Triangle of neck

Presented by:
Dr.Brijesh M. Patel
M.D.S PART I
Oral & Maxillofacial Surgery
KMSDCH
Underguidence of:
Dr.Rakeshsir(PG Guide)
Dr.Navinsir(HOD)
Dr.Deepankarsir

INTRODUCTION:
• Anatomists use the term triangles of the neck to describe the divisions created
by the major muscles in the region.
• The side of the neck presents a somewhat quadrilateral outline, limited,
above, by the lower border of the body of the mandible, and an imaginary line
extending from the angle of the mandible to the mastiod process; below, by
the upper border of the clavicle; in front, by the middle line of the neck;
behind, by the anterior margin of the trapezius.
• This space is subdivided into two large triangles by sternocleidomastoid, which
passes obliquely across the neck, from the sternum and clavicle below, to the
mastiod process and occipital bone above.
• The triangular space in front of this muscle is called the Anterior Triangle Of
The Neck; and that behind it, the Posterior Triangle Of The Neck.

Triangle of neck
Anterior
Submentle
Carotid
Muscular
Submandibular
(digastric)
Posterior
Occipital
Subclavian

BOUNDRIES
Anterior:anterior meian line of
neck extending from
symphysis menti to the
suprasternal notch
Posterior:anterior border of
sternocleiomastoid muscle
Base:lower border of mandible and
imaginary line joining the angle
of mandible to the mastoid
process
Apex: suprasternal notch at the
meeting point betwwen ant.
Border of SCM and ant. Median
line
Roof: investing layer of deep cevical
fascia

• Origin
– medial third of the clavicle
(clavicular head)
– manubrium (sternal head)
• Insertion
– mastoid process
• Nerve supply
– spinal accessory nerve (CNXI)
• Blood supply
– occipital a. or direct from ECA
– superior thyroid a.
– transverse cervical a.
• Actions
Acting alone, tilt the head towards the
ipsilateral shoulder, simultaneously
rotating the head so as to turn the
face towards the opposite side.

• The clavicular fibres are directed mainly to
the mastoid process
• the sternal fibres are more oblique and
superficial, and extend to the occiput.
• The direction of pull of the two heads is
therefore different, and the muscle may be
classed as ‘cruciate’ and slightly ‘spiralized'.
• The two heads are separated near their
attachments by a triangular interval which
corresponds to a surface depression, the
lesser supraclavicular fossa.

Applied Anatomy to SCM
• Branchial cysts
in the upper neck in early adulthood as
fluctuant swellings at the junction of the upper
and middle thirds of the anterior border of
sternocleidomastoid. The cyst typically passes
backwards and upwards through the carotid
bifurcation and ends at the pharyngeal
constrictor muscles, a course which brings it into
intimate association with the hypoglossal,
glossopharyngeal and spinal accessory nerves.
Great care must be taken to avoid damage to
these nerves during surgical removal of a
branchial cyst.

• Branchial fistulae
-connection between the second branchial
pouch and the cervical sinus.
-The fistula typically presents as a small pit
adjacent to the anterior border of the lower
third of sternocleidomastoid, which may weep
saliva and become intermittently infected.
• Branchial cysts, sinuses and fistulae are thought
to arise from inclusions of salivary gland tissue in
lymph nodes: they may also occur around the
parotid gland.

• Origin: Superior nuchal
line, ext. occipital
protuberance, lig. nuchae,
spines of C7 – T12
• Insertion: Lateral 1/3 of
clavicle, acromion, spine
of scapula
• Functions: elevation of
scapula (sup. fibers),
depression of scapula (inf.
fibers), retraction of
scapula (middle fibers),
superior rotation of
glenoid fossa of scapula
(sup. + inferior fibers).

