His left elbow was swollen and painful on palpation. No
crepitus was noted and near full motion was possible.
left elbow, the antebrachium, and the foot.
Radiographic diagnosis: Two patterns of increased soft tis-
sue density were noted. One was a heavier pattern of small cal-
cified foci that was located lateral, caudal, and proximal to the
elbow joint. This pattern had sharp borders and all the foci ap-
peared rounded and were of uniform density. No bone or
joint injury was evident in connection with this pattern.
A more discrete second pattern of exactly the same size and
density was the result of the gunshot injury. It was distal and
was not associated with any fractures.
Differential diagnosis: The gunshot wound was thought to
be the cause of the lameness. The soft tissue mineralization was
chronic as evidenced by the discrete, well-marginated pattern.
Gravel or dirt if mixed with the hair coat or incorporated
within the skin following a “grinding” type of injury, might
have caused such a radiographic pattern.
Treatment/Management: No treatment was considered for
the shotgun wounds except to bandage the limb. Deep palpa-
tion of the skin and subcutaneous tissues around the elbow
joint identified the lesions seen on the radiograph. A careful
examination of the skin and subcutis indicated no debris of any
type.
Treatment of the soft tissue wounds resulted in their healing
and the case was lost to follow-up. Any clinical significance as-
sociated with the elbow lesions was not recognized.
Comments: The nomenclature for the type of chronic injury
seen in the soft tissues of the elbow is not well defined. Dys-
trophic calcification may be a good term since it suggests a
chronic injury with the development of multiple mineralized
nodules. Mineralization of a tendon can occur, although the
pattern seen in this elbow does not follow a tendon but re-
mains more subcutaneous. In comparison, myositis ossificans
suggests an injury leading to bone formation and is usually sit-
uated deeper in the muscle. Metastatic mineralization is more
generalized and is associated with chronic renal disease, hy-
perthyroidism, or hypervitaminosis D.
Case presentations 489
5

Case 5.3
Signalment/History: “Rommell” was a large, 8-year-old,
male mixed-breed dog with a history of having had a “trau-
matic” incident involving the tarsus one year earlier. The limb
had been placed in a cast for one month after the injury be-
cause of persistent lameness and pain. The owners presented
the dog for reexamination because of the continued lameness.
Physical examination: On presentation, “Rommell” was
definitely “favoring” his hindlimb. On palpation, the tarsal
region had a firm swelling and was painful on both palpation
and on movement of the joint.
Radiographic procedure: A series of radiographs was made
of the tarsal region.
Radiographic diagnosis: A pattern of soft tissue mineraliza-
tion on the dorsal aspect of the calcaneous in the region of the
attachment of the Achilles tendon created a cuff just proximal
to the bone (arrows). A pattern of periosteal new bone, prob-
ably enthesophytes, was noted as well. The joints were all nor-
mal in appearance.
Differential diagnosis: The pattern of mineralization with-
in the soft tissue and attached to the bone was typical of that
seen in a post-traumatic situation. The margination was sharp
and the density of the separate sites of mineralization was uni-
form. These two features suggested that the pattern not was re-
lated to either an acute or malignant process.
Treatment/Management: It was not thought that the
changes seen on these radiographs were the cause of the clini-
cal signs and radiography of the other major joints in the pelvic
limb was recommended as there was the possibility that addi-
tional damage had occurred at the time of the injury one year
previously. The owner chose not to spend any additional
money, and “Rommell” was discharged without a definite di-
agnosis and with no specific treatment recommended.
490 Radiographic Features of Soft Tissue Injuries
5

Case 5.4
Signalment/History: A 14-year-old, female Beagle who
had been a member of a colony was necropsied and radio-
graphed following death.
Radiographic procedure: Radiographs of the forelimbs
were a part of the total body radiographic study.
Radiographic diagnosis: Examination of the radiographs
indicated a soft tissue swelling on the dorsal and medial aspect
of the radiocarpal joint (arrows). Enthesophytes extending
from the distal radius were typical of those reported as a part
of the syndrome of stenosing tenosynovitis of the abductor
pollicis longus (APL) muscle. The changes were bilaterally
symmetrical.
Differential diagnosis: A single traumatic event might cause
enthesophyte formation. The finding of exactly the same pat-
tern of new bone on both forelimbs suggests a more chronic
repetitive movement possibly dictated by the manner of the
dog’s physical activities while being caged in the colony.
Comments: The most important pathogenic factors in the
etiology of a stenosing tenosynovitis of the APL are repetitive
movement and a sharp angulation of the tendon at the radial
styloid process. Overstraining of the tendon was probably due
to an overuse of the joint particularly as the colony dogs spent
a great portion of their day jumping against the enclosure’s
fence. While the primary radiographic feature was the bony
proliferation just proximal to the styloid process, it was the in-
flammation and stenosis of the tendon sheath that would have
impaired the free gliding movement of the tendon.
5

6.1 Introduction
Gunshot injuries can result from the patient being shot either
intentionally or accidentally. The frequency of gunshot
wounds is variable depending on the culture of the society. In
many patients, lead fragments or pellets are seen as incidental
findings and indicate previous trauma; however, animals may
be presented with acute gunshot trauma being the primary
complaint. The type of gunshot wound is variable. In rural or
hunting areas, shotgun and long-rifle injuries are encountered
with the greatest frequency. In metropolitan areas, handgun
and small-caliber gunshot injuries are more common. Guns
discharging a small pellet may be found in the hands of chil-
dren throughout the world.
The nature of the bullet or pellet varies with respect to size
and shape, the number of pellets, and the velocity of projec-
tile. The lowest velocity and the smallest pellet is the B-B and
consequently, it is the least damaging and is usually only an in-
cidental finding without clinical importance. However, if the
range is short, these pellets can cause fractures in the cat and
interestingly, can find their way into the spinal canal causing
serious injury to the spinal cord. A slightly larger pellet is used
in the air gun in which the velocity is greatly increased to such
a level that these pellets often cause fractures. A shotgun injury
varies depending on the size of the individual shot and the dis-
tance from the muzzle of the gun to the patient. Usually, these
are injuries of minimal severity; however, at short distances
they can be highly destructive to both soft tissues and to
bone/joint. A rifle bullet can vary not only in size or caliber,
but also with respect to the type of metallic coating, whether
the ”nose” of the bullet in pointed or flattened, and its veloc-
ity.
The extent of tissue damage inflicted by a bullet depends on
its velocity, mass, shape, composition, deformation (breakup),
aerodynamic stability (yaw), hydrodynamic stability (“tum-
bling” characteristic), and on the mass and blood supply of the
tissue traversed. Aerodynamic and hydrodynamic stability al-
ter the impartable energy. If the bullet loses its stability as it
travels through the tissue and begins to tumble rather than
maintain a longitudinal flight, the amount of energy imparted
to the tissue is increased. With low-velocity bullets, this in-
crease is small; however, with high-velocity missiles the ener-
gy transmitted is markedly increased over a short distance.
The energy available to inflict injury from a moving object is
related to the mass of the object times the velocity squared.
The velocity of the missile as it strikes and passes through tis-
sue is so important in influencing the wounding potential that
some researchers believe it alone may serve as an indicator of
the expected damage to the tissues. Traditionally, velocity has
been used to classify expected injury from bullet wounds into
high- or low-velocity injuries. A high-velocity bullet is classi-
fied as one that moves at a minimum rate of 600 to 750 m/sec.
Many handguns/pistols ranging from .22 to .45 caliber have
average velocities of 200 to 400 m/sec and are therefore con-
sidered low-velocity missiles.
The kinetic energy of high-velocity missiles is of such a large
magnitude that on striking a tissue they impart tremendous
energy to that tissue. When a bullet strikes a solid object such
as a bone, all or part of its kinetic energy is immediately trans-
mitted to the tissue. The resulting particles of bone accelerate
forward and act as secondary missiles. One of the primary fea-
tures of all missile wounds is cavitation. Within milliseconds
after a high-velocity missile impacts and perforates, a pulsating
undulating temporary cavity is formed. The surrounding tis-
sue is subsequently explosively pushed and compressed lateral-
ly to enclose the temporarily formed cavity. The maximum
diameter of this temporary cavity may be approximately 30
times the size of the original missile track. Therefore, tissues at
a distance from the original wound may be damaged and adja-
cent bones may be fractured without ever having been struck
directly by the missile or any secondary missile. In contrast,
lower-velocity missiles create a direct pathway of destruction,
with little injury to the surrounding tissues.
Bullet composition and design influence the extent of injury.
Bullets that undergo mushrooming expand to several times
their original caliber upon impact and establish a wound track
with a frontal area far exceeding 30 to 40 times that of a fully
jacketed, nonexpansile bullet, thereby increasing the wound
volume.
A bullet track can be identified on a radiograph through the
deposition of variously sized metallic fragments as the bullet
passes through the soft tissues. If the bullet is steel-coated or
has a hard coating of another type, there may be no fragmen-
tation and the soft tissue track cannot be identified on the ra-
diograph. A bullet tract may also be traced by a pattern of small
bone fragments that reflect the fractures that have occurred.
Clinically, it is important to determine the bullet track
through the patient’s body either radiographically or by phys-
ical examination, so that all organs suspected of being injured
can be identified and evaluated.
Classification of wounds can be made dependent on the ve-
locity of the missile. Low velocity wounds are common and
result from handguns or shotguns with velocities below 700
492 Radiographic Features of Gunshot Injuries
6
Chapter 6
Radiographic Features of Gunshot Injuries

