Growth &development of cranial vault & base /fixed orthodontic courses

GROWTH & DEVELOPMENT OF
CRANIAL VAULT & BASE

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INDIAN DENTAL ACADEMY
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Skull



At Birth- 45 bony
elements

 In Adult- 22 bones
Face- 14 bones
Cranium- 8 bones

Cranium




Paired:- 1. parietal
2. temporal
Unpaired
1. frontal
2. occipital
3. sphenoid
4. ethmoid


Four regions of the Craniofacial complex

 The Cranial Vault
 The Cranial Base
 The Naso-maxillary complex
 The Mandible


Further –
Pre - natal and Post - natal growth
Attention to:1. Site and location of growth
2. Type of growth occurring.
3. Determinant or controlling factors.


Anatomy


Norma Verticalis – Above



Norma Basalis – Below



Norma Lateralis – Side



Norma Occipitalis – Back



Norma Frontalis - Front


 Span –
 Superciliary ridges & glabella of frontal
bone
upto & including Squamous occipital bone.
Also includes part of Squamous temporal
bone laterally.






When viewed from above:a Ellipsoidal (roughly)
b Bones –
 Frontal
 Parietal
 Occipital
 Temporal
 Greater wing of sphenoid

c. Sutures
 Frontal (metopic)
 Coronal
 Sagittal
 Lambdoid
 Bregma
 Lambda


Neurocranium


Vault of skull(calvaria)



Phylogenetically-recent origin, to cover the
newly expanded brain.



Formation- intramembranous bone of paraxial
mesodermal & neural crest origin



Known a desmocranium.




Cranial base



Derived phylogenetically –ancient cranial floor.



Associated with the capsular investments of
nasal & auditory sense organs.



Neural crest origin.



Cartilaginous precursor-chondrocranium.


Development of calvaria
Pre-natal growth
Endomenix
Ectomeninx

Arachnoid
Piamater
Skull bone
Duramater


Ossification centers of the skull
Mesoderm –
Frontal, Parietal, sphenoid, petrous temporal &
occipital.
Neural crest –
Lacrimal, nasal, squamous temporal,
zygomatic, maxilla & mandible


Ossification centers of the skull


Pre-Natal Growth


Frontal Bone


Primary centre ------ Superciliary arch(8 th
wk)



Secondary centers ------ zygomatic process,
(fusion 6-7 mts)

nasal spine,
trochlear fossae

At birth- Metopic suture, fusion 2-7yrs

Pre-Natal Growth


Parietal bone




Occipital bone (Squamous part) 8th wk




Region of Parietal eminence 8th wk, fuse by 4th
month.
Just above superior nuchal line

Temporal bone (Squamous part)


Root of zygoma

Frontanellae




Flat bones connected by loose connective
tissue.
Close at various times- 3 months to 2 years.


Fontenallae

Time of closure

-Anterior

-2nd year

-posterior

-2 mts

-Ant lateral

-3mts

-Post lateral

-2nd year

Pre-Natal Growth
-Control


Intrinsic genetic factors



Epigenetic factors



Environmental factors


Intrinsic Genetic control
Local epigenetic factors

Cranial
Cranial
differentiation
differentiation

General epigenetic factors
Local Environmental factors
General Environmental factors


Pre-Natal Growth
-Control
Shift of belief:Genetic influence

Epigenetics

Examples- Primordia of eye.
- Brain.

Post-Natal Growth
Various Theories of Growth, and how they relate
to the cranial vault.
Sicher’s Sutural dominance theory
Scott’s Cartilaginous theory
Moss’ FMH


Sutural Theory

 Genetically

determined

 Growth at sutures
 Mild effect of local factors ex- remodeling
under the influence of muscles.


Sichers Theory

Desmocranial
Desmocranial
Growth
Growth



Cartilagenous theory







Intrinsic growth controlling factors –
cartilage,periosteum.
Sutures-secondary, dependent on extra skeletal
influence.
Cartilage-primary centers of growth.
Nasal septum-major contributor in maxillary
growth.

