GROWTH & DEVELOPMENT OF CRANIAL VAULT AND BASE Anatomy Function Prenatal growth Postnatal growth
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GROWTH & DEVELOPMENT OF CRANIAL VAULT AND BASE ď‚ŹINTRODUCTION
Skull is a blend of the morphogenesis & growth of three skull entities.
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skull Cranial vault/calvaria. 1. Neurocranium Cranial Base 2. The face Orognathofacial complex ( Splanchocranium,viserocranium) 3.
The masticatory appartus(i.m.)
Dentition www.indiandentalacademy.com Neural Crest and Paraxial Mesoderm Tissue.
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The Neurocranium Cranial vault Cranial Base (Desmocranium) Cranial floor The newly expanded associated with the brain. nasal and auditory Intramembranous bone sense organs. of paraxial mesoderm Endochondral bone of origin. neural crest origin. It’s cartilaginous precursor is known as chondrocranium. www.indiandentalacademy.com
Face Orognathofacial complex ď‚ŹBrachial arch structure ď‚ŹIntramemranous bone of neural
crest origin. www.indiandentalacademy.com
ANATOMY Norma Verticalis – Above Norma Basalis – Below Norma Lateralis – Side Norma Occipitalis – Back Norma Frontalis - Front
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ANATOMY Calvaria or brain box - 8 bone 2 Paired 4 Unpaired Parietal Frontal Temporal Occipital Sphenoid Ethmoid
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SUTURE Metopic suture Coronal suture Sagittal suture Lambdoid suture Bregma Lambda
FUNCTION Protection of the brain. www.indiandentalacademy.com
PRENATAL GROWTH ď‚Ź intramembranous ossification.
MEMBRANOUS NEUROCRANIUM
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PRENATAL GROWTH Ectomeninx Duramater
Superficial membrane Vault
Endomeninx Arachnoid
piamater
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Base
PRENATAL GROWTH Capsular mevmbraneEndomeninx – Neural crest origin Ectomeninx – Neural crest and paraxial mesoderm Ectomeninx: Mesoderm – Frontal, Parietal, sphenoid, petrous temporal & occipital. Neural crest – Lacrimal, nasal, squamous temporal, zygomatic, maxilla & mandible www.indiandentalacademy.com
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PRENATAL GROWTH OSSIFICATION SITE
Frontal Bone – Primary centre
Super ciliary arch
– Secondary centres
Zygomatic process, Nasal spine, Trochlear fossa
Parietal bone – Region of Parietalwww.indiandentalacademy.com eminence
PRENATAL GROWTH Occipital bone (Squamous part) – Just above superior nuchal line
Temporal bone (Squamous part) – Root of zygoma
Tympanic ring of temporal bone – 4 centers in lateral wall of tympanum
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FONATANELLES At birth ,skull bones separated by
loose connective tissue. 6 in no. Close at various times 2 months to 2 years
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FONATANELLES Postnatal growth results narrowing of
suture and elimination of fontanelles.
Posterolateral fonatanelles
Anterior
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posterior
POSTNATAL GROWTH
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Endosteal surface are resorptive . The ectocranial surface are depository in nature. Remodeling allow for change in contour.
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POSTNATAL GROWTH ď‚Ź Arc of curvature of whole bone decrease and bone
becomes flatter .
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POSTNATAL GROWTH Only the inner aspects of frontal bone can be used as stable reference point for growth studies from age 7 yrs. Onwards.
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CALVARIAL GROWTH Suture growth-major mechanism. 2. Remodeling/ surface apposition-after 4 yrs. 3. Centrifugal displacement by the expanding brain (FMH) 1.
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GROWTH & DEVELOPMENT OF CRANIAL BASE
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ANATOMY OF CRANIAL BASE
ANTERIOR CRANIAL FOSSA
MIDDLE CRANIAL FOSSA
POSTERIOR CRANIAL FOSSA
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ANTERIOR CRANIAL FOSSA 1. Orbital plate of frontal
bone 2. Cribriform plate of
ethmoid bone. 3. Anterior part of the body of sphenoid & lesser wing of sphenoid. www.indiandentalacademy.com
CRIBRIFORM PLATE OF ETHMOID It separates the fossa from nasal cavity & forms the roof of the nasal cavity. A median crest like elevation -CRISTA GALLI THE SPHENOID BONE Anterior part of the upper surface of its body is termed the JUGUM SPHENOIDALE www.indiandentalacademy.com
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 www.indiandentalacademy.com
MIDDLE CRANIAL FOSSA 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 the sphenoid and the body of the sphenoid, Behind by superior borders
of the temporal bones & Dorsum sellae of sphenoid bone www.indiandentalacademy.com
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 Anteriorly – Dorsum sellae & body of the sphenoid Posteriorly –Squamous part of the occipital bone Laterally – Petrous & mastoid parts of temporal bone
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POSTERIOR CRANIAL FOSSA VARIOUS FORAMINA FORAMEN MAGNUM JUGULAR FORAMIN INTERNAL ACOUSTIC MEATUS HYPOGLOSSAL CANAL
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CRANIAL BASE FUNCTIONS Supports & protects the brain & spinal cord. Articulation of skull with vertebral column ,
mandible & maxilla. Buffer zone between the brain, face &
pharyngeal region. www.indiandentalacademy.com
PRENATAL GROWTH Cranial base develops by endochondral bone formation
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PRENATAL GROWTH CHONDRIFICATION Mesenchyme
paraxial mesoderm and
neural crest . Form ECTOMENINGEAL CAPSULE . Earliest evidence of skull formation.