Table 6.1: Radiograph features of gunshot injuries
1. B-B gun pellet
a. single pellet
b. remains spherical when striking soft tissues
c. deforms or breaks up when striking bone
d. low velocity
e. tissue injury
I. minimal
II. usually limited to soft tissues
2. Airgun pellet
a. single pellet
b. retains shape when striking soft tissues
c. deforms when striking bone
d. low velocity
e. tissue injury
I. usually limited to soft tissue
II. can fracture a small diameter bone when fired at close range
3. Shotgun pellets
a. multiple pellets
I. dispersion based on distance of the patient from gun
II. variation in size of pellets
b. coating
I. pellets remain spherical if steel-coated
II. pellets deform when they strike bone if they are lead
c. low velocity
d. tissue injury
I. based on size of pellet
II. based on pattern size (distance from muzzle of gun)
III. usually limited to soft tissue
IV. if dispersion is minimal can cause severe comminuted fractures
4. Rifle bullet
a. single bullet
b. appearance of bullet can
I. remain nearly unchanged
II. tumble or fragment
III. deform and fragment on striking bone
IV. expand and mushroom
V. leave a tract of small metallic fragments in soft tissue
c. velocity of missile ranges from high to very high
d. tissue injury
I. missile creates a direct pathway of destruction
II. high-velocity missile can
i) cause massive secondary injury due to cavitation
ii) accelerate bone fragments that act as secondary missiles
m/sec, while high-velocity wounds occur with velocities
above 700 m/sec and propagate stress waves and cavitation. A
penetrating wound is often the result of low-velocity missile
that is retained in the tissue and has a typically small and ragged
entry wound. A perforating wound is the result of a low- to
high-velocity missile, with the missile passing completely
through the patient. The exit wound is often considerably
larger than the entry wound. Elastic tissue such as fascia and
skin and spongy tissue such as lung show little devitalization
when traumatized by even high-velocity missiles. Soft, bulky,
homogeneous solid tissue such as muscle bellies, liver and
spleen are violently disorganized and devitalized by missile
wounds. Major vessel damage with a resultant compromising
of blood supply and expanding hematoma enhance the extent
of damage and the possibility of delayed healing.
Despite the potential for contamination associated with gun-
shot trauma, the results of a study have indicated a low preva-
lence of preoperative fracture contamination and postopera-
tive osteomyelitis. These results implied either a low contam-
ination rate or treatable contamination of the perifracture area
(Doherty and Smith 1995).
Gunshot injuries and their radiographic features are uniquely
dependent on the nature of the weapon (Table 6.1). An injury
resulting from a bullet from a high-powered rifle is very dif-
ferent from that resulting from a shotgun loaded with small
shot used for hunting birds. The distance of the dog from the
gun also obviously affects the severity of the injury. Usually,
these patients are presented as emergency cases and the owner
knows what type of injury it is. However, there can be a de-
lay in presentation if the owner is uncertain of the severity or
nature of the trauma; in such cases, learning of a gunshot in-
jury can come as a surprise.
References
Doherty MA/Smith MM. Contamination and infection of
fractures resulting from gunshot trauma in dogs: 20 cases
(1987–1992). JAVMA 206:203–205, 1995.
DiMaioVJM. Practical aspects of firearms, ballistics, and foren-
sic teachniques, CRC Press. 1999.
Kim PH. Gun Shot Wounds, University of Illinois-Chicago, Oral
and Maxillofacial Surgery. 2004.
Kolata RJ/Kraut NH/Johnston DE. Patterns of trauma in ur-
ban dogs and cats: A study of 1,000 cases. JAVMA
164:499–502, 1974.
Nunamaker DM. Open fractures and gunshot injuries. In: Text-
book of small animal orthopedics. Philadelphia: JB Lippincott
Co, 481–497, 1985.
Rendano VT/Abdinoor D. Management of intra- and extra-
articular extremity gunshot wounds. JAAHA 13: 577–581,
1977.
Schwach RP/Park RD/Piermattei DL etc. Gunshot fractures
of extremities: classification, management, and complica-
tions. Vet Surg 8:57–62, 1979.
왘
Introduction 493
6

Case 6.1
Signalment/History: “Sadie” was a 4-year-old, female
mixed-breed Retriever with a habit of chasing sheep in the
neighbor’s pasture. When the owner found “Sadie”, she had
severe skin injuries on the right side of her body.
Radiographic procedure: Both the thorax and abdomen
were radiographed to determine the extent of the injury.
Radiographic diagnosis (thorax):A pulmonary infiltrative
pattern was located primarily in the cranial lung lobes. A
pneumothorax was bilateral with air that appeared to be both
free in the pleural space as well as being trapped. Separation of
the cardiac silhouette from the sternum was the result of the
pneumothorax. Pleural fluid was prominent and was assumed
to be the result of hemorrhage. Two intrathoracic metallic pel-
lets were identified. The pulmonary vessels were small, sug-
gesting shock. Subcutaneous emphysema was evident within
the right chest wall.
6

Radiographic diagnosis (abdomen): Poor serosal contrast
was assumed to be due to peritoneal fluid, most likely peri-
toneal hemorrhage. Free peritoneal air was within small cran-
ioventral pockets and in the midabdomen. Multiple metallic
pellets were identified; some fragmented. The subcutaneous
emphysema extended along the right abdominal wall. A sus-
pected fracture in the right 13th rib was near the costovertebral
joint.
Differential diagnosis: The peritoneal fluid in a gunshot
would could have been: (1) hemorrhage, (2) infectious peri-
tonitis associated with perforated bowel, (3) bile peritonitis as-
sociated with liver and/or ball bladder injury, or (4) urine as-
sociated with rupture of the bladder. The small pockets of
peritoneal air suggested bowel perforation with the probabili-
ty of peritonitis.
A pattern of pellets from a shotgun could be seen in both the
thorax and abdomen. Note how one of the pellets fragmented
because it had struck the spine at L1–2.
Hemorrhage in both the pleural and peritoneal cavities was
seen in association with both pleural and free peritoneal air.
Treatment/Management: “Sadie” underwent an ex-
ploratory laparotomy and 40 cm of small bowel with its
accompanying mesentery were removed. Seven sites of in-
testinal perforation were located. “Sadie” was released from
the hospital several days postsurgery.
6

Case 6.2
Signalment/History: “Shadow” was a 5-year-old, male
Labrador Retriever who had had bilateral pectinotomy sur-
gery two years previously in an effort to relieve the pain from
bilateral hip dysplasia. He was presented at the clinic because
right pelvic limb lameness had persisted.
Physical examination: Palpation of both hip joints was
painful and showed limited motion of the joints.
Radiographic procedure: A single VD pelvic radiograph
was made.
Radiographic diagnosis: Bilateral femoral head subluxation
and remodeling of the acetabulae, and the femoral heads and
necks were diagnostic of severe secondary joint disease due to
hip dysplasia. Superimposed over the joint disease were mul-
tiple metallic densities indicative of a shotgun injury due to
small “bird shot”. The dispersion of the shot was small indica-
tive of close range and was primarily on the left side.
Treatment/Management: Secondary arthrosis of this
degree in a 5-year-old was not thought to be amenable to
surgical correction except through the use of a total hip re-
placement. The owner chose that the dog be treated with con-
servative therapy instead.
Comments: The clinical signs of pain and lameness were due
to the arthrosis. While the shotgun injury made an impressive
radiographic pattern, it was considered an incidental finding,
especially considering the small size of the pellets.
The lead shield was placed over the gonads to provide protec-
tion from the primary radiation.
6

Case 6.3
Signalment/History: “Tanker” was a 1-year-old, male
Doberman Pinscher who had been shot the previous evening.
The owner said that the dog was very close to the gun at the
time of the shooting.
Physical examination: The left elbow appeared to have
been almost destroyed by the injury.
left forelimb.
Radiographic diagnosis: A fracture of the distal humerus
included a 2- to 3-cm-long butterfly fragment. Fracture lines
were not identified entering the elbow joint. The metallic
fragments were grouped medially around where the soft tissue
injury appeared the most severe. No apposition of the bone
fragments was present.
Treatment/Management: The fracture was first treated
with an external K-E apparatus that was followed by place-
ment of a bone plate. Healing was complicated by chronic os-
teomyelitis. The last study was done nine months after the in-
jury. At that time, the elbow had undergone bony fusion and
heavy callus formation was evident around the fracture site.
Osteomyelitis was evident and several of the bone screws had
loosened. The patient was lost to further follow-up.
Comments: Typically, a shotgun causes a low-energy injury.
However, if the distance is short as in this patient, the con-
centration of the pellets creates a high-energy type of injury.
Note that the fracture is proximal to the site of entry of the
pellets. This is more typical of the type of injury seen with a
very high velocity rifle bullet.
6

Case 6.4
6

Signalment/History: “Star” was an 11-month-old, male
English Pointer who had suffered an injury to the head and left
forelimb from being accidentally shot by his owner.
Physical examination: The injury to the head was easily de-
tected. The fractures of the radius and ulna could be palpated.
Radiographic procedure: The dog was anesthetized and ra-
diographs were made of the head, since it was thought that that
injury was of greater clinical importance. Radiographs of the
forelimb were delayed.
Radiographic diagnosis (head): Multiple metallic pellets
were scattered within the nasal region without evidence of
fracture. One pellet was within the left periorbital space as
identified on the open-mouth view and several pellets were
within the tongue. Many of the pellets were malformed, indi-
cating that they had struck bone, while others left a trail of
small metallic debris suggesting that the pellets were made of
soft metal.
An increase in fluid density in the left nasal passages suggested
hemorrhage at this location. The frontal view was especially
important in the evaluation of the frontal sinuses showing that
they were clear and without hemorrhage. Note the string ad-
jacent to the canine teeth on the open-mouth view used to
position the head on the tabletop.
Treatment/Management: None of the metallic pellets in
the head were in a location suggesting the need for surgical
removal. Examination of the eye was considered especially
important as one of the pellets was in the periorbital space;
however, no signs of injury to the eye were noted on clinical
examination. The injuries to the head were treated in a
conservative manner. The forelimb fractures were successfully
reduced and stabilized and the dog discharged.
The fractures healed slowly because of the extensive soft tissue
damage, but “Star” was eventually able to work in the field
again.
Comments: The injury was typical of that resulting from be-
ing shot by a shotgun. The major force of the trauma was to
the left forelimb, with the head located at the periphery of the
shot pattern. Multiple views were required to access the head
completely, and the study required use of an anesthetic.
6

6

Case 6.5
Signalment/History: “Skinny” was an 11-month-old, male
Doberman Pinscher who was presented with a swelling
around the horizontal ramus of the left mandible of unknown
origin. The swelling had remained the same size for the previ-
ous four weeks. He was able to eat, although the owners ad-
mitted that they fed the dog outside and did not watch him
closely while he was eating.
The lesion had been treated surgically with placement of a se-
ton to encourage drainage. Antibiotic therapy had been tried.
It was assumed that the lesion was subsequent to some type of
trauma or plant awn (fox tail) migration.
Physical examination: On external palpation at the time of
admission, the lesion was firm and not painful. The gingiva
were intact and all the teeth appeared to fit tightly in the alve-
oli. The dog did not permit the mouth to be opened fully.
head with special views of the left mandible centered on the
site of swelling.
Radiographic diagnosis: A healing fracture of the horizon-
tal ramus of the left mandible at the level of the first molar had
a large bridging callus orally and ventrally. The fracture was
chronic and thought to be the result of a gunshot wound on
the basis of identification of the tract of metallic fragments at
the fracture site, plus a single centrally located large metallic
fragment. The fracture line remained open with a central ra-
diolucent zone that was presumed to be infected with the area
of osteomyelitis surrounded by a heavy involucrum (callus).
Small bony fragments were presumed to be sequestra. Addi-
tional metallic fragments were present within the adjacent gin-
gival tissues and within the tongue.
Differential diagnosis: The differentiation between a de-
layed union of a fracture because of a lack of stabilization of
the major fragments and the presence of the metallic frag-
ments, and a potentially non-union fracture because of a su-
perimposed infection was not possible. The radiolucent zone
strongly suggested an osteomyelitis.
Treatment/Management: Even though the lesion was sol-
id at the time of surgery, the center was curetted, removing
what appeared to be dead bony tissue and the large metallic
fragment. Subsequent radiographs showed bony healing across
the fracture site.
Comments: Treatment of the delayed-union fracture as if it
was infected was the safest route, and it was thought that the
surgical curettage would be beneficial in achieving rapid frac-
ture healing.
This case is most interesting in that the owners admitted to
knowing nothing about the injury and little about the dog’s
eating habits during the period of time after the trauma sug-
gesting that clinical histories that accompany the patient to the
clinic are often questionable in their accuracy.
6

