GROW TH AND DEVELOPMENT OF CRANIAL VAULT
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In the closest of union there is still some separate existence of component parts; in the most complete separation there is still a reminiscence of union. The notebook of Samuel Butler
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SKULL At Birth- 45 bony elements ď ° In Adult- 22 bones Face- 14 bones Cranium- 8 bones ď °
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Four regions of the Craniofacial complex:o
The Cranial Vault
o
The Cranial Base
o
The Naso-maxillary complex
o
The Mandible
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Further – Pre - natal and Post - natal growth Attention to:i. Site and location of growth ii. Type of growth occurring. iii. Determinant or controlling factors.
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ANATOMY
Norma Verticalis – Above
Norma Basalis – Below
Norma Lateralis – Side
Norma Occipitalis – Back
Norma Frontalis - Front
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anatomy
Span – Superciliary ridges & glabella of frontal bone upto & including Squamous occipital bone. Also includes part of Squamous temporal bone laterally.
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anatomy When viewed from above:a. Ellipsoidal (roughly) b. Bones – Frontal Parietal Occipital Temporal Greater wing of sphenoid www.indiandentalacademy.com
anatomy c.
Sutures Frontal (metopic) Coronal Sagittal Lambdoid Parietal with Sphenoid Parietal with Temporal Bregma Lambda www.indiandentalacademy.com
scalp
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Pre-Natal Growth Mesenchyme first arranged as capsular membrane Endomeninx – Neural crest origin Ectomeninx – Neural crest and paraxial mesoderm.
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Pre-Natal Growth Ectomeninx
Duramater
Superficial membrane
Vault www.indiandentalacademy.com
Base
Pre-Natal Growth Endomeninx
Piamater
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Arachanoid
Pre-Natal Growth
Close relation between ectomeninx and endomeninx except in areas of venous sinuses.
Dura mater- Fiber bundles- Falx cerebri, Falx cerebelli and Tentorium cerebelli- closely related &strongly attached to the sutural system- later develops in the vault .
Shape of brain www.indiandentalacademy.com
Pre-Natal Growth Site Ossification Controlling factor
site of future bones Intra membranous Brain growth
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Pre-Natal Growth Mesoderm – Frontal, Parietal, sphenoid, petrous temporal & occipital. Neural crest – Lacrimal, nasal, squamous temporal, zygomatic, maxilla & mandible
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Pre-Natal Growth
Frontal Bone
Primary centre ------ Superciliary arch(8th wk)
Secondary centers ------ zygomatic process, (fusion 6-7 mts)
nasal spine, trochlear fossae
At birth- Metopic suture, fusion 2-7yrs www.indiandentalacademy.com
Pre-Natal Growth
Parietal bone
Occipital bone (Squamous part)
Region of Parietal eminence 8th wk, fuse by 4th month. Just above superior nuchal line
Temporal bone (Squamous part)
Root of zygoma www.indiandentalacademy.com
Pre-Natal Growth
Tympanic ring of temporal bone
4 centers in lateral wall of tympanum appear in the 3rd month of i.u birth, fuse at birth.
Formation of Sutural/ wormian bones
Unusual centers of ossification
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Pre-Natal Growth
Osification centers appear around 8th week IU.
Fontanelles Close at various times- 2 months to 2 years
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Fontanelles
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Pre-Natal Growth -Control of Morphogenesis
3 questions posed by Van Limborgh:
Relationship between skull and primordia of other organs?
Co-ordination of endochondral and intramembranous ossification?
Co-ordination of growth of skull and other organs?
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Pre-Natal Growth -Control
Intrinsic genetic factors
Epigenetic factors
Environmental factors
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Intrinsic Genetic control Local epigenetic factors
Cranial Cranial differentiation differentiation
General epigenetic factors Local Environmental factors General Environmental factors
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Pre-Natal Growth -Control
Shift of belief:Genetic influence
Epigenetics
Examples- Primordia of eye. - Brain.
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Intrinsic Genetic control Local epigenetic factors
Cranial Cranial differentiation differentiation
General epigenetic factors Local Environmental factors General Environmental factors
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Post-Natal Growth Related to Growth of the Brain Maximum growth upto the 5th year of life – (91% as shown by Davenport)
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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
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Sicher’s Theory Intrinsic Genetic control Local epigenetic factors
Desmocranial Desmocranial Growth Growth
General epigenetic factors Local Environmental factors General Environmental factors
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Post-Natal Growth
Scott’s theory
Inherent growth controlling factors present in Cartilages & Periosteum.