• Nerve innervation:
spinal accessory and ventral rami of C3 and C4
• Vascular supply:
The upper third -by a transverse muscular branch which
arises from the occipital artery at the level of the
mastoid process
The middle portion -by the superficial cervical artery or
by a superficial branch of the transverse cervical artery
The lower third -by a muscular branch from the dorsal
scapular artery

• Anterior triangle of neck subdivide into four
triangle by digastric muscle and superior belly of
omohyoid muscle
1.Submental Triangle
2.Digastric(submandibular Triangle)
3.Carotid Triangle
4.Muscular Triangle(visceral triangle)

Submental Triangle
Boundries:
On each side anterior
belly of digastric muscle
Base:body of hyoid bone
Apex:chin or symphysis
menti
Floor:formed by the
meeting of mylohoid
muscle at the median
raphe extending from
symphysis menti to th
hyoid bone
Roof: investing layer of
deep cevical fascia

CONTENTS OF SUBMENTAL TRIANGLE
1. Submental lymph nodes.
• These receive lymph from the following areas:
• Tip of the tongue.
• Floor of the mouth.
• Mandibular incisor teeth and associated gingivae
• Central part of the lower lip.
• Skin of the chin.
• Lymph from here drains into submandibular and deep
cervical lymph nodes.
2. Submental veins and arteries.
• The submental veins unite to form the anterior jugular
vein

Applied Anatomy Of Submental Triangle
• In infections or cancer from any of the areas of
drainage of the submental nodes, especially the
tip of tongue and lip, the first nodes to be
involved are submental nodes. Subsequently, the
submandibular and deep cervical get involved.
• A discharging sinus on the point of the chin often
results from an abscess of a mandibular incisor
tooth. The pus from the infected tooth passes
from the apex of the submental triangle located
at the inferior end of the symphysis menti where
it forms a sinus from which pus escapes.

• forms a muscular floor for
the oral cavity.
• Origin: It is a flat, triangular
sheet attached to the whole
length of the mylohyoid line
of the mandible .The
mylohyoid line is of variable
ength, sometimes ending
before the lower third
molar (wisdom) tooth.
• Insertion:The posterior
fibres of mylohyoid pass
medially and slightly
downwards to the front of
the body of the hyoid bone
near its lower border.

• The middle and anterior fibres from each side
decussate in a median fibrous raphe that
stretches from the symphysis menti to the hyoid
bone. The median raphe is sometimes absent, in
which case the two muscles form a continuous
sheet, or it may be fused with the anterior belly
of digastric.
• In about one-third of subjects there is a hiatus in
the muscle through which a process of the
sublingual gland protrudes.

Relations
• The inferior (external) surface
platysma
anterior belly of digastric
the superficial part of the submandibular gland
the facial and submental vessels
the mylohyoid vessels and nerve
• The superior (internal) surface
geniohyoid
part of hyoglossus and styloglossus
the hypoglossal and lingual nerves
the submandibular ganglion
the sublingual gland
the deep part of the submandibular gland and its duct
the lingual and sublingual vessels
posteriorly, the mucous membrane of the mouth

Vascular supply
• Arterial supply from the sublingual branch of the
lingual artery, the maxillary artery, via the
mylohyoid branch of the inferior alveolar artery,
and the submental branch of the facial artery.
Nerve Innervation
• Nerve to mylohyoid branch of the inferior
alveolar nerve, which can sometimes also supply
accessory innervation to the posterior
mandibular teeth.

BOUNDRIES
Anteroinferiorly: ant. Belly of
digastric
Posteroinferiorly: post. Belly og
digastric
Base: base of mandible and
imaginary line joining angle of
mandible and mastoid process
Apex: intermediate tendon of
digastric muscle which is bound
down to hyoid bone by fascial
sling
Floor: anteriorly-mylohyoid muscle
posteriorly-hyoglossus and
small part of superior
constrictor

ROOF OF
SUBMANDIBULAR
TRIANGLE:
The skin.
Superficial fascia
Platysma
Deep fascia containing
branches of the facial
and transverse
cutaneous cervical
nerves e.g. cervical
branch of facial nerve

Content
• Its divide into two part by stylomandibular ligament
1.Anterior part
Submandibular gland
Submandibular lymph node
Hypoglossal nerve
Facial vein(suprficial to gland)
Facial artery (deep to land)
Submental artery
Mylohyoid nerve and vessels
2.Posterior part
external carotid artery
carotid sheath and its content
structure passing between external and internal carotid
artery

