Growth and Development of the Cranial Vault (38

Growth and Development
of Cranial Vault

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SKULL


At birth-45 bony
elements



In adults-22 bones
Face-14 bones
Cranium- 8 bones


Bones of
the
VAULT


 SUTURES

-Coronal
-Sagittal
-Lambdoid
-Metopic


Metopic suture


Development of calvaria
Pre-natal growth
Ectomeninx

Endomeninx

Skull bone
Dura mater
Arachnoid
Pia mater


Ossification centers of the skull


Fontenellae

-flat bones connected by
loose c.t


Time of closure

Fontenallae
-Anterior

-2nd year

-posterior

-2 mts

-Ant lateral

-3mts

-Post lateral

-end of 1 yr

-Medial frontal suture

-6 to 8 yrs


Post-natal growth of cranial
vault
 Growth

of brain

 Cephalocaudal
 Theories

gradient of growth

of growth


Cephalocaudal gradient of growth


Theories of growth
 Sutural

theory-by Sicher

 Cartilaginous
 FMH-by

theory-by Scott

Moss


Genetically determined
Growth at sutures
Mild effect of local factors


Intrinsic Genetic factors

Desmocranial
Desmocranial
Growth
Growth

Local epigenetic factors
General epigenetic factors
Local Environmental factors
General Environmental factors


Importance to cartilage growth
Inherent growth potential
Sutures respond
Primary growth center-nasal septum,
synchondrosis
& environmental factors

FMH(Moss)
Functional matrices
Epigenetic control
Environmental control


FMH(Moss)

Intrinsic Genetic factors
Local epigenetic factors

Desmocranial
Desmocranial
Growth
Growth

General epigenetic factors
Local Environmental factors
General Environmental factors


Post-natal Growth
• Brain expands- passively displaced
• C.T stroma


Post-natal Growth
• Tension at sutures
• New bone dep
• ↑ Circumference


Post-natal Growth
• Flattening of bones
• Thickening not uniform (sicher)


Direction of bone growth


 Cranial

growth-combination
 Sutural

growth

 Surface

appo & resorp

 Outward

disp by expanding brain


Anatomy
Anterior cranial fossa
Middle cranial fossa
Posterior cranial fossa


 Orbital

part of frontal bone

 Cribriform
 Anterior

plate of ethmoid bone

part of body of sphenoid &
lesser wing of sphenoid


Deeper than ant cranial fossa
 Shaped like a butterfly
 In

front bounded by post part of
lesser wing of sphenoid & body of
sphenoid

 Behind

by sup border of temporal
bones & dorsum sellae of sphenoid
bone

Centrally
Optic canal
Hypophysial fossa

Laterally
Superior orbital fissure
Foramen rotandum
Foramen ovale
Foramen spinosum
Foramen lacerum

Posterior cranial fossa


Pre-natal growth
Cranium divided into 2 parts
•Neurocranium-protects, supports;
brain, sense organs
•Viscerocranium-elementary, resp
track, face, max & mandible

Basicranium - both

Pre-natal growth

Condrification Early evidence of cartilage
Late somite period-4th i.u week


Condrification centers
From cartilages-

•Parachordal cartilage
•Hypophysial cartilage / postsphenoid
•Trabecular cartilage / Presphenoid
•Otic capsule
•Nasal capsule

Primordial cartilages


Pre-natal growth
Parachordal
cartilage


Parachordal cartilage
Fused sclerotomes
arising from occ somites
Sclerotomes- bounds
magnum
Anlagen- basilar, condylar parts

 Hypophyseal cartilage
2 cartilages on either sides - fuse
postsphenoid
Sella turcea,
post part of body of
sphenoid