Case 6.6
Signalment/History: “Rex” was a 1-year-old, male
Labrador Retriever with a gunshot wound in his right axilla
and left pectoral region, as well as a fracture in the left ante-
brachium.
Physical examination: The examination was limited be-
cause of the injuries; however, the fractures in the left forelimb
were easily noted.
Radiographic procedure: The thorax was radiographed to
show the extent of the injury from the gunshot, and especial-
ly included the thoracic inlet. A study was also made of the left
antebrachium.
Radiographic diagnosis (day 1, thorax): An extensive
pulmonary hemorrhage within the cranial lung lobes had a su-
perimposed pattern characterized by patchy air-filled cavities
in the tip of the right cranial lobe that were suggestive of se-
vere lung parenchymal damage, similar to that seen following
trauma-induced pneumatoceles. A marked air-bronchogram
pattern was seen in the cranial lobes.
A right-sided pneumothorax could be seen between the col-
lapsed cranial and middle lobes and the thoracic wall. The
pneumothorax also resulted in elevation of the cardiac silhou-
ette. Minimal pleural fluid probably representing hemorrhage
was seen throughout the thoracic cavity. Note how the fluid
within the lung plus the pleural fluid created a fluid-like den-
sity that caused silhouetting with the heart shadow cranially.
6
Day 1, thorax

Radiographic diagnosis (day 5, thorax): Marked clearing
of the pulmonary hemorrhage was noted on this study; how-
ever, persistent air-bronchograms in the peripheral lung lobes
cranially, indicated a slower healing of the more severely dam-
aged lung. Resolution of the pneumothorax and the pleural
hemorrhage was noted.
왘왘
6
Day 5, thorax

Radiographic diagnosis (day 1, antebrachium): A mid-
shaft, complete, transverse fracture of the left radius plus an in-
complete, mid-shaft fracture of the left ulna had associated
bullet fragments in the surrounding soft tissue of the left ante-
brachium. Subcutaneous air was present in the left antebrachi-
um plus a soft tissue pattern due to a wet hair coat. The elbow
joint and antebrachiocarpal joint were normal.
Radiographic diagnosis (day 6, antebrachium): Reduc-
tion of the radial fracture using a five-hole bone plate was car-
ried out on day 6. The ulnar fracture was now complete with-
out fragment apposition. The larger metallic fragment had
been removed. The placement of a rubber drain caused a
prominent water-dense shadow dorsally and medially.
6
Day 1, antebrachium Day 6, antebrachium

Radiographic diagnosis (day 90, antebrachium): The
healed radial fracture and a malunion healing of the ulnar frac-
ture were noted. Small metallic fragments remained adjacent
to the fracture site.
Comments: The injury to the lungs and delay in healing was
typical of a bullet wound and different from that expected
from blunt trauma seen when a dog has been struck by a car.
Interestingly, the bullet had entered the body near the right
axilla, passed through the cranial thorax where it caused injury
to the right lung lobe. It then exited the left chest wall cran-
ioventrally and entered the left forelimb fracturing the radius
and ulna.
Note how the bullet had lost most of its energy upon entering
the forelimb and the large metallic bullet remained adjacent to
the fractured bones. The radiographic features of healing of
the well-stabilized radial fracture can be compared to the fea-
tures of delayed healing seen in the ulnar fracture in which the
fragments were left unapposed and without solid fixation.
6
Day 90, antebrachium

Case 6.7
Signalment/History: “Roscoe” was a 5-year-old, male
Labrador Retriever who had been injured in the morning by
either being struck by a car or shot.
Physical examination: He was in shock on presentation.
Radiographic procedure: A series of thoracic radiographs
were made to show the progression of changes associated with
the trauma.
Radiographic diagnosis (at time of admission, thorax):
The injury had caused hemorrhage within the left cranial lung
lobe resulting in a prominent air-bronchogram pattern along
with mediastinal widening suggestive of hemomediastinum.
No injury was noted in the thoracic wall. The pleural space
was normal with no free air or fluid. Soft tissue swelling
around the right shoulder could be seen. The injury was more
suggestive of a puncture wound such as might follow a gun
shot injury rather than that following blunt trauma.
6
At time of admission

Radiographic diagnosis (3 hours post admission, tho-
rax): A second set of thoracic radiographs were made three
hours later and showed a minimal clearing of the fluid from
the left lung; however, air bronchograms persisted. The vol-
ume of mediastinal hemorrhage had decreased slightly. Mini-
mal pleural fluid was now noticeable.
왘왘
6
3 hours post admission

Radiographic diagnosis (6 hours post admission, tho-
rax): A third set of thoracic radiographs made after another
three hours showed a persistence of the mediastinal hemor-
rhage. The pleural hemorrhage had increased in volume. Air
bronchograms persisted in the left cranial lobe.
Treatment/Management: Bullet entry and exit wounds
were identified on both fore limbs. The dog was treated with
blood transfusions. Pressure bandages were placed in the right
axilla. The injury was thought to involve the right brachial
plexus.
6
6 hours post admission

made five days later showed persistent mediastinal hemor-
rhage. The left cranial lung lobe had re-inflated and had re-
gained normal tissue density. A lesser amount of pleural fluid
was evident.
Treatment/Management: The patient was discharged and
not seen on follow-up.
Comments: The pattern of hemorrhage within the medi-
astinum and lung was typical of that seen in a patient shot by
a rifle. The bullet did not strike bone so a pattern of metallic
fragments could not be identified. The cardiac silhouette was
slightly enlarged on all the studies and the possibility of hemo-
pericardium was considered.
6
Day 6

Case 6.8
Signalment/History: “Blue” was a 3-year-old, female Ger-
man Shepherd who had been found that morning with a se-
vere injury to the distal portion of her left pelvic limb thought
to be from a gunshot.
Physical examination: Examination was limited because of
the extensive tissue injury. Palpation suggested that the foot
was attached to the upper limb by soft tissues alone, since no
crepitus was noted.
Radiographic procedure: Two views were made of the
pelvic limb.
Radiographic diagnosis: A gunshot injury from a very high
energy bullet had destroyed a segment of the distal tibia, and a
large portion of the soft tissue was missing, too. The commin-
uted fracture extended proximally to the midshaft of the bone
and distally just proximal to the apparently unaffected tibio-
tarsal joint. No apposition of the fragments was present.
The very high energy bullet had a coating that had not frag-
mented and no metallic fragments could be identified within
the soft tissues.
Treatment/Management: The owner was advised that the
limb could not be salvaged and amputation would be neces-
sary. The owners did not want a “Blue” with only three limbs
and she was euthanized.
Case 6.9
Signalment/History: “Russell”
was a 5-year-old, male mixed-breed
Labrador Retriever, who had re-
ceived a gunshot injury some
months previously. He had been
lame at that time, but was not pre-
sented for treatment and the owner
admitted knowing little about the
trauma. On the day of presentation,
the pelvic limb lameness had re-
curred. It was more severe in the
mornings and after resting. He
seemed to “warm-out” of the lame-
ness.
Physical examination: Palpation
of the hips produced signs of joint
laxity bilaterally, but the extent of
motion of the pelvic limbs was
6

thought to be normal. No evidence of muscle atrophy was
noted. Pain was not detected, although dogs of this age and
breed are often stoic.
Radiographic procedure: Ventrodorsal and lateral views
were made of the pelvis with a special view of the left hip joint
after review of the first radiographs.
Radiographic diagnosis: The radiographs showed bilateral
femoral head subluxation (hip dysplasia) with no evidence of
secondary bony changes. A rifle bullet was lodged in the soft
tissues adjacent to the lesser trochanter on the left. The lesser
trochanter was fragmented. An adjacent 2-cm-in-diameter
fragment of bone density was thought to represent a fracture
fragment or a soft tissue calcification that had remodeled, re-
sulting in a smooth margin suggestive of chronicity.
Treatment/Management: The left hip joint had not been
injured by the bullet. The metallic foreign body was not in-
traarticular and thus thought not to be clinically important at
this time. Replacement of the fracture fragment was not con-
sidered possible nor required.
The pain from the hip dysplasia and from the soft tissue injury
was not treated. The owner was advised to carry out limited
exercise and control the dog’s weight. The owner was also told
that minimal trauma to hip joints of this character can produce
pain and so cause clinical signs.
Comments: The injury to the lesser trochanter produced
sufficient soft tissue injury to cause a secondary pattern of cal-
cification and subsequent ossification. The absence of muscle
atrophy suggested that no limitation of usage of the limb
existed. The femoral head luxation was thought to be a part of
bilateral hip dysplasia; however, the absence of secondary bony
changes in a 5-year-old patient with dysplasia was thought to
be unusual.
6

Case 6.10
Signalment/History: “Claire” was an 8-month-old, female
Labrador Retriever who was presented with bleeding from
wounds in the right pelvic limb. Two sites of injury were iden-
tified suggesting an entry and an exit wound.
Physical examination: The patient was in hypovolemic
shock, but her breathing was thought normal. The pelvic limb
wounds were easily identified and radiographs were ordered.
pelvis and both femurs.
Radiographic diagnosis: The soft tissue injury in the pelvis
was on the right. It was severe, with swelling and a dissemi-
nated pattern of gas within the soft tissues. Several small metal-
lic fragments could be seen lying deep within the muscles and
suggested a high-energy gunshot injury. No fractures were
identified and neither the hip nor stifle joints had been injured
by the gunshot.
Abdominal radiographs were made and the bullet was identi-
fied within the right cranial abdomen.
Differential diagnosis: Often debris on the skin creates soft
tissue patterns in trauma patients. In “Claire”, the location of
the metallic fragments and gas was not on the surface, but deep
within the muscle mass; a pattern more typical for a puncture
wound such as a gunshot wound. The additional radiographs
located the bullet.
Treatment/Management: Exploratory surgery of the ab-
domen surprisingly confirmed a healthy status of the bowel
without excessive peritoneal hemorrhage.
The injury to the arterial supply of the femoral limb was of
concern, but the patient healed successfully and was released
from the clinic.
6