• Origin
– digastric fossa of the
mandible (at the
symphyseal border)
• Insertion
– hyoid bone via the
intermediate tendon
– mastoid process
• Function
– elevate the hyoid bone
– depress the mandible
(assists lateral pterygoid)

Digastric
• Surgical considerations
Posterior belly is superficial to
ECA
Hypoglossal nerve
ICA
IJV
• Anterior belly
Landmark for identification of mylohyoid for
dissection of the submandibular triangle

Submandibular gland
• superficial part of the gland is situated in the digastric
triangle where it reaches forward to the anterior belly
of digastric and back to the stylomandibular ligament
• Vascular supply:branches of the facial and lingual
arteries
• Lymphatic drainage:deep cervical group of lymph
nodes (particularly the jugulo-omohyoid node),
interrupted by the submandibular nodes.
• Nerve supply:secretomotor supply to the
submandibular gland is derived from the
submandibular ganglion by chorda tympani branch of
facial nerve

Submandibular lymphnode
• Internal to the deep cervical fascia in the
submandibular triangle
• Direct dtrain from external nose, cheek, upper
lip and lateral parts of the lower lip
• Submental,buccal and lingual group of node
drain into submandibular node.

Hypoglossal nerve
• The hypoglossal nerve is motor to all the
muscles of the tongue, except palatoglossus.
• Branches:
1.descending branch
2.meningeal branch
3. Nerves to thyrohyoid and geniohyoid

Applied anatomy
• Complete hypoglossal division causes unilateral
lingual paralysis and eventual hemiatrophy
• the protruded tongue deviates to the paralysed
side and on retraction.
• The larynx may deviate towards the active side in
swallowing, due to unilateral paralysis of the
hyoid depressors associated with loss of the first
cervical spinal nerve which runs with the
hypoglossal nerve

Facial artery
• The facial artery arises anteriorly from the
external carotid in the carotid triangle, above the
lingual artery and immediately above the greater
cornu of the hyoid bone.
• Branches:
1.ascending palatine artery
2.submental artery
3.tonsillarartery
4.glandular branches

Submental Artery
• largest cervical branch of the facial artery.
• Supply:skin and muscle over submental region
• Anastomoses: sublingual branch of the lingual
and mylohyoid branch of the inferior alveolar
artery
over chin: anastomose with the inferior labial
and mental arteries to supply the chin and
lower lip

THE CAROTID SHEATH:
Location:
Longitudinal interval between
cervical viscera (pharynx,
esophagus, larynx, trachea
and thyroid gland) medially,
and prevertebral muscles
posteriorly
Formation:
Prevertebral fascia behind
Pretracheal fascia medially

Mnemonics Of Carotid Sheath Contents
"I SEE(I.C)10 CC's IN THE IV"
I SEE (I.C) = Internal carotid artery
10 = 10 cranial nerve (vagus nerve)
CC = Common carotid artery
IV = Internal juglar vein

CONTENTS OF CAROTID SHEATH
1. Common and Internal Carotid arteries medially.
2. Internal jugular vein laterally.
3. Vagus nerve posteriorly and between the above two.
4. Ansa cervicalis embedded in the carotid sheath(anteriorly).
5. Deep cervical lymph nodes.
Note:
1) Common carotid artery divides at superior border of thyroid gland (C3,4).
2) The carotid sinus (the baroreceptor) is a slight dilatation at the proximal part of the
internal carotid artery. It is innervated by:
•Carotid sinus nerve, a branch of
glossopharyngeal.
•A branch of vagus nerve.
•Sympathetic division of ANS.
3) The carotid body, is a small reddish brown, ovoid mass of tissue located at the
carotid bifurcation. The same nerves that go to the carotid sinus innervate it.