Post-Natal Growth

Chondrocranial
Chondrocranial
Growth
Growth


Desmo- Sutures
cranial
Periosteal
Growth growth


Post-Natal Growth
Moss’ FMH


Desmocranial
Desmocranial
Growth
Growth


Post-Natal Growth
Moss’ explanation for brain growth controlling
growth of the cranium…
Hydrocephalus, synostosis


Van Limborgh's Summarization:1.

Intrinsic control of growth at
synchondroses

2.

Intrinsic control of sutural growth is less

3.

Synchondroses

4.

Sutural growth controlled in part by
growth of cranial base

Growth centre


5. Periosteal bone growth (vault) controlled
epigenetically by adjacent structures
6. Growth of cranial vault also controlled by
local environmental factors (muscle forces
inclusive)


Post-Natal Growth
Growth of the cranial vault –
direct influence of Neurocranial capsule







As brain expands seperate bones of calvariadisplaced outwardly.
Passive movement.
Each separate bone is enmeshed within
connective tissue stroma.




Primary displacement- tension in sutural
membranes.



Response-new bone deposition-sutural edges.



Each separate bone enlarges-circumference.



Endosteal surfaces-resorptive, overall
thickness &expands medullary spaces.


Post-Natal Growth
Thickening not uniform:Inner table
Brain
Outer table

mechanical influences
and functional stresses

Growth of the frontal sinus (Benninghoff)


Post-Natal Growth
90% of cranial vault growth complete by 5-6 yrs
In accordance with
-Scammon’s curve
- Cephalocaudal Gradient.


Clinical implications








Altered time closure of sutures-variable
distortions of skull shape.
Delayed midline ossification of frontal & sagital
sutures –anterior frontanelle may remaine open.
Cretinism,progeria,trisomy 21,cleidocranial
dysostosis.
Premature synostosis – Apert syndrome &
crouzen syndrome.







Conditions like hydrocephaly, microcephaly.
Abnormal external forces during developmentdistort cranial morphology-bizzare shapes of
skulls .
Defect in closure of foramen caecum at the
ethmoid-frontal suture herniation of cranial
content into the facefrontal encephaloceles.



1.
2.
3.

Cranial growth is a combination of
Sutural growth
Surface deposition & resorption
Centrifugal displacement by the expanding
brain.


GROWTH & DEVELOPMENT OF
CRANIAL BASE


Cranial Base




Reasonably stable reference structure in
cephalometric analysis
Basis to compare and understand abnormal
growth patterns


Functions


Supports & protects the brain & spinal cord



Articulation of skull with vertebral column ,
mandible & maxilla



Buffer zone between the brain, face &
pharyngeal region

Anatomy


Anterior cranial fossa



Middle cranial fossa



Posterior cranial fossa


Anterior cranial fossa
1.
2.
3.

Orbital part of frontal bone
Cribriform plate of ethmoid
Anterior part of the body of sphenoid &
lesser wing


It is deeper than the anterior fossa


It shaped like a butterfly. In front it is bounded
by
posterior borders of the lesser wing of sphenoid
and the body of the sphenoid,



Behind by superior borders of the temporal
bones & Dorsum sellae of sphenoid bone

Centrally
 Optic Canal
 Hypophyseal Fossa
Laterally
 Superior Orbital
Fissure
 Foramen Rotundum
 Foramen Ovale
 Foramen Spinosum
 Foramen Lacerum



Largest and deepest of the cranial fossa.



Sorrounded by dorsum cella, posterior part of
body of sphenoid bone & basilar part of
occipital bone- anterior.



Posterior- lower portion of squamous part of
occipital bone.


Various foramina
 Foramen magnum
 Jugular foramen
 Internal acoustic meatus
 Facial canal
 Hypoglossal canal


Pre-natal growth
Cranium

 Neurocranium-protects, supports;brain, sense
organs

Viscerocranium-alimentary, respiratory tracts,
face, maxilla & mandible

Basicranium - both

Prenatal growth
Chodrification


Mesenchyme derived from paraxial mesoderm
and neural crest .