Case 6.11
Signalment/History: A 2-year-old, male mixed-breed dog
was presented because he could not walk normally. The own-
ers knew nothing concerning the cause of the lameness.
Physical examination: The limb was swollen with skin le-
sions around the carpus. Palpation of the distal antebrachium
was painful and crepitus was detected.
antebrachium.
Radiographic diagnosis: A comminuted fracture of the dis-
tal radius with associated metallic fragments suggested injury
from a high energy rifle bullet (arrows). Cavitation had oc-
curred at the time of the injury. The fracture was distant from
the bullet tract, with one fracture line entering the radiocarpal
joint. The radial carpal bone was displaced medially resulting
in a radiocarpal luxation suggesting destruction of the medial
collateral ligament. The lateral portion of the articular surface
could not be identified, but was thought to be injured.
A clinically unimportant airgun pellet in the soft tissues lay ad-
jacent to the cranial radial epiphysis.
Treatment/Management: The owners chose not to have
the patient treated.
6

Case 6.12
6

Signalment/History: “Buddy” was a 6-month-old, male
German Shepherd unable to open his mouth to eat.
Physical examination: Swelling in the region of the left
mandible was evident, however, a site of soft tissue injury was
not noted. The mandible was painful on palpation, but no
crepitus was detected. No abnormalities were evident on oral
examination.
head with special oblique views of the site of swelling on the
mandible.
Radiographic diagnosis: A gunshot wound characterized
by the deposition of small metallic fragments along the bullet
tract had caused an incomplete fracture of the left mandible
just cranial to the angular process. The tract continued later-
ally causing soft tissue injury in the laryngeal region. The
metallic pattern could be identified more clearly on the en-
larged figures.
Treatment/Management: The fracture was not complete
and required no fixation. The full importance of the soft tis-
sue wound could not be determined from the radiographs.
The dog was examined and found to be able to swallow nor-
mally. He was kept on a liquid diet for some days and subse-
quently released to his owner.
Comments:The fracture was typical of one resulting from an
injury due to a high-energy rifle bullet. The tract could be
identified along with the fragments that had resulted when the
bullet struck the mandible. Removal of the metallic fragments
was not required.
6

Case 6.13
Signalment/History: “Jinx” was a 4-year-old, female Ger-
man Shepherd with bleeding around the head. The owners
thought it was from a gunshot because they had heard shoot-
ing just before finding the dog injured.
Physical examination: The soft tissues on the right side of
the head including the external ear were badly damaged. No
effort was made to palpate deeply to determine the presence
of bony lesions.
Radiographic procedure: Routine lateral and VD studies
were made of the head with the dog awake.
Radiographic diagnosis: The metallic fragments associated
with the bullet tract were located on the right side of the head
and neck dorsally. The caudal portion of the zygomatic arch
had been destroyed by the bullet. The normally air-filled ex-
ternal ear canal on the right could not be identified. The bul-
let tract appeared to be just dorsal to the temporomandibular
joint, which was unaffected. The largest metallic fragment was
located in the soft tissues dorsal and to the right of the second
cervical segment.
Treatment/Management: The owners chose not to have
the dog treated.
Comments: The radiographic presentation of the injury was
typical of that resulting from a gunshot wound from a rifle
bullet. When, as in this case, the path of the bullet is unknown,
it is advisable to radiograph a larger area than usual to insure
location of the bullet and detection of the entire bullet tract.
6

Case 6.14
Signalment/History: A mature Siamese cat had been found
lying in the street unable to walk and was brought to the clin-
ic.
Physical examination: The right forelimb was fractured.
right forelimb.
Radiographic diagnosis: A gunshot wound in the right
forelimb had caused a comminuted fracture in the midshaft of
the humerus with marked overriding of the bone fragments.
The injury appeared acute. Some metallic fragments were at
the fracture site, but the largest part of the bullet lay within the
cranial thorax ventrally (arrows).
Treatment/Management: After the diagnosis of a gunshot
injury, additional thoracic radiographs were made to evaluate
the full damage caused by the bullet. Although it was lying on
the floor of the thoracic cavity, it did not appear to have
caused any injury to the surrounding organs. The humeral
fracture was treated successfully.
Comments: The gunshot wound was typical of that seen
with a rifle bullet; however, it must have been fired at a great
distance since the bullet passed through only a minimal tissue
thickness before coming to rest in the thoracic cavity. An air-
gun pellet does not deform, as has this bullet.
Aging this bullet wound was difficult because it was impossi-
ble to know if the indistinct appearance at the fracture site was
because of the comminution or because of an early callus for-
mation.
6

Case 6.15
6

Signalment/History: “Gabriel” was a 3-year-old, male
Labrador Retriever with a history of having been shot in the
pelvic region four months previously. The hip had been oper-
ated on at that time, although the exact nature of the surgical
procedure was not known.
Physical examination: Marked soft tissue atrophy was evi-
dent around the pelvis on the right without any evidence of
skin lesions. Crepitus was prominent upon movement of the
right pelvic limb. The lameness was not associated with pain
and neurologic injury to the limb was thought possible.
made.
Radiographic diagnosis: A gunshot injury from a high-
energy rifle bullet had resulted in fragmentation of the right
femoral head with bony fragments evident within the aceta-
bulum. Metallic fragments surrounded the hip joint. The
right femoral head was luxated dorsally and was forming a
pseudoarthrosis. A portion of the femoral head was missing
presumably having been removed surgically.
The left femoral head sat well within the acetabulum; how-
ever, an enthesophyte was present on the femoral neck. The
stifle joint was normal.
Radiopaque suture material indicated earlier soft tissue repair.
Treatment/Management: Surgery was scheduled to ex-
plore possible injury to the sciatic nerve. The nerve injury was
identified but the attempted repair of the sciatic nerve proved
to be unsuccessful.
Comments: Radiographs of a post-traumatic injury with a
superimposed surgical trauma are difficult to evaluate. Osteo-
lysis of the bone fragments and the remaining portion of the
femoral head could have been the result of disuse or could have
represented bone infection.
6

Signalment/History: “Shilow” was a 2-year-old, male
mixed-breed dog, who lived in the foothills and was free to
roam. He returned home one evening with a depressed ex-
pression and did not want to move his tail.
Physical examination: Swelling was noted around the right
stifle joint with pain on palpation. Movement of the tail indi-
cated a questionable region that had excessive movement and
possible crepitus.
Radiographic procedure: Two views were made of the tail.
Radiographic diagnosis: A comminuted fracture of the 8th
coccygeal vertebra was compressed with marked shortening of
the segment. Multiple metallic fragments surrounded the frac-
ture site suggesting a gunshot wound. The trabecular frag-
ments were indistinct and it was not possible to determine the
age of the fracture, the presence of early callus, or the presence
of bone infection. The distal endplate was fractured probably
indicating injury to that disc while the cranial disc appeared
within normal limits. Soft tissue swelling was prominent.
Radiographs of the stifle joint showed the presence of a single
metallic shot in the soft tissues lateral to the joint.
Case 6.16
Treatment/Management: The largest metallic fragment
was removed surgically from the tail, although this was prob-
ably not necessary. It was not possible to stabilize the fracture
and, in fact, palpation suggested that the fracture site was rigid
and was of some duration with formation of an early callus.
Radiographs made two weeks later showed further callus for-
mation and no evidence of destructive changes suggestive of
bone infection.
6

Case 6.17
Signalment: A 10-month-old male Siamese cat was received
in the clinic with a shoulder wound of 5 days duration that was
of unknown origin.
Physical examination: The soft tissue wound in the region
of the shoulder was complicated by the detection of pelvic
limb paresis with exaggerated spinal reflexes and reduced re-
sponse to pain sensation. Discussion with the owner suggest-
ed that the neurological signs were progressive during the 5
days.
Radiographic Procedure: Lateral and ventrodorsal views
were made of the spine. (Views of the lumbar spine were in-
cluded.)
Radiographic Diagnosis: A radiopaque foreign body (ar-
rows)was clearly identified in the lumbar spine. Examination
of both orthogonal views proved that the gunshot pellet was
lodged within the spinal canal. Careful examination indicated
that bone fragments originating from the dorsal laminae were
located adjacent to the bullet within the spinal canal.
Comment: Loss of deep pain sensation occurred shortly fol-
lowing the examination and the cat was euthanized.
6

Case 6.18
Signalment: An 8-year-old male Labrador Retriever was
presented having been accidentally shot by the owner.
Physical examination: The neurological signs were indica-
tive of a cauda equina syndrome and radiographic studies were
ordered.
Radiographic procedure: Two views of the lumbosacral re-
gion were made.
Radiographic diagnosis: Major bony disruption was not
evident. However, what was important was a pathway made
by a bullet leaving small metallic fragments that extended lat-
erally at the level of the lumbosacral disc and at the level of the
spinal canal (arrows). The result was destruction of the con-
tents of the spinal canal at the level of the lumbosacral junc-
tion. Incidental findings were hip joints thought to be near-
normal in conformation and minimal spondylosis deformans
at the LS disc. The dilated status of the rectum was in agree-
ment with the neurological injury.
Comments: The owner refused treatment and the dog was
euthanized.
6

