Growth and Development of Cranial Vault
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SKULL ď ľ
At birth-45 bony elements
ď ľ
In adults-22 bones Face-14 bones Cranium- 8 bones
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Bones of the VAULT
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ď ľ SUTURES
-Coronal -Sagittal -Lambdoid -Metopic
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Metopic suture
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Development of calvaria Pre-natal growth Ectomeninx
Endomeninx
Skull bone Dura mater Arachnoid Pia mater
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Ossification centers of the skull
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Fontenellae
-flat bones connected by loose c.t
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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
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Post-natal growth of cranial vault Growth
of brain
Cephalocaudal Theories
gradient of growth
of growth
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Cephalocaudal gradient of growth
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Theories of growth Sutural
theory-by Sicher
Cartilaginous FMH-by
theory-by Scott
Moss
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Genetically determined Growth at sutures Mild effect of local factors
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Intrinsic Genetic factors
Desmocranial Desmocranial Growth Growth
Local epigenetic factors General epigenetic factors Local Environmental factors General Environmental factors
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Importance to cartilage growth Inherent growth potential Sutures respond Primary growth center-nasal septum, synchondrosis & environmental factors www.indiandentalacademy.com
FMH(Moss) Functional matrices Epigenetic control Environmental control
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FMH(Moss)
Intrinsic Genetic factors Local epigenetic factors
Desmocranial Desmocranial Growth Growth
General epigenetic factors Local Environmental factors General Environmental factors
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Post-natal Growth • Brain expands- passively displaced • C.T stroma
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Post-natal Growth • Tension at sutures • New bone dep • ↑ Circumference
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Post-natal Growth • Flattening of bones • Thickening not uniform (sicher)
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Direction of bone growth
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Cranial
growth-combination Sutural
growth
Surface
appo & resorp
Outward
disp by expanding brain
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Anatomy Anterior cranial fossa Middle cranial fossa Posterior cranial fossa
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Anterior cranial fossa Orbital
part of frontal bone
Cribriform Anterior
plate of ethmoid bone
part of body of sphenoid & lesser wing of sphenoid
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Anterior cranial fossa
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Middle cranial fossa
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Middle cranial fossa 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 www.indiandentalacademy.com
Middle cranial fossa Centrally Optic canal Hypophysial fossa
Laterally Superior orbital fissure Foramen rotandum Foramen ovale Foramen spinosum Foramen lacerum www.indiandentalacademy.com
Posterior cranial fossa
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Pre-natal growth Cranium divided into 2 parts •Neurocranium-protects, supports; brain, sense organs •Viscerocranium-elementary, resp track, face, max & mandible
Basicranium - both www.indiandentalacademy.com
Pre-natal growth
Condrification Early evidence of cartilage Late somite period-4th i.u week
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Condrification centers From cartilages-
•Parachordal cartilage •Hypophysial cartilage / postsphenoid •Trabecular cartilage / Presphenoid •Otic capsule •Nasal capsule
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Primordial cartilages
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Pre-natal growth Parachordal cartilage
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Parachordal cartilage Fused sclerotomes arising from occ somites Sclerotomes- bounds magnum Anlagen- basilar, condylar parts www.indiandentalacademy.com
ď ą Hypophyseal cartilage 2 cartilages on either sides - fuse postsphenoid Sella turcea, post part of body of sphenoid www.indiandentalacademy.com
ď ą Trabecular cartilage 2 cartilages on either side Ant part of body of sphenoid
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Trabecular cartilage Laterally Orbitosphenoid cartilage- forms lesser
wing of sphenoid  Alisphenoid cartilage- forms greater wing of sphenoid
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Trabecular cartilage
Anteriorly presphenoid fuse
Mesethmoid cartilage
At birth – Ethmoid bone www.indiandentalacademy.com
ď ą Otic capsule Otic capsule
Mastoid & Petrous part of temp bone
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ď ą Nasal capsule Conrify in 2nd i.u month
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Chondrocranial ossification
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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 www.indiandentalacademy.com
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 www.indiandentalacademy.com
Occipital bone ď ľ
Single median endochondral ossi center at 11th week ant to fora magnum& ant 3rd occi condyl
ď ľ
pair of endochondral ossi centers at 12th week from exocci bone lat to magnum including 2/3rd occi condyl www.indiandentalacademy.com
Temporal bone
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Temporal bone 21 ossi centers squamous & tympanic comp – ossify i.m Petrosal & styloid elements - endochond
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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 www.indiandentalacademy.com
Ethmoid bone
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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
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Inferior nasal concha Purely
endochondral bone
Single center
Cartilage
of lat part of nasal capsule
appear in 5th i.u mth
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Sphenoid bone
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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 www.indiandentalacademy.com
Cranial base angulation
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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.
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Post-Natal growth Endocranial surface – resorptive
Ă— Multidirectional enlargement
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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 www.indiandentalacademy.com
Post-natal growth Fossa expands outward by resorption, Partitions between them enlarge inward by deposition
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Post-natal growth ďƒ˜ Remodelling provides stability for nerves & vessel passage way ďƒ˜ Foramina undergo remodelling & drift to maintain position of cranial nerves & major blood vessels
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Synchondrosis  Regarded as growth center & pacemaker of cranial base  Midline part of cranial base
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Synchondrosis at the base Spheno-ethmoidal synchondrosis Intersphenoidal synchondrosis Spheno-occipital synchondrosis Intraoccipital synchondrosis www.indiandentalacademy.com
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
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Structure of synchondrosis Zones of cartilage Familial reserve zone Cell division zone Hyper tropic zone Calcified zone
Two major directions Of linear growth www.indiandentalacademy.com
Structure of synchondrosis
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 Cranial base growth at s-o syn is reltd to primary displacement  Sinus is drawn out
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Expansion of middle cranial fossa
Secondarily displaces – Ant cranial fossa , naso -max complex & the mandible
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Frontal lobe & ant cranial fossa growth complete by 5 – 6 yrs Temporal lobe& middle fossa continue to grow for several yrs
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Post-natal growth
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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
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