Sutures respond secondarily
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Post-Natal Growth Intrinsic Genetic control
Chondrocranial Chondrocranial Growth Growth
Local epigenetic factors General epigenetic factors
Desmo- Sutures cranial Periosteal Growth growth
Local Environmental factors General Environmental factors www.indiandentalacademy.com
Post-Natal Growth Moss’ FMH
Intrinsic Genetic control Local epigenetic factors
Desmocranial Desmocranial Growth Growth
General epigenetic factors Local Environmental factors General Environmental factors www.indiandentalacademy.com
Post-Natal Growth Sicher – Intrinsic control Hydrocephalus, anencephaly, microcephaly
Scott – Cartilage not responsive to pressure or tension, but intra membranous bone is.
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Post-Natal Growth
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Post-Natal Growth ď °
Synchondrosis
Sutures
Sarnat, Burdi, Baume, Petrovic etc. Also explains why growth of cranial base is less influenced by brain growth than growth of Cranial vault - Van Limborgh
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Post-Natal Growth Moss’ explanation for brain growth controlling growth of the cranium‌ Hydrocephalus, synostosis
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Post-Natal Growth V A U L T
Brain B A S E www.indiandentalacademy.com
Post-Natal Growth Van Limborgh's Summarization:1.
Intrinsic control of growth is exhibited at synchondroses
2.
Intrinsic control of sutural growth is less
3.
Synchondroses should be considered as Growth centre
4.
Sutural growth controlled by both cartilaginous growth and growth of other structures.
5.
Periosteal bone growth (vault) controlled epigenetically by adjacent structures
6.
Growth of cranial vault also controlled by local environmental factors (muscle forces inclusive) www.indiandentalacademy.com
Chondrocranial Chondrocranial Growth Growth
Intrinsic Genetic control Local epigenetic factors General epigenetic factors
Desmocranial Desmocranial Growth Growth
Local Environmental factors General Environmental factors
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Post-Natal Growth Growth of the cranial vault – direct influence of Neurocranial capsule
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New deposition on flat surfaces Endosteal surfaces- resorptive Increases overall thickness- expands medullary spaces.
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Post-Natal Growth Thickening not uniform:Inner table Brain Outer table
mechanical influences and functional stresses
Growth of the frontal sinus (Benninghoff)
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Post-Natal Growth Arc of curvature of the whole bone decreases
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Post-Natal Growth 90% of cranial vault growth complete by 5-6 yrs In accordance with -Scammon’s curve - Cephalocaudal Gradient.
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Clinical Implications ď °
Distortion of head during birth – Fontanelles
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Clinical Implications
Synostosis syndromes Courzon’s syndrome Apert’s syndrome
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Clinical Implications ď °
Other conditions – Hydrocephalus, Anencephaly, Microcephaly
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Clinical Implications
Various conditions – cretinism, progeria, trisomy 21, cleidocranial dysostosis, Anterior fontanelles remain open Bossing of forehead Brachycephalic skull
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Clinical Implications ď °
Herniation of dura mater into the nose
Dura remains in contact with the ectoderm in the region of the anterior neuropore. Ventral bending of the fronto-nasal process brings this junction close to the future nose. Nasal capsule forms around this, and the junction sinks forming the foramen caecum
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Clinical Implications The dura then separates from the ectoderm, and foramen caecum closes. If this foramen fails to close, dura can herniate in to the nose. Also formation of dermoid cysts, sinus or encephalocele. www.indiandentalacademy.com
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Clinical Implications ď °
Abnormal external forces applied to the cranial vault, as by headboards, by primitive tribes.
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GROW TH AND DEVELOPMENT OF CRANIAL BASE Dr. Safeena
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Cranial Base Reasonably stable reference structure in cephalometric analysis ď ° Basis to compare and understand abnormal growth patterns ď °
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Functions
Supports & protects the brain & spinal cord
Articulation of skull with vertebral column , mandible & maxilla
Buffer zone between the brain, face & pharyngeal region
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ANATOMY
ANTERIOR CRANIAL FOSSA
MIDDLE CRANIAL FOSSA
POSTERIOR CRANIAL FOSSA
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ANTERIOR CRANIAL FOSSA 1. 2. 3.