A-Vagus nerve
B-Comon carotid artery

Applied anatomy of submandibular
triangle
• Infection in submandibular region is limited to
a triangular region.
• Posteriorly; hyoid bone and anterolaterally on
each side by halves of mandibular base
• Because the layer of deep fascia is attached to
these bones.
• Triangular swelling= Ludwig’s Angina
• The swelling may push tongue upwards

Carotid Triangle
• BOUNDRIES
Superiorly:posterior belly of
digastric supplemented by
stylohyoid
Anteroinferiorly: superior belly
of omohyoid
Posterior: anterior border of
SCM
Floor:four muscle.
I. Thyrohyoid
II. Hyoglossus
III. Middle constrictor
IV. Inferior constrictor

Floor of the carotid triangle
• The floor is the the deepest aspect
of the carotid triangle.
• The muscles, at this level, are the
middle and lower pharyngeal
constrictors (mpc and ipc).
• The structures seen passing through
this level are:
– superior laryngeal nerve, a branch
of the vagus its 2 terminal branches
– internal laryngeal (ilb--sensory to
upper part of the larynx)
– external laryngeal (elb--motor to
the cricoid muscle)

Roof of the Carotid Triangle
• Skin and superficial
fascia
• Platysma
• Deep fascia;
ramifying in which
are branches of the
facial and cutaneous
cervical nerves.

Omohyoid muscle
• Origin
– upper border of the scapula
• Insertion
– via the intermediate tendon
onto the clavicle and first rib
– hyoid bone lateral to the
sternohyoid muscle
• Blood supply
– Inferior thyroid a.
• Function
– depress the hyoid
– tense the deep cervical fascia

Omohyoid
• Surgical considerations
• Absent in 10% of individuals
• Landmark demarcating level III from IV
• Inferior belly lies superficial to the brachial
plexus
• Phrenic nerve transverse cervical vessels
• Superior belly lies superficial to IJV

Contents carotid triangle
1. Carotid artery:common carotid artery,internal
carotid artery,external carotid artery and its first
five branch
2. Carotid sinus and carotid body
3. Last three cranial nerve:vagus nerve,spinal
accessory nerve,hypoglossal nerve
4. Ansa cervicalis
5. Cervical part of the sympathetic chain
6. Deep cervical lyph nodes

COMMON CAROTID ARTERY
ORIGIN
Right:
Brachio cephalic trunk- behind right sternoclavicular
joint
Left:
Aortic arch – behind manubrium sterni
Course
Extends from sternoclavicular joint to upper border of
thyroid gland c3/ c4
Anterolateral neck in the carotid sheath lateral to
trachea/ esophagus and larynx/ pharynx
Palpable between sternocleidomastoid and angle of
the mandible
Divides in the carotid triangle into internal and external
carotid arteries
Innervation
Parasympathetic: Submandibular ganglion
Sympathetic: superior cervical ganglion

BRANCHES OF EXTERNAL CAROTID ARTERY
From the
ventral side:
From the
dorsal side:
Terminates by dividing
into:
•Superior
thyroid artery.
[5]
•Lingual artery.
[4]
•Facial artery.
[3]
•Ascending
pharyngeal
(may form from
medial side).
•Occipital
artery. [7]
•Posterior
auricular. [6]
•Superficial temporal
artery [1]
•Maxillary artery. [2]

INTERNAL JUGULAR VEIN
Origin
Union of sigmoid and inferior petrosal sinuses
Extent
Base of skull to sternoclavicular joint
Landmark
Between sternal and clavicular heads of sterno cleido mastoid muscles
Tributaries
Pharyngeal veins
Lingual
Common facial
Superior thyroid
Middle thyroid
Termination:
Joins subclavian vein to form brachio-cephalic vein

VAGUS NERVE
COURSE
1. Emerges through jugular foramen
2. Two ganglia- superior and inferior cervical ganglia
3. Runs straight down in the carotid sheath
4. Between and behind carotid artery and internal jugular
veins
5. At the root of the neck, it passes infront of the subclavian
artery to enter mediastinum