7.1 Introduction
The following narrative explains somewhat the change in atti-
tude that has taken place since the first realization that abuse
could be associated with some of the so-called trauma cases
seen in a veterinary clinic.
“I remember the radiographs of the dog, his name was “Bob-
by”, because we used the study every year for the annual spring
university picnic. The Veterinary School furnished a radio-
graphic exhibit of cases that would be of interest to kids. What
could be more interesting than a dog that had “swallowed” a
large metallic spoon? Later, we added to the exhibit other cas-
es of interest. One was the cat with a needle embedded in the
caudal nasopharynx. It was rusty and you could see the rough-
ened surfaces. Then we added lateral radiographs of the thorax
and abdomen of a large lion that had over 300 air-gun pellets
within and under its skin. Two cases of cats with rubber bands
around a foot and around the mandible were not as attractive,
since they only caused a focal osteomyelitis, where the foreign
body had cut through the soft tissue and come to lie next to the
bone. We didn’t include the radiographs of the pelvis of hunt-
ing dogs that had been shot in the course of their field activities
because these cases were so common. Another case that was of
interest to the rodeo fans was the young bull calf that had wire
wrapped around its foot to generate pain, so the animal was eas-
ier to control. The only problem was that everyone had forgot-
ten about the wire, and it was soon covered with hair and skin.
All that remained was a huge, hard, swollen pastern joint with
a massive periosteal new bone formation and periarticular
ankylosis of the joint plus the wire.”
Unfortunately, the veterinarian is faced with cases of this type
rather frequently and they constitute several distinct problems.
The first, and easiest to handle, is characterized by the owner
of a large cat; who, by the way, did have a state permit to have
such animals in a “private zoo”. He readily admitted having
shot the cat repeatedly, using it as a technique to “attract the
cat’s attention”. He was somewhat embarrassed to realize that
the pellets did not just bounce off the skin, but actually em-
bedded and were probably painful. The hunters whose dogs
are frequently shot are usually a group, who in anger or frus-
tration, fire the gun with the thought that they may thereby
correct aberrant behavior on the part of the dog. The owners
of the young bull calf were just forgetful. Adults can usually be
talked to and shown how their animal or pet has been injured.
What may be of greater importance is the bringing to the at-
tention of the owner of a patient in which the injury is more
likely to be malicious and may be performed by a child with-
in the household.
A recent article in The Forensic Examiner was entitled “Kids
Who Kill”. It stressed the relationship of attachment disorder,
antisocial personality, and violence. “Cruelty to animals is one
of the most disturbing manifestations of attachment disorder. It
ranges from annoyance of family pets (e.g., tail pulling, kicking)
to severe transgressions (e.g., strangulation, mutilation).”
These children lack the capacity to give and receive affection
with pets, lack the motivation to provide appropriate care, and
delight in venting their frustrations and hostilities on helpless
creatures to compensate for their own feelings of powerlessness
and inferiority. Studies have found that children who abuse an-
imals are five times more likely to commit violent crimes as
adults (Levy and Orlans 1999). A majority of individuals who
have committed multiple murders have also admitted to cruel-
ty to animals during childhood (Cannon 1997). It should also
be borne in mind that children who are sadistic are usually
themselves the victims of cruel treatment (Fromm 1973).
What are the solutions open to the veterinary clinician, who
during the examination of a pet, finds evidence of animal
abuse (radiology is obviously only one method of making this
determination). Remember that the clinician may only be sus-
picious of abuse, certainly does not know if it was committed
by a family member, and does not want to risk losing a client
by making a suggestion that may be totally rejected. However,
the clinician may be the only person who is in a position to
identify a disturbed child and interrupt what might be a path-
way to further cruelty to animals. Remember that children
with severe attachment disorders commonly manifest the
three symptoms that are also found in the childhood histories
of adult psychopaths: cruelty to animals, enuresis, and fire set-
ting (Levy & Orlans 1999).
Please consider the following: talk to the owner of the pet and
suggest that their animal may have been the subject of abuse.
Let them know that this is not just a childish prank. Ask for
their support. Make a report to child protective services if this
option is open.
References
Cannon A. Animal/human cruelty linked. Denver Post, August
10, 1997.
Fromm E. The anatomy of human destructiveness. New York:
Holt, Rinehart and Winston, 1973.
Levy TM/Orlans M. Kids who kill. The Forensic Examiner
pp 19–24, March/April 1999.
왘
523
7
Chapter 7
Radiographic Features in Cases of Abuse

Case 7.1
Signalment/History: “Geben”, was a 1-year-old, male,
German Shepherd mixed breed, who was radiographed after
having been hit by a car three days earlier. He was lethargic,
dehydrated, and icteric upon physical examination.
Physical examination: The dog was lame in the hindlimbs;
however, no pain was detected on palpation and the hip joints
palpated easily.
pelvis because of the dog’s breed and the lameness noted in the
examination room.
Radiographic diagnosis: A metallic foreign body (arrow)
was noted dorsal to the right hip joint (a broken needle). The
hip joints were not positioned perfectly, but no signs of dys-
plasia were noted.
Treatment/Management: “Geben” was treated for the sys-
temic signs and recovered. The needle was not painful on
deep palpation over the hip joint and no effort was made to
remove it.
Comments: The origin of the metallic foreign body was un-
known, but its location plus the fact that it was broken sug-
gested that this was an example of abuse to a dog.
524 Radiographic Features in Cases of Abuse
7

Case 7.2
Signalment/History: “Lassie” was a 14-month-old, female
Collie with a history of sneezing both mucus and blood from
both nostrils. The duration of the signs was not known by the
owners. This was surprising to the clinician considering that
the owners admitted that the dog was in the household regu-
larly and the sneezing would have caused the surroundings to
be rather badly soiled.
Physical examination: The nasal discharge was evident. No
abnormality was noted during the examination of the head
and neck, although it was limited because the dog was unco-
operative.
Radiographic procedure: Studies were made of the head
primarily for the nasal passages; however, open mouth studies
could not be made.
Radiographic diagnosis: A metallic needle was clearly
demonstrated within the turbinates. A little inflammatory re-
sponse could be identified surrounding the foreign body.
Note the shadow cast by the clasp on the dog’s identification
band.
7

Case 7.3
Signalment/History: “Tiger” was a 3-year-old, male Point-
er with a history of “pawing” at his face for the previous few
days.
Physical examination: He refused to permit a thorough ex-
amination of his head; however, no nasal discharge was noted.
head including special views of the nasal cavity.
Radiographic diagnosis: A metallic foreign body (sewing
needle) was located in the right nasal cavity. It had obviously
been forced through the hard palate where the head of the
needle still remained. The study shown here includes the
placement of an intraoral location needle (arrow).
Comments: The second needle was positioned intraorally as
a location needle prior to an attempted surgical removal.
7

Case 7.4
Signalment/History: “Schlutzie” was a 7-year-old, male
Dachshund who had had a sudden onset of dysphagia 12 hours
previously, refusing food and making frequent swallowing ef-
forts.
Physical examination: He was uncomfortable in the exam-
ination room and made grunting sounds. He refused to eat
food when it was offered and would not open his mouth wide-
ly. Sub-mandibular soft tissue swelling was evident. A com-
plete oral examination was difficult and was delayed until the
radiographs were made.
Radiographic procedure: Routine lateral and DV radio-
graphs were made of the head and neck as a survey study. The
radiographic exposure was decreased slightly so that the soft
tissues could be evaluated better.
Radiographic diagnosis: A slightly bent metallic sewing
needle was located within the oropharyngeal region slightly to
the right and appeared to lie within the base of the tongue or
epiglottis. The soft palate was swollen as was the retropharyn-
geal region, causing ventral displacement of the nasopharynx.
Treatment/Management: An unsuccessful effort was made
to surgically remove the foreign body. The swelling reduced
and the patient was discharged on a soft diet that he could eat.
The owners were told to return if the dysphagia reoccurred.
Outcome: “Schlutzie” was seen in the clinic two years later
having been just found by the owner bleeding from the ears.
In addition, his left elbow was swollen and painful with a soft
tissue lesion laterally. Radiographs of the elbow joint showed
soft tissue swelling caudal to the proximal ulna without bony
abnormality.
Comments: A history with repeated incidences of this type
strongly suggested that this dog was being abused.
7

Case 7.5
Signalment/History: “Charlie” was a male, Rottweiler
puppy who refused to eat and when he did attempt to drink
water, he experienced difficulty in swallowing.
Physical examination: Marked soft tissue swelling was evi-
dent ventrally from the caudal part of the submandibular re-
gion. An indistinct soft tissue mass could be palpated on the
right side of the neck.
Radiographic procedure: Studies were made of the head
and neck.
Radiographic diagnosis: A thin radiopaque metallic foreign
body (needle) lay lateral to the larynx with a prominent soft
tissue swelling on the right.
Comments: Note the “eye” of the needle was lateral sug-
gesting that it had been pushed into the neck from the right
side. The location of the eye of the needle made it unlikely for
the dog to have been playing with thread and have accidental-
ly swallowed the needle.
7

Case 7.6
Signalment/History: A female Boston Terrier puppy would
not eat. The anorexia had developed acutely.
tion.
made.
Radiographic diagnosis: A linear gastroesophageal foreign
body was identified.
Comments: It is unlikely that this type of foreign body could
accidentally be swallowed by a puppy. This is an example of
animal abuse. (Many thanks to Dr. W.J. Zontine.)
7

Case 7.7
7
At presentation

Signalment/History: “Rover” was a 4-year-old, male Ger-
man Shepherd cross that was presented with a draining tract in
the ventral cervical region, which had been evident for the
previous week. The soft tissue lesion had been explored surgi-
cally several times without a foreign body being located.
Physical examination:The draining tract and associated soft
tissue swelling were obvious.
Radiographic diagnosis (at presentation): The lateral
view showed a foreign body of metallic density just ventral to
the heart (arrows). In addition, fluid was noted between the
sternum and the heart. The cardiac silhouette was elevated.
The dorsal aspect of the thorax appeared normal. Air was pres-
ent in the esophagus just cranial to the hilus.
The pleural fluid was not noted on the DV view because it had
shifted ventrally to the midline. The foreign body lay just to
the right of the midline. The only other abnormal finding was
a malunion fracture of the 6th rib on the left.
Differential diagnosis: The radiographic findings were
those of an intrathoracic foreign body (metal tip of an arrow
with the assumption that a portion of the wooden or plastic
shaft was still attached) and associated fluid that was loculated
within the pleural space ventrally and/or possibly within the
ventral mediastinum. Considering the history, the fluid was
probably septic. Ventral mediastinal adhesions probably caused
the loculation of the fluid ventrally.
Treatment/Management: The foreign body (arrow) was
removed successfully from the thoracic cavity, where it was
located within the ventral mediastinum.
왘왘
7

Radiographic diagnosis (month 3 after presentation):
Final thoracic radiographs were made three months after sur-
gery, when the dog was continuing to have drainage from a le-
sion at the thoracic inlet. On the lateral view, the changes were
limited to the ventral mediastinum, where the residual ventral
mediastinal density was decreased in size but remained persist-
ent. The cardiac silhouette was more normal in position than
before. The lungs were normal in appearance except for a scal-
loping of their edges cranial to the heart suggesting pleural ad-
hesions.
The DV view showed pleural thickening on the right side
caudally that caused a separation of the lung from the chest
wall. Widening of the cranial mediastinum was probably sec-
ondary to the chronic mediastinitis and/or pleuritis. The
healed rib fracture was noted as before.
Comments: The persistent clinical signs were supportive
of an active mediastinitis possibly associated with retention of
a foreign body (probably arrow shaft). It was impossible to
determine from the radiographs the activity of the mediastinal
lesion. Considering the chronicity of the lesion prior to the
surgery, the scarring and adhesions resulting from the wound
and surgery probably healed leaving shadows of this nature.
The clinical signs, however, suggested that this remained a
chronic active mediastinitis.
The etiology was relatively easy to determine in this patient;
however, the status of the mediastinal/pleural fluid could not
be determined. Historically, the mediastinitis/pleuritis was
chronic and probably remained active.
7
Month 3