Form ectomeningeal capsule.




Earliest evidence of skull formation.
Mesenchyme starts converting into Cartilage
Starting on day 40 i.u. Cartilage

cartilages


parachordal cartilage



Hypophyseal cartilage



Otic capsule.



Nasal capsule


Parachordal cartilage


Chondrification centers forming around the
cranial end of the notochord



Parachordal cartilages fuse with the
sclerotomes arising from occipital somites
surrounding the neural tube


Parachordal cartilage


Hypophyseal cartilage
2 Hypophyseal cartilages - Post sphenoid
Sella turcica
Body of the sphenoid (post.
Part)


2 Pre sphenoid cartilage- Pre sphenoid bone
Body of the sphenoid bone
(ant. Part)


Most anteriorly- presphenoid cartilagesMesethmoid
Ossifies into perpendicular plate of ethmoid
Upper edge forms crista galli





Orbito sphenoid  Lesser wing
Alisphenoid
 Greater wing


Otic capsule
Mastoid and petrous portions of the temporal
bones
Otic capsule does not chondrify.


Nasal capsule- 2nd month i.u
Cartilages of nostrils and the nasal septal cartilage


Functional matrix- downward & forward growth



Transfer’s compressive forces from incisor region
to the sphenoid region


Primordial cartilage


Chondrocranial ossification
110 ossification centers –embryonic human
skull.
 Ossification starts in the 4 months.
Unossified chondrocranial remnents: Alae & septum of the nose
 Spheno-occipital & spheno-petrous junctions.
 Apex of the petrous bone
 Between the separate parts of occipital bone.



Chondrocranial ossification


Occipital bone


7 ossification centers - 2 intramembranous 5
endochondral



Sq portion above sup nuchal line –ossify
from pair of i.m ossi centers 8th i.u week



Infranuchally – pair of endochondral
centers 10th i.u week



Single median endochondral ossi center at 11 th
week
ant to foramen magnum & ant 3rd occipital
condyle.



pair of endochondral ossification centers at 12 th
week from exoccipital bone lateral to magnum
including 2/3rd occi condyle.


Temporal bone

 21 ossi centers
 squamous & tympanic portion – ossify i.m
 Petrosal & styloid elements - endochondrally




Sq portion – single center at 8th i.u week.



Tympanic ring- 4 centers at 3rd i.u month.



Petrosal part- 14 centers; appear at 16 th week,
fuse 6th i.u month



Styloid process- 2 centers upper center- just
before birth
lower center- just after birth


Ethmoid bone – 3 centres
 A single median center -Perpendicular plate
& crista galli


Lateral labyrinths in the nasal
cartilages- 2 endochondral centers


Ossification-sphenoid bone
Intramembranous ossification centres
 Medial pterygoid plates – 2


Lateral pterygoid plates -2

Endochondral ossification centres
 Presphenoid
– 3
 Postsphenoid –
4
 Orbitosphenoids - 2
 Alisphenoids
- 2
 Pterygoid hamuli - 2

Ossification
Bone

Site & number of ossification
Intramembranous

Occipital -

supra nuchal
squamous (2)

Temporal -

Endochondral

squamous (1)
tympanic (4)

Ethmoid -

-

infra nuchal squamous(2)
Basilar (1)
Exoccipital (2)
petrosal (14)
styloid (2)
lateral labarynths (2)
perpendicular plate;
crista (1)


Bone

Site & number of ossification
Intramembranous

Vomer Sphenoid -

Endochondral

Alae (2)
Medial pterygoid pre sphenoid (3)
plates (2)

post sphenoid (4)

Lateral pterygoid orbitosphenoid (2)
plates (2)
elisphenoids (2)
pterygoid hamulus (2)
sphenoidal conchae( 2)

Inferior nasal conchae www.indiandentalacademy.com

lamina (1)

Cranial base angulation
Angle at the hypophyseal fossa where prechordal
& chordal parts meet each other




Highly Uneven



Anterior cranial base increases its length
and width by 7 folds between the 10th and
40thweek of I.U life