BRANCHES AND DISTRIBUTION
Branch Distribution
Meningeal •Dura of posterior cranial fossa
Auricular •Postero inferior quadrant of external surface of tympanic
membrane
•Floor of external auditory meatus
•Skin on the cranial auricular canal
Carotid body branch •Carotid body
•Carotid sinus
Pharyngeal branch •Muscles of pharynx except stylopharyngeus
•Muscles of soft palate except tensor palate
Superior laryngeal •
External Laryngeal •Cricothyroid muscle
•Inferior pharyngeal constrictors
Internal Laryngeal •Pharyngeal mucosa
•Laryngeal mucosa above vocal folds
Recurrent Laryngeal •Trachea and Esophagus
•Cricopharyngeus
•Laryngeal muscles except cricothyroid
•Laryngeal mucosa below vocal folds
•
Cardiac branches •Heart

Carotid body and sinus
•The common carotid artery shows two
specialized organs near its bifurcation, the
carotid sinus and the carotid body.
•They relay information concerning the pressure
and chemical composition of the arterial blood
respectively.
•innervated principally by carotid branch(es) of
the glossopharyngeal nerve, with small
contributions from the cervical sympathetic
trunk and the vagus nerve.

Veins of the Carotid Triangle
• common facial vein (cf) (within
carotid triangle)
• Other structures near by:
– retromandibular vein (rm)
– posterior auricular vein (pav)
– facial vein (fv)
– external jugular vein (ej)
– anterior jugular vein (aj)

Nerves within the Carotid Triangle
• The nerves that enter the
carotid triangle and that lie
superficial to the internal
jugular vein, internal and
external carotid arteries
are:
– hypoglossal (XII)
– C1 root of ansa cervicalis (C1)
– C1 fibers running with
hypoglossal nerve (nerve to
thyrohyoid muscle (nth)
– C2-C3 root of ansa cervicalis
– ansa cervicalis (ac)

Nerves within the Carotid Triangle

Reflection of sternomastoid and removal of
common facial vein
• cca-common carotid
artery
eca-external carotid
artery
• sta-supterior thyroid
artery
• oa-occipital artery
• la-lingual artery
• fa-facial artery
• ica-internal carotid
artery

• Boundries
Anteriorly:anterior median line
extending from hyoid bone to
suprasternal notch
Anterosuperiorly:supe. Belly of
omohyoid
Posteroinferiorly:anterior border of
SCM
Floor: sternohyoid and
sternothyroid muscle
Roof: investing layer of deep
cervical fascia.superficial fascia
contain-anterior jugular vein and
associated lymph node
Apex-jugular notch

CONTENTS OF MUSCULAR TRIANGLE
1) Infrahyoid muscles (strap muscles).
• Sternohyoid 1
• Sternothyroid
• Thyrohyoid
• Omohyoid* 2forming part of the
boundary.
NOTE: These muscles are innervated by
ansa cervicalis (c1-c3) except
thyrohyoid that is innervated by C1
via Hypoglossal nerve. They depress
the hyoid bone and larynx during
swallowing and speaking, anchoring
it in position
2) The anterior jugular veins, run in
both sides of the midline. They are
joined by the jugular arch at the
suprasternal notch.
1-Sternohyoid
2-Omohyoid
3-Sternal head of
sternocleidomastoid

Table of Muscles
Muscle Origin Insertion Action Nerve Supply
Sternohyoid sternum hyoid ansa
Omohyoid
Suprascapular
notch
hyoid ansa
Sternothyroid
Below
sternohyoid on
manubrium
Thyroid
cartilage
oblique line
ansa
Thyrohyoid
Thyroid
cartilage
oblique line
hyoid C1-C2 (ansa)
Anterior Belly
Digastric
-----
intermediate
tendon------
Inner surface of
mandile
Trigeminal
nerve
Posterior Belly
Digastric
Medial aspect
of the mastoid
process
-intermediate
tendon-
Facial nerve
Mylohyoid
Mylohyoid line
of mandible
Hyoid bone
Trigeminal
nerve
Hyoglossus Hyoid bone
Lateral side of
tongue
hypoglossal
Stylohyoid Styloid process hyoid Facial nerve