Orbital part of frontal bone Cribriform plate of ethmoid Anterior part of the body of sphenoid & lesser wing
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ANTERIOR CRANIAL FOSSA
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CRIBRIFORM PLATE OF ETHMOID
THE SPHENOID BONE Anterior part of the upper surface of its body is termed the JUGUM SPHENOIDALE
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ORBITAL PLATE OF FRONTAL BONE It separates the orbit and its contents from the inferior surface of the frontal lobe of the brain Its antero medial part split into 2 laminae
FRONTAL SINUS
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MIDDLE CRANIAL FOSSA It is deeper than the anterior fossa ď ° 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, ď ° Behind by superior borders of the temporal bones & Dorsum sellae of sphenoid bone
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MIDDLE CRANIAL FOSSA
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MIDDLE CRANIAL FOSSA Centrally
Optic Canal Hypophyseal Fossa
Laterally
Superior Orbital Fissure Foramen Rotundum Foramen Ovale Foramen Spinosum Foramen Lacerum www.indiandentalacademy.com
POSTERIOR CRANIAL FOSSA Largest and deepest of the cranial fossa
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POSTERIOR CRANIAL FOSSA
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POSTERIOR CRANIAL FOSSA VARIOUS FORAMINA FORAMEN MAGNUM JUGULAR FORAMIN INTERNAL ACOUSTIC MEATUS FACIAL CANAL HYPOGLOSSAL CANAL
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PRENATAL GROWTH Cranial base develops by endochondral bone formation
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PRENATAL GROWTH CHONDRIFICATION
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
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PRENATAL DEVELOPEMENT CRANIUM
NEUROCRANIUM
VISCEROCRANIUM
BASICRANIUM
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PRENATAL DEVELOPEMENT At the cellular level
Hyperplasia Hypertrophy Accretion
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PRENATAL DEVELOPEMENT CARTILAGES
PARACHORDAL CARTILAGE
HYPOPHYSEAL CARTILAGE
OTIC CAPSULE
NASAL CAPSULE
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PRIMORDIAL CARTILAGES
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PRENATAL GROWTH PARACHORDAL CARTILAGES Chondrification centers forming around the cranial end of the notocord
Parachodal cartilages fuse with the sclerotomes arising from occipital somites surrounding the neural tube www.indiandentalacademy.com
PRENATAL GROWTH
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PRENATAL GROWTH 2 Hypophyseal cartilages - Postsphenoid Sella turcica Body of the sphenoid (post. Part)
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PRENATAL GROWTH 2 Presphenoid cartilage- Presphenoid bone Body of the sphenoid bone (ant. Part)
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PRENATAL GROWTH Most anteriorly- presphenoid cartilages- Mesethmoid Ossifies into perpendicular plate of ethmoid Upper edge forms crista galli
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PRENATAL GROWTH Orbito sphenoid - Lesser wing Alisphenoid - Greater wing
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PRENATAL GROWTH OTIC CAPSULE Mastoid and petrous portions of the temporal bones Otic capsule does not chondrify.
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PRENATAL GROWTH NASAL CAPSULE- 2nd month i.u Cartilages of nostrils and the nasal septal cartilage ď ° Functional matrix- downward & forward growth ď ° It helps in transferring compressive forces from incisor region to the sphenoid region
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CHODROCRANIAL OSSIFICATION
110 ossification centers in embryonic human skull. Ossification starts in the 4 months
UNOSSIFIED CHONDROCRANIAL REMNANTS – Alae & septum of the nose,
Spheno-occpital & spheno-petrous junctions,
The apex of the petrous bone and
Between the separate parts of the occipital bone www.indiandentalacademy.com
CHODROCRANIAL OSSIFICATION
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OSSIFICATION OCCIPITAL BONE - 7 centres Supranuchal Squamous portion – 2 intramembranous centres ( 8 th week) Infranuchal squamous – 2 endochondral centres (10 th week) (Kerckring centre)
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OCCIPITAL BONE Basioccipital bone – 1 endochondral (11th week) Exoccipital bone – 2 endochondral centres (12 th week)
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OSSIFICATION TEMPORAL BONE - 21 centres Squamous portion-1 intramembranous centre (8 th week)- Zygomatic process Tympanic ring – 4 intramembranous centres (3 th month) Petrosal part – 14 endochondral centres (16th week) Styloid process – 2 endochochondral centres(at birth) Start to fuse during 1st yr of life
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OSSIFICATION ETHMOID BONE – 3 centres Perpendicular plate & crista galli – 1 endochodral centre Lateral labrynths in the nasal cartilages- 2 endochondral centres
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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 www.indiandentalacademy.com
OSSIFICATION VOMER Alae – 2 intramembranous centres
Inferior nasal concha Lamina – 1 endochondral centre
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OSSIFICATION BONE
SITE & NUMBER OF OSSIFICATION INTRAMEMBRANOUS ENDOCHONDRAL
OCCIPITAL (2)
_ Supranuchal squamous (2)
Infranuchal squamous Basilar (1) Exoccipital (2)
TEMPORAL
_ Squamous (1) Tympanic (4)
Petrosal (14) Styloid (2)
ETHMOID
_
Lateral labrynths (2) Perpendicular plate; Crista (1)