Posterior cranial base grows only 5 fold


Post natal growth
Expansion of cranial base occurs by




Growth of the cartilage remnants of the
chondrocranium- basicranial bones
Forces from growing brain




Cranial base acts as a template from which the
face develops



The endocranial surface of the basicranium is
resorptive in most areas



Remodeling is required to accommodate the
massively enlarged human brain


Fossa enlargement


 Bony elevations b/w fossae, divide fossa
into various compartments

 Middle & post fossae by petrous
elevation
 Olfactory fossae by crista galli
 Rt & left mid cranial fossae by midline
sphenoidal elevation
 Rt & left ant & post cranial fossae by
longi midline bony ridge




Fossa expands outward by resorption,
Partitions between them enlarge inward by
deposition


synchondrosis






Bands of cartilage remain at the junction of
various bones.
Regarded as growth center & pacemaker of
cranial base.
Present in midline part of basicranium


 Synchondrosis at the base

 Spheno-occipital synchondrosis
 Inter-sphenoidal synchondrosis
 Spheno-ethmoidal synchondrosis
 Intra-occipital synchondrosis

Synchondrosis of cranial base


Spheno-occipital synchondrosis






Major contributor in the post natal growth.
Fuses at 12 to 13 years in girls & 14 to 15 years
in boys.
Ossifies at 20 years of age.
Pressure adapted bone growth mechanism.


Structure of synchondrosis
Zones of cartilage Familiar reserve zone
 Cell division zone
 Hypertropic zone
 Calcified zone






Endochondral bone growth – primary
displacement of bones involved.
Sphenoid & occipital bones moved apartprimary displacement processes

Two major directions
of linear growth


Hunter-Enlow growth equivalents concept




Frontal lobe growth
completes by 5years.



Temporal lobes
continue to enlarge
for several more
years and displaces
the frontal lobe
forward.

Clinical implications
Configuration of neurocranium(& brain)
determines a person’s head form type
- Dolicocephalic
- Brachycephalic
- Mesocephalic


Cranial base growth for Dutch boys and girls –
Monique Henneberke &
Birte Prahl Andersen (AJO 1994 )
Hypothesis that there is no difference in the
cranial base growth between children with or



without ortho treatment- was tested
S-N 153(boys)and 167 (girls)
N-Ba and S-Ba 116 (boys) and 116 (girls), 714 yrs
Mixed longitudinal study

Results
1.

The effect of orthodontic therapy on cranial
base was not significant

2.

The cranial base displayed sexual
dimorphism in absolute size, timing and
amount of growth.

3.

Girls did not show growth spurts where as
boys showed growth spurts for S-N and NBa.

Achondroplasia


Deficient growth at synchondrosis.



Disturbance in endochondral bone formation



Maxilla is not translated forward



This results in abnormal depression of the
bridge of the nose



Relative midface deficiency






Premature ossification or synostosis of the
suture between the presphaenoid and
postsphenoid parts of the spheno-occipital
suture
depressed nasal bridge and dished face




Anomalous development of the presphenoidal
elements
Excessive separation of orbits and abnormally
broad nasal bridge  Hypertelorism



Anecephaly (Absence of calvaria )
Retain acute cranial base flexure




Cliedocranial disostosis

Abnormalities of the skull, teeth, jaws and
shoulder girdle


Afflictions of cartilage growth cranial base
with angulation-achondroplasia ,critinism,
down’s syndrome


REFERENCES
1. Craniofacial Embryology
G.H.SPERBER
2. Essencials Of Facial Growth
D.H.ENLOW
3. Contemporary orthodontics
W.R.PROFFIT
4. Orthodontics principles and practice
T.M. GRABER
5. Anatomy –Gray

6. Cranial Base Growth For Dutch Boys & Girls
– M.Herneberke,b.P. Andersen
(AjoNovember; 1994 )

7. Grants Atlas


Thank you
Leader in continuing dental education


Growth &development of cranial vault & base /fixed orthodontic courses

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