SUPRAHYOID MUSCLES
MUSCLE ORIGIN INSERTION ACTION INNERVATION
Digastric •Digastric notch,
•medial surface of
base of mastoid
process
•Digastric fossa •Depress the mandible •Posterior belly: facial
nerve
•Anterior belly:nerve
to mylohyoid
Stylohyoid •Back of styloid
process near the base
of skull
•By two slips into the
junction between the
greater horn and body
of hyoid bone
•ELevate hyoid bone •Facial nerve
Mylohyoid •Whole length of
mylohyoid line of its
own side on the inner
aspect of the
mandible from medial
to the third molar
tooth to below the
mental spines
•Anterior ¾: into each
other (interdigitation)
•Posterior ¼: anterior
surface of the body of
hyoid bone
•Forms a mobile but
stable floor of the
mouth
•Mylohyoid nerve
Geniohyoid •Inferior mental spine •Upper border of the
body of hyoid bone.
•Protracts and
elevates the hyoid
bone in swallowing or
if the hyoid is fixed to
depresses the
mandible.
•C1(superior root of
ansa cervicalis)

Posterior Triangle
• BOUNDRIES
Anterior:postrior border of SCM
Posterior:anterior border of
trapezius
Inferior(base):superior aspect of
middle third of clavicle
Apex:meeting point of SCM and
trapezius muscle at superior
nuchal line of occipital bone.its
often truncated.
Roof:investing layer of deep cervical
fascia stretching btween SCM
and trapezius.superficial fascia
contain-platysma,external and
posterior jugularr vein,cutaneous
nerv and vessels

Floor
• Mainly form by 2nd layer of muscle of neck
(above downward)
1. Splenius capitis.
2. Levator scapulae.
3. Occasionally by semispinalis capitis at apex.
4. Scaleneus medius.
5. Scaleneus posterior.
6. Muscular floor is carpeted by preverterbral facia.

splenius capitis (sc)
levator scapulae (ls)
scalenus posterior (sp)
scalenus medius (sm)
scalenus anterior (sa)
inferior belly of omohyoid (io)

• Structure piercing Roof:as follow
lesser occipital nerve,great aurical nerve,transverse
cervical nerve,supraclavicular nerve
Floor:formed from above downward by the
following muscle.
Semispinalis capitis
Splenius capitis
Levator scapulae
Scalenus medius
First digitation of serrtus anterior(sometimes)

Roof
a. Skin
b. Superficial facia
c. Investing layer of deep cervical facia
d. Roof is pierced by :
1. Nerves :
i. Lesser occipital
ii. Great auricle
iii. Transverse cutaneous nerves of neck
iv. Supraclavicular nerves
2. Veins : external jugular veins and its tributaries.
3. Lypmh vessels

1. external jugular vein (blue)
2. superficial cervical lymph nodes (green)
3. lesser occipital nerve (lc)
4. great auricular nerve (ga)
5. transverse cervical nerve (tc)
6. supraclavicular nerves (sc)
7. spinal accessory nerve (sa)

Subdivisions
By inferior belly of
omohyoid muscle
• Larger upper part called
occipital
triangle(omoclvicular)
• Small lower part called
subclavian
triangle(supraclavicular
triangle)
{named by:occipital and
subclavian arteries
respectively contain}

Occipital triangle(omoclavicular
triangle)
• shares the same borders,
except that inferiorly it is
limited by the inferior
belly of omohyoid.
• Floor: from above down,
is formed by splenius
capitis, levator scapulae,
and scaleni medius and
posterior; semispinalis
capitis occasionally
appears at the apex.
• Roof:The triangle is
covered by skin,
superficial and deep
fasciae and inferiorly by
platysma

Content
• Spinal accessory nerve
• 3rd and 4th cervical
nerves providin
branches to levator
scapulae and trapezius
muscles
• Dorsal scapular
nerve(C5)
• Four cutaneous
branchs of cervical
plexus(initial parts)
• Upper trunk of
brachial plexus
• Superficial transverse
cervical artery
• Occipital artery

•spinal accessory nerve
It pierces sternocleidomastoid and crosses levator scapulae
obliquely downwards and backwards to reach the deep surface of
trapezius. The surface marking of its course is in a line from the
junction of the superior one-third and inferior two-thirds of
sternocleidomastoid, to the junction of the inferior one-third and
superior two-thirds of trapezius.
•Cutaneous and muscular branches of the cervical plexus emerge
at the posterior border of sternocleidomastoid.
•Inferiorly, supraclavicular nerves, transverse cervical vessels and
the uppermost part of the brachial plexus cross the triangle.
• Lymph nodes lie along the posterior border of
sternocleidomastoid from the mastoid process to the root of the
neck.