Mesenchyme Starting on day 40 i.u. Cartilage www.indiandentalacademy.com
GROWTH OF CRANIAL BASE (proffit) Cartilages (initially)
Endochondral ossification Bone. Midline structure. Moves laterally ,sutures growth & surface remodeling becomes prominent. www.indiandentalacademy.com
GROWTH OF CRANIAL BASE (MOYER) 1. Complex balance among sutural growth. 2. Elongation at synchondrosis. 3. Extensive cortical drift. 4. Remodeling.
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PRENATAL GROWTH CARTILAGES
PARACHORDAL CARTILAGE
HYPOPHYSEAL / POSTSPHENOID CARTILAGE
TRABECULAR
OTIC CAPSULE
NASAL CAPSULE
/ PRESPHENOID CARTILAGES.
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PRENATAL GROWTH
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PRENATAL GROWTH PARACHORDAL CARTILAGES ď‚Ź The sclerotomes cartilage -four occipital somites.
first part of skull to develop foramen magnum boundaries occipital bone (basilar and condylar part)
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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 Orbito sphenoid Lesser wing Alisphenoid - Greater wing Optic capsule not chondrify.
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PRENATAL GROWTH OTIC CAPSULE Mastoid and petrous portions of the temporal bones
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PRENATAL GROWTH MESETHMOID CARTILAGES
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PRENATAL GROWTH NASAL CAPSULE -
Nostril cartilages Nasal septal cartilage
Nasal septal cartilage – Functional matrix
Midface growth
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CHODROCRANIAL OSSIFICATION ď‚Ź110 ossification centers in embryonic
human skull. Ossification starts in the 4 months
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CHODROCRANIAL OSSIFICATION 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
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CHODROCRANIAL OSSIFICATION
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OSSIFICATION occipital bone – 7 centres Intramembranous Endochondral ossification centre ossification centre Supranuchal squamous - 2 Infranuchal squamous - 2 Basilar - 1 Exoccipital - 2
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OSSIFICATION temporal bone -21 centers Intramembranous Endochondral ossification centre ossification centre Squamous portion -1 Petrosal part - 14 Tympanic ring - 4
Styloid process - 2
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OSSIFICATION ETHMOID BONE – 3 endochondral centres Perpendicular plate & crista galli – 1 Lateral labyrinths - 2
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OSSIFICATION sphenoid - 19 Intramembranous ossification centres Medial pterygoid plates – 2 Lateral pterygoid plates -2
centres Endochondral ossification centres Presphenoid – 3 Postsphenoid – 4 Orbitosphenoids - 2 Alisphenoids - 2 Pterygoid hamuli - 2
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OSSIFICATION VOMER Alae – 2 intramembranous centres
Inferior nasal concha Lamina – 1 endochondral centre Sphenoidal conchae -2 endochondral centre
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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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CRANIAL BASE ANGULATION
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PRE NATAL GROWTH Highly Uneven Anterior cranial base increases its length and width by 7 folds( 10th & 40thweek of I.U) Posterior cranial base grows only 5 fold www.indiandentalacademy.com
POSTNATAL GROWTH Cranial base acts as a template from which the face develops. Suture growth is unidirectional. So remodeling is requried.
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POSTNATAL GROWTH
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POSTNATAL GROWTH ď‚Ź The mid ventral segments of cranial base grows
more slowly than the floor of the lateral located fossae. ď‚Ź To accommodate the medulla,pons,hypothalamus
& optic chiasma. Foramen Spinal Cord
Drift process Differential remodelling
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POSTNATAL GROWTH SYNCHONDROSIS - They are a retention left from the primary cartilages of the chondrocranium after the endochondral ossification centers appear during fetal development.
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POSTNATAL GROWTH SYNCHONDROSIS – Fetal & early postnatal peroids. 1. Spheno-ethmoidal synchondrosis 2. Inter-spenoidal synchondrosis - before birth 3. Spheno-occipital synchondrosis
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POSTNATAL GROWTH SPHENO-OCCIPITAL SYNCHONDROSIS Major contributor in the postnatal growth. Fuses at 12-13 years in girls & 14-15 years in boys and ossifies at 20 years of age www.indiandentalacademy.com
POSTNATAL GROWTH Sinus secondarily grows as the body of the sphenoid bone expands with the moving naso-maxillary complex
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POSTNATAL GROWTH ZONES OF SYNCHONDROSIS 1. Familial reserve zone 2. Cell division zone 3. Hypertrophic zone 4. Calcified zone
A growth centre Bipolar direction of growth
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POSTNATAL GROWTH Middle cranial fossa & it’s neural contents Secondary displacement effect (Anterior cranial floor , nasomaxillry complex & mandible)
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POSTNATAL GROWTH Frontal lobe growth completes by 5years. 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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Craniofacial Embryology
-G.H.SPERBER Essentials Of Facial Growth -D.H.ENLOW Anatomy –Gray Contemporary orthodontics W.R.PROFFIT
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