 Trabecular cartilage
2 cartilages on either side
Ant part of body of sphenoid


Trabecular cartilage
Laterally Orbitosphenoid cartilage- forms lesser

wing of sphenoid
 Alisphenoid cartilage- forms greater
wing of sphenoid


Trabecular cartilage

Anteriorly presphenoid fuse

Mesethmoid cartilage

At birth – Ethmoid bone

 Otic capsule
Otic capsule

Mastoid & Petrous part of temp bone


 Nasal capsule
Conrify in 2nd i.u month


Chondrocranial ossification


Chondrocranial ossification
• 110 ossi centers – embryonic skull
• 45 bones – neonatal skull
• 22 bones – young adult
• Unossified remnents – ala,nasal sepum,
speno-occi&speno-petrous jn,apex
of petrous bone,btwn separate
parts of occ bone

Occipital bone


7 ossi 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

Occipital bone


Single median
endochondral ossi
center at 11th week
ant to fora magnum&
ant 3rd occi condyl



pair of endochondral
ossi centers at 12th
week from
exocci bone lat to
magnum including
2/3rd occi condyl

Temporal bone


Temporal bone
21 ossi centers
squamous & tympanic comp – ossify i.m
Petrosal & styloid elements - endochond


Temporal bone








Sq portion – single center at 8th i.u
week
Tympanic ring- 4 centers at 3rd i.u
month
Petrosal part- 14 centers; appear at
16th week, fuse 6th i.u month
Styloid process- 2 centers
upper center- just before birth
lower center- just after birth

Ethmoid bone


Ethmoid bone


Ossifies from 3 centers



Single median center in mesethmoid
cartilage – forms ppd plate & crista
galli just before birth
A pair appear in nasal capsular carti
4th i.u month




Inferior nasal concha
Purely



endochondral bone

Single center

 Cartilage

of lat part of nasal capsule

appear in 5th i.u mth


Sphenoid bone


Sphenoid bone
•Intramembranous ossification centers
Medial pterygoid plates – 2
Lateral pterygoid plates -2
•Endochondral ossification centers
Presphenoid – 3
Postsphenoid – 4
Orbitosphenoids - 2
Alisphenoids
- 2
Pterygoid hamuli - 2

Cranial base angulation


Cranial base angulation
Hypophyseal fossa (prechordal & chordal
parts)
Nasion - Sella - Basion .
Precartilage stage – 150°,
highly obtuse
Cartilage stage
130°
Preossification stage – 115°-120°,more acute
Ossification stage – 125°-130 , postnatally.


Post-Natal growth
Endocranial surface – resorptive

× Multidirectional 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

Post-natal growth
Fossa expands outward by resorption,
Partitions between them enlarge
inward by deposition


Post-natal growth
 Remodelling provides stability for
nerves & vessel passage way
 Foramina undergo remodelling &
drift to maintain position of cranial
nerves & major blood vessels


Synchondrosis
 Regarded as growth center &
pacemaker of cranial base
 Midline part of cranial base


 Synchondrosis at the base
 Spheno-ethmoidal synchondrosis
 Intersphenoidal synchondrosis
 Spheno-occipital synchondrosis
 Intraoccipital synchondrosis

Spheno-occipital synchondrosis
 Principle growth cartilage of base
 Present till brain & base conti to
grow & expand
 Its growth ceases at 12 to 15, at
20 sphenoid&occi segments fuse


Structure of synchondrosis
Zones of cartilage Familial reserve zone
 Cell division zone
 Hyper tropic zone
 Calcified zone

Two major directions
Of linear growth

Structure of synchondrosis


 Cranial base growth
at s-o syn is reltd to
primary displacement
 Sinus is drawn out


Expansion of middle cranial fossa

Secondarily displaces – Ant cranial
fossa , naso -max complex & the
mandible


Frontal lobe & ant cranial
fossa growth complete by
5 – 6 yrs
 Temporal lobe& middle
fossa continue to grow
for several yrs


Post-natal growth


References

Craniofacial Embryology
-G.H.SPERBER
 Essentials Of Facial Growth
-D.H.ENLOW
 Orthodontics- principle & practice
-T. M. GRABER
 Anatomy –Gray
 Contemporary orthodontics
W.R.PROFFIT



THANK
YOU


Growth and Development of the Cranial Vault (38

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