Subclavian Triangle
•The supraclavicular triangle
is the lower and smaller
division of the posterior
triangle, with which it shares
the same boundaries, except
that superiorly it is limited by
omohyoid.
•It corresponds greater
supraclavicular fossa.
•floor :first rib, scalenus
medius and the first slip of
serratus anterior.
•Roof:The triangle is covered
by skin, superficial and deep
fasciae and platysma and
crossed by the supraclavicular
nerves.

Content
Subclavian/supracla
vicular triangle
• 3rd part of subclavian
artery
• Subclavian vein
• Terminal part of external
jugular vein
• Trunks of brachial plexus
• Superficial (transverse )
cervical,suprascapular
and dorsal scapular
arteries
• lymphnodes

• Just above the clavicle, the third part of the subclavian
artery curves inferolaterally from the lateral margin of
scalenus anterior across the first rib to the axilla. The
subclavian vein is behind the clavicle and is not usually
in the triangle; but it may rise as high as the artery and
even accompany it behind scalenus anterior.
• The brachial plexus is partly superior, and partly
posterior to the artery and is always closely related to
it. The trunks of the brachial plexus may easily be
palpated here if the neck is contralaterally flexed and
the examining finger is drawn across the trunks at right
angles to their length. With the musculature relaxed,
pulsation of the subclavian artery may be felt and the
arterial flow can be controlled by retroclavicular
compression against the first rib.

• The suprascapular vessels pass transversely behind the
clavicle, below the transverse cervical artery and vein.
• The external jugular vein descends behind the
posterior border of sternocleidomastoid to end in the
subclavian vein. It receives the transverse cervical and
suprascapular veins, which form a plexus in front of the
third part of the subclavian artery; occasionally it is
joined by a small vein that crosses the clavicle
anteriorly from the cephalic vein. Other structures
within the triangle include the nerve to subclavius,
which crosses the triangle, and lymph nodes

Applied Anatomy of Posterior Triangle
• Nerve point of the neck: is the region around the midpoint of the posterior border of the
sternocleidomastoid muscle. Several nerves lie superficially here, deep to the platysma. This
point is important because:-
– Slash wounds of the neck may severe these relatively superficial nerves , resulting in
loss of cutaneous sensation in the neck, and posterior part of the scalp.
– Anaesthetic agent can be injected here.
• Brachial plexus block . Local anaesthetic solution is injected around the brachial plexus,
superior to the midpoint of the clavicle. Be careful to locate the subclavian artery by
palpation so it is not damaged.
• Subclavian artery, can be pressed in the suprascapular fossa, to control bleeding in the
upper limb.
• Block dessection, is sometimes done in this region for the removal of lymph nodes. The
accessory and Phrenic nerves, together with the other structures should be saved.
• Safe/ danger sides. The accessory nerve may be used to divide the posterior triangle into a
carefree area superiorly and a danger area inferiorly, which has major nerves and blood
vessels

Carefree and carefull zone
Spinal accessory XI runs
posteroinferiorly across the
post. triangle and divides it
into an upper "CAREFREE
ZONE" and a lower
"CAREFUL ZONE". This is
because superior to XI one
can dissect without care
(there are not many
structures in this area) but
inferior to XI great caution
must be exercised
Accessory
N. (XI)

Horner's syndrome
• Results from damage to the cervical
sympathetic chain.
• Therefore it presents with
• Ptosis
• Myosis
• Facial flushing on the affected site

• “The earliest evidence of ancient dentistry -an amazingly detailed dental work on a
mummy from ancient Egypt that archaeologists have dated to 2000 BCE. The work
shows intricate gold work around the teeth. This mummy was found with two donor
teeth that had holes drilled into them. Wires were strung through the holes and
then around the neighboring teeth.” Source: metalonmetal blog.

Triangle of neck

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Triangle of neck