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OSSIFICATION BONE
-
SITE & NUMBER OF OSSIFICATION INTRAMEMBRANOUS ENDOCHONDRAL VOMER _ AlAE (2) SPHENOID _ Medial pterygoid Presphenoid (3) plates (2) Postsphenoid (4) Lateral pterygoid Orbitosphenoid (2) plates (2) Alisphenoids (2) Pterygoid hamulus (2 Sphenoidal conchae (2) INFERIOR NASAL CONCHA _ Lamina (1) www.indiandentalacademy.com
CRANIAL BASE ANGULATION Angle at the hypophyseal fossa where prechordal & chordal parts meet each other
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CRANIAL BASE ANGULATION
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PRE NATAL GROWTH 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
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POSTNATAL GROWTH EXPANTION of cranial base occurs by Growth of the cartilage remnants of the chondrocranium- basicranial bones Forces from growing brain
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POSTNATAL GROWTH 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 www.indiandentalacademy.com
POSTNATAL GROWTH FOSSA ENLARGEMENT
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POSTNATAL GROWTH Endocranial compartments- separated by bony elevations • Middle & posterior fossae – petrous elevation •
Olfactory fossae – crista galli
•
Right & left middle fossae – Sphenoidal elevation
•
Right & left anterior & posterior fossae – Longitudinal midline bony ridge
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POSTNATAL GROWTH Fossa expands outward by resorption, Partitions between them enlarge inward by deposition
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POSTNATAL GROWTH The mid ventral segments of cranial base grows more slowly to accommodate the medulla, pons, hypothalamus & optic chiasma Foramen
Drift process
Spinal Cord
Defferential remodelling
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POSTNATAL GROWTH SYNCHONDROSIS- SEEN IN MIDLINE PART OF BASICRANIUM
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POSTNATAL GROWTH SYNCHONDROSIS
A growth centre Bipolar direction of growth
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POSTNATAL GROWTH SPHENO-OCCIPITAL SYNCHONDROSIS Major contributor in the postnatal growth Fuses at 12-13 years in girls and 14-15 years in boys and ossifies at 20 years of age Pressure adapted bone growth mechanism www.indiandentalacademy.com
POSTNATAL GROWTH ď °
Sinus secondarily grows as the body of the sphenoid bone expands keeping constant junction with the moving naso-maxillary complex
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POSTNATAL GROWTH Post border of N-Mcomplex coincides with boundary between ant and middle cranial fossa Secondary displacement effect (Anterior cranial floor , nasomaxillry complex & mandible)
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POSTNATAL GROWTH ď °
Frontal lobe growth completes by 5years.
ď °
Temporal lobes continue to enlarge for several more years and displaces the frontal lobe forward.
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POSTNATAL GROWTH
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CLINICAL IMPLICATIONS Configuration of neurocranium(& brain) determines a person’s head form type - DOLICOCEPHALIC - BRACHYCEPHALIC - MESOCEPHALIC
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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), 7-14 yrs Mixed longitudinal study
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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 N-Ba. www.indiandentalacademy.com
CLINICAL IMPLICATIONS ACHONDROPLASIA Disturbance in endochondral bone formation Deficient growth at the synchondrosis Maxilla is not translated forward This results in abnormal depression of the bridge of the nose Relative midface deficiency www.indiandentalacademy.com
CLINICAL IMPLICATIONS
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CLINICAL IMPLICATIONS ď °
Premature ossification or synostosis of the suture between the presphaenoid and postsphenoid parts of the spheno-occipital suture - depressed nasal bridge and dished face
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CLINICAL IMPLICATIONS
Anomalous development of the presphenoidal elements Excessive separation of orbits and abnormally broad nasal bridge. -HYPERTELORISM
ANENCEPHALY (Absence of calvaria )
Retain acute cranial base flexure
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CLINICAL IMPLICATIONS
INADEQUATE GROWTH OF CHONDROCRANIUM Impacted eruption of third molars
CLIEDOCRANIAL DISOSTOSIS Abnormalities of the skull, teeth, jaws and shoulder girdle
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Abnormalities Of Cleidocranial Disostosis – Kreiborg,bjork& Skeiller (AJOMay; 1981 )
KREIBORG,BJORK & SKIELLER conducted a qualitative screening for abnormal morphological traits in the cranial base. (8 males & 9 females) RESULTS
The anterior and posterior cranial base was shorter and the cranial angle smaller in the syndrome groups Patients shown small pituitary fossae and bulbous dorsum sellae The amount of bone resorption was lesser than normal. www.indiandentalacademy.com
I will praise thee: for I am fearfully and wonderfully made. Psalm CXXXIX 14
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REFERENCES 1. Craniofacial Embryology -G.H.SPERBER 2. Essencials Of Facial Growth -D.H.ENLOW 3. Contemporary orthodontics W.R.PROFFIT 4. Anatomy –Gray 5. Grants Atlas 6. Abnormalities Of Cleidocranial Disostosis – Kreiborg,bjork& Skeiller (Ajo May; 1981 ) 7. Cranial Base Growth For Dutch Boys & Girls – M.Herneberke,b.P. Andersen (Ajo November; 1994 ) www.indiandentalacademy.com
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