Case 7.8
Signalment/History: “O.J.” was a 7-week-old, female
Labrador Retriever puppy noticed by the owner to be lame.
Physical examination: Pain was not evident on examina-
tion; however, she was an excited, hyperactive puppy. She was
definitely lame on more than one limb.
Radiographic procedure: A skeletal survey was performed
with comparison films.
Radiographic diagnosis: A greenstick fracture of the mid-
shaft of the right ulna (arrow), complete fractures of the prox-
imal portions of the 2nd
and 3rd
metacarpal bones on the right
(arrows), a transverse fracture of the right tibia, and a fracture
of the right fibula were noted.
Differential diagnosis: In the absence of any explanation of
how the multiple fractures occurred, the possibility of abuse
should be considered.
Treatment/Management: The fractures were treated by
splinting.
Outcome: The radial and ulnar and metacarpal fractures
healed within two weeks. The complete tibial fracture was de-
layed because of movement at the fracture site. “O.J.” was
presented twice again, four months and 6 months later, both
times for lameness. This history is suggestive of continued
abuse.
Comments: Note the two prominent artifacts on the radio-
graphs of the forelimbs. The tape holding the “R” marker ex-
tends across the toes on the right foot, while a large “hair”
makes a curious arc across the 5th
digit on the left foot (arrow).
7

7

Case 7.9
Signalment/History: “Tralee” was a 6-month-old, female
Irish Wolfhound with a firm, hard swelling on the mandible at
the level of the canine teeth. It had been present for two weeks
and was becoming larger.
Physical examination: The mass was easily palpated, was
hard and firm and not painful. The submandibular lymph
nodes were enlarged. The dog permitted an oral examination,
which was unremarkable.
Radiographic procedure: Lateral and oblique studies were
centered on the mass lesion.
Radiographic diagnosis: A 0.8-cm-in-diameter lucent
cavity was present in the ventral cortex at the level of the 2nd
premolar (arrows). A periosteal response created a smooth
border to the lesion. No sequestrum could be identified. The
teeth were normal in appearance and no evidence of fracture
was noted.
Differential diagnosis: A destructive lesion of this type may
have been the result of a primary bone tumor or an infectious
lesion secondary to a foreign body, or a puncture wound such
as would occur due to a bite. The age of the dog and the ab-
sence of any clinical history of a soft tissue lesion excluded
these etiologies. A focal osteomyelitis of this type is often
found in association with an encircling devise such as a rubber
band or string.
Treatment/Management: Surgical excision revealed a
chronic irritative type lesion without evidence of an active os-
teomyelitis.
A surgical biopsy was taken from the tissue and submitted for
examination. The curetted bone contained fibrous connective
tissue and uncalcified bony matrix. It was diagnosed as active
periosteal new bone without evidence of osteomyelitis. The
soft tissue was immature and was heavily infiltrated with neu-
trophils and macrophages. An adjacent lymph node showed a
diffuse increase in fibrous connective tissue. The lesion was
compatible with a chronic irritation due to a foreign body.
Comments: The location and appearance of the lesion was
typical for that seen with a rubber band or string foreign body
placed around the lower jaw.
7

Signalment/History: “Sky”, a 6-year-old, female Aus-
tralian Blue Heeler, was presented with a history of having a
large stick forced into her pharynx with possible entry into the
esophagus.
Physical examination: It was not possible to palpate the cer-
vical region. An open mouth examination was attempted, but
the dog resisted.
Radiographic procedure: Lateral views were made of the
cervical region followed by a barium sulfate swallow.
Radiographic diagnosis (noncontrast study): Free air
was found within the retrolaryngeal space with a thickened
epiglottis and soft palate suggesting a traumatic edema. No ra-
diopaque foreign body was noted. No skeletal abnormalities
were seen.
Case 7.10
7
Noncontrast

Radiographic diagnosis (contrast study): The barium
sulfate swallow was a simple radiographic technique to per-
form and revealed near-normal swallowing function with no
leakage of the contrast agent into the surrounding soft tissues.
However, the soft tissue air remained.
Treatment/Management: The diagnosis was made by the
history furnished by the owner. The exact nature of the pha-
ryngeal or laryngeal injury could not be determined and “Sky”
was released to the owner after two days of hospitalization.
Comments: Patients such as “Sky” should be considered as
having suffered from deliberate abuse.
The cervical region is difficult to evaluate on a DV or VD
view, and oblique views are often of greater value. Increased
size of the retropharyngeal space caused by soft tissue swelling
secondary to trauma is difficult to evaluate because position-
ing of the head influences the size of the space, with its thick-
ness being increased with the head in flexion and decreased
with the head in extension. A lateral view of the head results
in superimposition of the lateral processes of the atlas over the
odontoid process; however obliquity of the head does permits
good visualization of the odontoid process.
7
Contrast

8.1.1 Rodenticide poisoning
Radiographic examination following possible exposure to a
rodenticide can be of value in determining the severity and lo-
cation of the hemorrhage. While coagulation disorders have
many causes, the occurrence of hemorrhage in a previously
healthy patient should suggest inquiry into the possibility of
poisoning. Of course, an acute traumatic event can also result
in severe hemorrhage.
In the case of exposure to a rodenticide, many factors affect
the radiographic appearance of the lesions. The amount of ro-
denticide, the time from poisoning until radiography, and the
influence of therapy all exert a major affect. Still, as can be
seen in the following patients, the location of the hemorrhage
can vary markedly. It is obvious that both thoracic and ab-
dominal centesis play a major role in determining the nature
and volume of the fluid.
왘왘
539
8
Chapter 8
Poisoning

Signalment/History: “Buster” was a 7-month-old, male
Lhasa Apso with primary complaints of inappetence, abdomi-
nal pain, and lethargy. Possible exposure to a rodenticide
could have occurred 24 hours earlier.
Physical examination: His mucous membranes were pale
and he had tachycardia.
Radiographic procedure: Studies of the thorax were made
to establish a database for treatment of the patient. Thoraco-
centesis was also performed.
Radiographic diagnosis: An extensive pleural effusion was
present, but more severe on the right with a mediastinal shift
to the left. The trachea was parallel to the spine indicating
slight elevation of the mediastinal contents. The cardiac sil-
houette could not be evaluated well. The nature of the lung
parenchyma was not clearly visible, but the right lung may
have been atelectic. The diaphragm was caudal and flattened,
though it could not be definitely identified ventrally. A small
pneumothorax on the right was located between the 7th and
8th ribs and was probably secondary to the attempted thoraco-
centesis.
Differential diagnosis: The thoracocentesis revealed a
bloody effusion with a PCV of 16 and total proteins of 5. A
coagulation disorder with hemothorax can be due to a throm-
bocytopenia that is hereditary, acquired, or due to a platelet
dysfunction secondary to rodenticide poisoning. In this pa-
tient, the owners acknowledged likely exposure to Warfarin.
The major bleeding appeared to be pleural; however, medi-
astinal and pulmonary hemorrhage could not be clearly evalu-
ated on this study.
Treatment/Management: Treatment of the poisoning with
Vitamin K, plus treatment of the pneumonia with Baytril and
Amoxicillin enabled “Buster” to be discharged two days fol-
lowing admission.
Subsequent radiographs of this patient suggested clearing of
the pleural fluid with detection of a suspected pneumonia
having developed in the left caudal lung lobe.
Comments: A differential radiographic diagnosis at the time
of the first study might include any form of thoracic mass ex-
pected to produce a pleural effusion. The normal position of
the gastric air bubble tends to rule out a diaphragmatic hernia.
Rodenticide poisoning 541
8

Case 8.2
Signalment/History: “Bridget” was a 2-year-old, female
German Shepherd with a history of coughing associated with
the production of a small amount of blood.
Physical examination: She was febrile with abnormal lung
sounds and it was assumed that she had pneumonia. However,
the PT and PTT were both prolonged, and it was thought that
she could have a clotting problem.
Radiographic procedure (day 1): A marked increase in
fluid density throughout the lung fields was most prominent
on the left side. The prominent air-bronchogram pattern sug-
gested alveolar flooding. Typical for many types of pulmonary
disease, a collapse of the right middle lobe was noted. No pleu-
ral fluid was evident. A mediastinal shift was not evident.
542 Poisoning
8
Day 1

Radiographic procedure (day 16): Clearing of the lung
field was noted with residual peribronchial markings that were
thought to be more prominent than expected at this age.
Treatment/Management: The clinical history suggested
the possibility of a rodenticide poisoning. The extent of the
alveolar fluid seemed to be excessive for pneumonia in a dog
that was not showing severe respiratory signs. The clearing of
the pulmonary fluid was prolonged. The fever, plus the resid-
ual peribronchial markings in a young dog suggest a superim-
posed pneumonia and antibiotic therapy was incorporated in
the treatment. Gram-negative rods were found repeatedly on
tracheal washings taken throughout the time the dog was in
the clinic. The extended hospital stay was due to the delay in
clearing of the pneumonia.
8
Day 16

Case 8.3
Signalment/History: “Thor”, a 1-year-old, male German
Shepherd, was presented with a one-day history of hematuria,
lethargy, anorexia, and coughing.
Physical examination: The lung sounds were harsh, the
dog’s mucous membranes were pale, and he was dehydrated.
Radiographic diagnosis (day 1): Extensive alveolar infil-
trates with prominent air-bronchogram patterns were present
in all lobes except the right caudal and accessory lobes. The
heart remained on the midline. The diaphragm was intact. No
pleural fluid could be seen. A prominent skin fold was noted
on the right. Air in the cranial esophagus created a “tracheal
strip sign”.
544 Poisoning
8
Day 1

Radiographic diagnosis (day 10): The study was consid-
ered to be radiographically normal.
Treatment/Management: The PCV was decreased to
21.1%, RBCs were decreased to 1.93 M/µl, and the platelets
were decreased to 109,000. The diagnosis was a coagulopathy,
probably due to vitamin K antagonism. Complete resolution
of the pulmonary hemorrhage followed treatment with Vita-
min K1 for 30 days.
Comments: Note the abnormal location of the bronchus to
the right cranial lung lobe as it coursed cranially only to make
an abrupt turn. This was noted on both studies and was high-
ly suggestive of an early or partial lung torsion initiated by an
increased weight in a diseased lung lobe in such a deep-chest-
ed dog. The partial torsion could have delayed the clearing of
the pneumonia. “Thor” was discharged and lost to follow-up,
so the clinical importance of this finding could not be deter-
mined.
8
Day 10

Case 8.4
Signalment/History: “Jill” was an 8-year-old, female
Pointer who had been treated with vitamin K for a suspected
Warfarin poisoning. She was referred after the acute phase of
the poisoning because of a suspect cranial thoracic mass.
Radiographic diagnosis (day 10): A ventral cranial tho-
racic density on the midline had a rather distinct margin sug-
gesting a cranial mediastinal mass. The enlarged cardiac sil-
houette suggested a probable pericardial hemorrhage. A loss of
contrast in the abdomen suggested peritoneal fluid.
546 Poisoning
8
Day 10

Radiographic diagnosis (day 40): The mediastinal
mass/fluid had disappeared and there was a decrease in the
width of cardiac silhouette on the VD view.
Treatment/Management: “Jill” had been treated correctly
prior to the time of referral and any pulmonary or pleural
hemorrhage had cleared by that time. The mediastinal fluid
was much slower to resorb and the referring clinician thought
that because of her older age, she had an additional lesion, pos-
sibly a tumor. The mediastinal fluid had cleared by the time of
the second radiographic study disproving that tentative diag-
nosis.
8
Day 40

Case 8.5
548 Poisoning
8
Day 1, referral
Day 3

Signalment/History: “Tasha’ was a 4-year-old, female Ter-
rier mix with a history of induced vomiting following sus-
pected diphacinone intoxication. Clinically, she was improv-
ing at the time of admission to the clinic.
made. Only the lateral views are shown.
Radiographic diagnosis (day 1, referral radiograph):
Pleural fluid and pulmonary fluid were uniformly spread
throughout the lungs and thorax. Mediastinal fluid was evi-
dent cranially, where it caused elevation of the trachea.
Radiographic diagnosis (day 3): Marked clearing of the
pulmonary hemorrhage was evident except cranially, in what
was thought to be a region of mediastinal hemorrhage. Clear-
ing of the pleural fluid was evident.
Radiographic diagnosis (day 6): Radiographs made 3 days
later showed a radiographically normal thorax except for a per-
sistent thickening of the cranial mediastinal shadow.
Comments: “Tasha” was a typical coagulopathy patient ex-
cept for the question of aspiration pneumonia, resulting from
the owner attempting to induce vomition. The radiographs
did not show any changes typical of aspiration pneumonia.
The subsequent clearing of the hemorrhage was more rapid in
the lungs than in the mediastinum. This was to be expected.
8
Day 6

Case 8.6
Signalment/History: “Boobie” was a 4-month-old, male
Brittany with possible exposure to a rodenticide and had been
on treatment for five days when presented for examination.
Physical examination: He was listless, febrile, with occa-
sional lameness, and hematuria.
made.
Radiographic diagnosis (day 5): A bilateral generalized
alveolar pattern was apparent. Widening of the cranial medi-
astinum caused a mass-like lesion.
550 Poisoning
8
Day 5

Radiographic diagnosis (day 8): Partial clearing of the
alveolar effusion was noted as well as a partial resolution of the
cranial mediastinal mass-like lesion.
Comments: The possibility of secondary pneumonia can al-
ways influence the manner of hemorrhage clearing within the
lung as seen on the radiographs in this case.
The clinical response of a patient usually shows improvement
prior to the complete clearance of the pulmonary fluid as seen
on the radiographs in this case. Radiographic examination fol-
lowing possible exposure to a rodenticide can be of value in
the determination of the extent of the hemorrhage. While co-
agulation disorders have many causes, the occurrence of hem-
orrhage in a previously healthy patient should suggest inquiry
into the possibility of poisoning. Of course, an acute traumat-
ic event can also result in severe hemorrhage, but this is less
common.
8
Day 8

8.1.2 Herbicide poisoning
Case 8.7
Signalment/History: “Pooper” was an 8-year-old, female
Labrador Retriever with a history of high fever for 24 hours,
rapid shallow respiration, and abdominal pain. She was re-
ferred for a diagnostic laparotomy. The surgery was delayed
because of an absence of definite clinical signs to support the
requirement for surgery. Two days later, she was in definite
respiratory distress.
thorax.
Radiographic diagnosis (day 1): A minor increase in in-
terstitial lung changes was present. This is not atypical for the
dog’s age; such changes were also suggestive of a pulmonary
effusion. Malunion healing of the 7th
and 8th
ribs on the right
was indicative of an old trauma. In addition, thickened pleura
were adjacent to the malunion rib fractures. The heart was
normal, no pleural fluid was seen and the diaphragm was in-
tact.
552 Poisoning
8
Day 1

Radiographic diagnosis (day 3): A marked increase in flu-
id density in all the lung lobes along with an air-bronchogram
pattern suggested an increase in diffuse alveolar fluid. No pleu-
ral fluid was evident.
Comments: The distribution of diffuse alveolar fluid was not
hilar as would be seen with cardiogenic edema. The distribu-
tion was not lobar as expected with airway-oriented pneumo-
nia and was not characterized by disseminated focal lesions as
expected with hematogenous pneumonia. The acute onset of
clinical signs complicated the determination of the diagnosis.
In this case, paraquat toxicity could only be proven on the ba-
sis of the owner’s information.
Paraquat is a popular and effective herbicide; however, it is a
harsh gastrointestinal irritant and in addition, has a most de-
structive impact on the respiratory tract. Poisoning can occur
with oral, parenteral, aerosol, or dermal exposure. The symp-
toms in man are gastrointestinal pain and vomiting within 24
hours of exposure, followed by respiratory failure. The cause
of the acute interstitial lung disease is unknown. The genera-
tion of toxic oxygen radicals is sufficient to damage normal
pulmonary parenchyma and cause a secondary alveolitis. The
pulmonary lesions can be classified as belonging to the group
of Interstitial Lung Diseases of Unknown Etiology or within
the group of Adult Respiratory Distress Syndrome or Respi-
ratory Distress Syndrome.
Herbicide poisoning 553
8
Day 3

555
Subject index
Numbers in bold type refer to tables
with case references.
A
Abdomen
fluid density mass, 240
Abdominal radiology
indications, 198
radiographic evaluation, 198f.
radiographic features, 199–202
Abdominal trauma, 198
Abdominal tumor, 269
Abdominal wall
hernia, 49, 434
Abscess
sterile, 476
Aerophagia, 111
Air-bronchogram, 17, 35, 544
Airgun pellet, 141
Alveolar fluid, 83
Alveolar infiltrates, 544
Alveolar pattern, 550
Amputation
limb, 364
Apophyseal fracture, see Fracture,
apophyseal
Appendicular skeletal injury
radiographic features, 276
“Apple core” appearance
femoral neck, 356
Arthritis
infectious, 484
inflammatory, 482
septic, 351
suppurative, 484
Arthrogram, 287
Arthropy
muscle, 358, 430, 458
Arthrosis
chronic
elbow, 290
post-traumatic, 307, 309, 341
Aseptic necrosis
post-traumatic, 277
Aspiration
(of) acid material, 145
bronchopneumonia, 154
pneumonia, 151, 153, 184
Atelectasis, see Lung lobe
Atrophic change
pencilling, 442
Avulsion
bone, 376
fracture, see Fracture, avulsion
ischiatic tuberosity, 376, 462
B
Barium enema, 439
Barium sulfate
(used as) contrast agent, 163
inhalation, 164
Bladder, see Urinary bladder
Blastomyces dermatitidis, 471
Bone
atrophy, see Osteoporosis
density, 7
growing
traumatic injuries, 448–469
infection, 431, 470, 473
Bowel disease
obstructive, 214
Bowel loops
air-filled, 46, 51, 95, 101
foreign body, 208
mediastinal shift, 93
obstructing luminal mass, 211
Bronchi
(increase in) fluid density, 70
Bronchiectasis, 163
Bronchopneumonia
aspiration, 154
C
Calcaneous, 382
Calcification
prostate gland, 250
urinary bladder, 250
Calcinosis
tumoral, 488
Callus, 288
Capital epiphysis
slipped, 338, 462
Cardiac silhouette, 92, 108, 112,
116, 136
Cardiomegaly
bilateral, 181
Catheter
retained, 251, 260
Cauda equina syndrome, 522
Collapse
T12, 403
Colon
distended, 423
stricture, 439
Comparison studies, 7
use of, 274f.
Comparison views
use of, 274
Congenital anomaly
German Shepherd, 427
spine, 395
sternum, 45, 391
xiphoid, 101
Contrast
radiographic, 5
Contrast agent, 203
leakage, 245, 267
retention, 237
Contrast studies
traumatized abdomen, 202f.
Contusion
pulmonary, 27, 47, 32, 68, 71,
81
Costochondral junctions, 379
Cystitis
chronic, 260
Cystography, 203
D
Density, 5–7
radiographic, 8
DeVita pin, 342
Diagnostic quality of a muscu-
loskeletal
enhancement, 274f.
Diagnostic radiology, 2
Diagnostic study, 2f.
Diaphragmatic hernia, see Hernia,
diaphragmatic
Diaphragmatic rupture, 14f.
Discospondylitis, 486
Disc space
collapse, 314, 417
L1–2, 417
Displacement
sternebrae, 29
Disruption
rib, 47
Diverticulum, 434
rectal, 433
E
Edema
traumatic, 536
Effusion
pleural, 53, 541
Emphysema
subcutaneous, 13, 23, 27, 32, 49,
120, 130f., 133, 188
Enthesophytes, 292, 309, 491
Epicondyle
malformed, 292
Esophageal disease, 18
Esophageal trauma, 19
Esophagram
positive contrast, 192
Esophagus
dilation, 156, 160, 195
diverticulum, 197
perforation, 181
radiodense foreign body, 181
radiopaque foreign body, 185
rupture, 184
stricture, 158, 161, 190
wall, 187, 189
Excretory urography, 202
F
Feces
impacted, 433
Femoral neck
partial resorption, 465
Femur
malunion fracture, 433
non-union fracture, 445
trauma, 360
Fetus
mummified, 259
Film
density, 5, 8
speed, 8
Film-screen combination, 8
Fistula
perianal, 262
Flail chest, 29, 388
Fluid
peritoneal, 37, 46, 201, 215f.,
219, 230, 238, 240, 246, 257,
323, 495
pleural, 14, 47, 57, 60, 69, 77,
92, 105, 256, 549
Foreign body, 181, 185
arrow shaft, 532
bronchial, 176
linear, 213
metallic, 212, 524, 526, 531
gastroesophageal, 529
linear, 529
radiopaque, 528
needle, 525, 527
radiopaque, 521
small bowel, 213
thorax, 167
trachea, 129, 168, 170
Fracture
apophyseal, 440, 466
avulsion, 285, 380, 383, 447
acute, 469
chronic, 467
bimalleolar, 380
C2, 396
chronic, 311
classification, 276
comminuted, 520
delayed, 440–447
elbow joint, 289
epiphyseal, 425
femoral head, 357
femoral neck, 107, 229, 249, 343
femur, 219, 362, 371
fixation devices, 276f.
forelimb, 298
fragments, 327
“greenstick”, 300
hemipelvis, 321
multiple, 324

humerus, 289
infected, 377
intraarticular oblique, 386
ischium, 331f.
(compression) L3, 410
L4, 109
malleolar, 381
malunion, 299, 304, 418, 425,
430, 433, 435f., 449
chronic, 419
mandible, 394, 515
metacarpal bones, 303f., 316
metatarsal bones, 373
non-union, 303, 319, 440–447
radius and ulna, 442
olecranon, 285
patella, 366
pathologic, 328, 364, 379
multiple, 352
pelvis, 339
multiple, 326
phalangeal, 305
physeal, 356, 440, 449
chronic, 458f.
primarily trabecular bone, 311
pubic, 323
radiocarpal bone, 311
radius, 294–297
radius and ulna, 219
rib, 27, 36, 42, 49, 108
sacroilium, 219
sacrum, 219, 329, 337, 349, 409
Salter Harris, see Salter-Harris
fracture
scapula, 134, 278, 281–283
simple oblique, 297
stress, 301
tibia, 441
transverse, 386
ulna, 294, 296f.
vertebra, 520
Fracture line
epiphysis, 368
shoulder joint, 288
unusual pattern, 331
Fracture-luxation
carpometacarpus, 314
L4, 105
sacrum, 411
T5, 83, 399
T12, 401f.
tibiotarsal joint, 437
G
Gastric distention, 206
Gastric foreign body, 203, 204
radiopaque, 205
German Shepherd
congenital anomaly, 427
Glenoid cavity, 287
incomplete ossification, 287
Grid, 8
technique, 4
Growing bones
traumatic injuries, 448–469
Gunshot injury/wound, 31, 489,
492–522
abdomen, 495
femur, 519
forelimb, 497, 502, 517
head, 499, 501, 516
high-energy bullet, 510, 512
lung, 502
mandible, 515
pelvis, 496
peritoneal fluid, 495
rifle bullet, 509, 513
thorax, 494
tissue damage, 492
Gunshot pellet, 521
H
Hair balls
Head
gunshot injury, 499, 501, 516
trauma 392
Healing
delayed, 440
Heart shadow, 124
Hematoma
lung lobe, 87
pulmonary, 17
Hemipelvis, 423
Hemithorax
fluid dense mass, 77
mass, 196
mass-like lesion, 102
Hemomediastinum, 18, 27, 284,
506
Hemopericardium, 509
Hemoperitoneum, 239
Hemorrhage, 57, 75, 78, 141, 409
fluid, 549
mediastinum, 139
pericardial, 546
pulmonary, 71f., 111, 256
Hemothorax, 36, 541
etiologies, 15
Herbicide poisoning, 552f.
Hernia, 145
abdominal wall, 49, 434
diaphragmatic, 16, 91–107, 363,
433
gastric hiatal, 193, 195
inguinal, 37, 220, 222, 224, 229,
234
paracostal, 47, 51f.
pericardio-diaphragmatic, 107
perineal, 236
Hindfoot, 382
Hip dysplasia, 335, 346, 511
bilateral, 355, 368
Hip joint
radiographic signs of trauma, 340
Hip luxation, 460
Hook, 187
Hyperparathyroidism
secondary, 352
I
Ileus
paralytic, 216
Ilium
malunion fracture, 425, 435
Infection, 501
Inflammation, 471
Injury
chronic, 292
shearing, 293
Intensifying screen, 4
Intercostal muscles
tearing, 24
Intramedullary pin, 420
Intraperitoneal air, 264
Ischiatic tuberosity
avulsion, 376, 462
J
Jejunum
perforated, 217
Joint disease
post-traumatic, 291
Joint effusion, 366
K
Kidney
rupture, 245
Kirschner apparatus, 422
kVp, 8
L
Lesion
granulomatous, 89
post-traumatic, 308
Ligament
collateral, 367
Limb
amputation, 364
disuse, 443
Lucency, 8
Lumbosacral segment, 427
Lung
air-filled cyst, 112
foreign body, 85
Lung field
hyperlucent, 134, 281
Lung lobe, 16, 17, 36, 38, 118,
120, 149
abscessation, 61
accessory, 61
contusion, 29, 65
hematoma, 87
hyperinflation, 69, 87
infiltrative pattern, 31
lucent cyst, 71
mass lesion, 85
obstructive, 153, 176, 184
passive, 27
pneumonic, 85
right middle lobe, 113
“right middle lobe syndrome”,
65f.
soft tissue mass, 87
Lung parenchyma
damage, 15–18
Lung torsion
chronic, 77
Luxation
costovertebral, 51
coxofemoral, 333, 341
bilateral, 333
head, 348
femoral head, 342, 345, 349,
353, 357f., 376
joint, 383
sacroiliac, 337
bilateral, 220
sternum, 390
Lymphosarcoma, 97
M
Malalignment of fragments, 373
Malunion fracture, see Fracture,
malunion
Mandibular symphysis, 393
mAs, 8
Mass
effect, 100f.
epidural, 407
thoracolumbar, 409
intrathoracic, 94, 98, 197
Mediastinal shift, 54, 124, 129
Mediastinum
fluid, 141, 547, 549
hemorrhage, 139
thickness, 141
widening, 550
Metallic fragments, 520
Metallic pellets, 132
“Morgan’s line”, 368
Muscle atrophy, 358, 430, 458
Musculoskeletal injury
use of radiographic examination,
270
Myelomalacia, 415
N
Necrosis
avascular, 459
Needle
foreign body, 525, 527
Non-union fracture, see Fracture,
non-union
O
Opacity, 8
Osteochondritis dissecans, 437
Osteochondroma, 355
Osteomyelitis, 445, 471–486,
501
chronic, 478f., 481, 497
differential diagnoses, 475
multicentric, 477
periapical, 483
Osteopenia, see Osteoporosis
Osteoporosis, 384, 443
disuse, 277, 442f.
556 Subject index

femoral head, 333
Osteosarcoma, 364, 421
P
Palatine bones, 393
Paracostal hernia, see Hernia, para-
costal
Paraquat, 553
toxicity, 553
Pelvis
trauma, 320
Pencilling, 443
atrophic change, 442
Perianal fistula, 262
Peritoneal air, 201
Peritoneal bleeding, 78
Peritoneal fluid, 37, 46, 201, 215f.,
219, 230, 238, 240, 246, 257,
323, 495
Physeal fracture, see Fracture, physeal
Physeal growth injuries, 448
Physeal growth plates, 441
Physeal slippage
Type I, 457
Pleural adhesion, 38
Pleural bleeding, 54
Pleural effusion, 53, 541
Pleural fluid, 14, 15, 47, 57, 60,
69, 77, 92, 105, 256, 549
Pleural scaring, 38
Pleural space, 12
Pleural thickening, 40
Pneumatocele, 17, 54, 79, 155
traumatic, 71
Pneumomediastinum, 18, 32, 43,
130–132, 134, 146, 188, 281
causes, 19
Pneumonia
airway-oriented, 153
aspiration, 151, 153, 184
inhalation, 157
post-traumatic, 18
secondary, 75
Pneumoperitoneum, 226
Pneumothorax, 12–14, 21, 24, 27,
42, 49, 78, 108, 111f., 115f.,
120, 124, 129, 136, 143, 149,
155, 234, 284
causes, 14
tension, 123
types, 13
Poisoning
herbicide, 552f.
rodenticide, 539–551
Prematury growth plate, 455
Pseudoarthrosis, 345, 428, 519
Pulmonary bullae, 17
Pulmonary contusion, 27, 47, 32,
68, 71, 81
Pulmonary fluid, 549
Pulmonary hematoma, 17
Pulmonary hemorrhage, 71f., 111,
256
Pulmonary infiltrate, 80
Pulmonary nodules, 136, 148
R
Radiographic contrast, 5
Radiographic density, 8
Radiographic evaluation, 6
skeleton, 272f.
thoracic studies, 10–12
Radiographic features
appendicular skeletal injury, 276
thoracic trauma, 12–19
Radiographic indications
musculoskeletal trauma, 273
Radiographic (image) quality, 3
factors influencing, 273f.
Radiographic technique, 4
Radiographic viewing, 4f.
Radiological report, 6f.
Radiolucent, 8
Radiopacity, 8
Radiopaque, 8
Radius
growth plate, 455
physeal injury, 457
physeal plate, 453
Rectum
diverticulum, 433
Retrograde urethrography, 203
Retroperitoneal air, 202, 230
Retroperitoneal fluid, 201, 232,
242
Rickets, 379
Rodenticide poisoning, 539–551
S
Sacrum
fracture, 219, 329, 337, 349, 409
Salter-Harris fracture
Type I, 448, 450, 461
Type II, 448
Type III, 448
Type IV, 448, 451, 488
Type V, 448
Type VI, 448
Secondary hyperparathyroidism,
352
Sequential radiographic studies, 275
Sequestration, 481
Sesamoid bone, 285
Shock, 36
Shotgun injury, see Gunshot in-
jury/wound
Skeletal injury
appendicular
Skyline view, 9
Soft tissue
air, 537
mineralization, 490
Spinal cord, see Spine
Spine, 395–417
congenital anomaly, 395
contusion, 415
distorsion, 397
dural tearing, 415
edema, 413
extradural mass, 417
hemorrhage, 413, 415
L6, 33
lumbar, 33
stenosis
congenital, 335
subluxation, 314
T12, 405
T13, 405
Splen
rupture, 239
Spondylosis deformans, 347, 413,
417
Stenosis
spinal canal
congenital, 335
Sternum
congenital anomaly, 45, 391
Stifle joint, 365
stress view, 367
Stomach
air-filled, 93
ingesta-filled, 95
Stress radiograph
tibiotarsal joint, 437
Stress studies, 9
Stress view
stifle joint, 367
tarsus, 383
Subcutaneous air, 88
Supraglenoid tubercle, 279
Surgical sponge, 439
T
Tarsus
stress view, 383
Terms in radiology, 7–9
Thoracic radiographs
positioning, 11
Thoracic wall
disruption, 12
injury, 13, 387
Thoracocentesis, 541
Thorax
foreign body, 167
malformed cavity, 45
Thrombocytopenia, 541
Tibia
avulsion fracture, 447
greenstick fracture, 375
injury to the growth plate, 452
midshaft fracture, 373
open, 376
oblique fracture, 374
spiral fracture, 372
trauma, 369
Tissue density, 5, 9
Toxicity
paraquat, 553
Trachea
elevation, 98
foreign body, 129, 168, 170
perforation, 181
radiopaque foreign body, 165
stenosis, 179
Tracheal wash, 142
Trauma
chronic, 309
old, 313
types, 1
Trochanter
injury, 511
U
Ulna
physeal injury, 457
premature closure, 420
Ureter, 243
rupture, 267
Urethra, 241
penile, 253
rupture, 235, 241, 247, 255
tear, 249
Urethrocystogram
retrograde, 248
Urinary bladder
calcification, 250
rupture, 225, 231f., 235, 323
Urogram
intravenous, 242
retrograde, 221
Uterus
gravid, 425
tear, 264
V
Valgus deformity, 298
W
Wallerian degeneration, 415
Warfarin, 541
Subject index 557

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