GROWTH AND DEVELOPMENT OF CRANIUM

ANDMAXILLA

CONTENTS• INTRODUCTION• MECHANISM OF BONE GROWTH• CRANIUM• CALVARIA• GROSS ANATOMY• PRENATAL GROWTH• OSTEOGENESIS• FONTANELLES• CRANIAL BASE• ANATOMY• PRENATAL GROWTH• CHONDRIFICATION CENTRES

• SUTURES • SYNCHONDROSIS• CRANIAL BASE ANGULATION• ANOMALES• MAXILLA • EMBRYOLOGY• PALATE• POSTNATAL REMODELLING• THEORIES OF GROWTH• ANOMALIES

INTRODUCTION DEFINITIONS

• GROWTH ROBERT E MOYERS HAS DEFINED GROWTH

AS NORMAL CHANGES OCCURING IN AMOUNT OF SUBSTANCES. ACCORDING TO HIM, GROWTH IS QUANTITATIVE ASPECT OF BIOLOGIC DEVELOPMENT MEASURED PER UNIT TIME.

• DEVELOPMENT IT REFERS TO ALL THE NATURALLY

OCCURING UNIDIRECTIONAL CHANGES IN THE LIFE OF AN INDIVIDUAL FROM ITS EXISTENCE AS A SINGLE CELL TO ITS ELABORATION AS A MULTIFUNCTIONAL UNIT TERMINATING TO DEATH.

BEFORE GOING AHEAD WITH CRANIUM AND MAXILLAE LETS KNOW THE BASICS OF

MECHANISM OF BONE GROWTH

MECHANISM OF BONE GROWTH

ALL BONE GROWTH IS A COMPLICATED MIXTURE OF TWO BASIC PROCESSES, DEPOSITION AND RESORPTION, WHICH ARE CARRIED OUT BY GROWTH FIELDS COMPRISED OF THE SOFT TISSUES INVESTING THE BONE. BECAUSE THE FIELDS GROW AND FUNCTION DIFFERENTLY ON DIFFERENT PARTS OF THE BONE, THE BONE UNDERGOES REMODELING (I.E, SHAPE CHANGE). WHEN THE AMOUNT OF DEPOSITION IS GREATER THAN THE RESORPTION, ENLARGEMENT OF THE BONE NECESSITATES ITS DISPLACEMENT (I.E., ITS PHYSICAL RELOCATION) IN CONCERT WITH OTHER BONE DISPLACEMENT.

A) DEPOSITION AND RESORPTION

ON ONE SIDE OF A BONY CORTEX NEW BONE IS ADDED, ON THE OTHER SIDE, BONE IS TAKEN AWAY. DEPOSITION OCCURS ON THE SURFACE FACING THE DIRECTION OF GROWTH, WHILE RESORPTION IS SEEN ON THE SURFACE FACING AWAY. THE RESULT IS A PROCESS TERMED CORTICAL DRIFT. A GRADUAL MOVEMENT OF THE GROWING AREA OF THE BONE.

BONE DOES NOT ADD EVEN ACCRETIONS ON ITS OUTSIDE SURFACES AS IN THE CONCENTRIC RINGS OF A TREE.

THE COMPLEX MORPHOLOGIES OF FACIAL BONES MAKE UNIFORM ENLARGEMENT IMPOSSIBLE AND DIFFERENTIAL GROWTH A NECESSITY; THUS, SOME AREAS GROW MORE RAPIDLY AND SOME OUTSIDE SURFACES SHOW RESORPTION. ENLOW'S "V" PRINCIPLE IS USEFUL IN UNDERSTANDING DEPOSITION AND RESORPTION IN COMPLICATED REMODELING DURING GROWTH IN LENGTH (E.G THE ENDS OF LONG BONES OR THE NECK OF THE MANDIBLE)

The "V" principle (top). Many facial bones or parts of bones have a "V" shape. Note that deposition ( + ) occurs on the inner side and resorption ( - ) on the outer. The "V" moves from A to B as the overall dimension increases (i.e, movement is toward the wide end of the "V"). Thus, simultaneous growth movement and enlargement occur.

(Bottom) note that the diameter at A is reduced as the broad part of the bone is relocated to B. Wider parts become narrower by periosteal resorption and endosteal deposition.

B) GROWTH FIELDS

ALL SURFACES, INSIDE AND OUTSIDE, OF EVERY BONE ARE COVERED BY AN IRREGULAR PATTERN OF "GROWTH FIELDS" COMPRISED OF VARIOUS SOFT-TISSUE OSTEOGENIC MEMBRANES OR CARTILAGES. BONE DOES NOT GROW ITSELF, IT IS GROWN BY THIS ENVIRONMENT OF SOFT-TISSUE GROWTH FIELDS. THE GENETIC PROGRAM FOR BONE GROWTH IS NOT CONTAINED WITHIN THE HARD BONE TISSUE; RATHER, THE DETERMINANTS OF BONE GROWTH RESIDE IN THE BONE'S INVESTING SOFT TISSUES~MUSCLES, INTEGUMENT, MUCOSA, BLOOD VESSELS, NERVES, CONNECTIVE TISSUE, THE BRAIN, ETC. ANY BONE HAS BOTH RESORPTIYE AND DEPOSITORY FIELDS OVER ALL ITS INSIDE AND OUTSIDE CORTICAL SURFACES.

SOME GROWTH FIELDS HAVING SPECIAL ROLES IN THE GROWTH OF PARTICULAR BONES ARE CALLED G RO WTH SITES . THESE INCLUDE. THE MANDIBULAR CONDYLE, THE MAXILLARY TUBEROSITY, THE SYNCHONDROSES OF THE BASICRANIUM, THE SUTURES, AND THE ALVEOLAR PROCESSES. THESE SPECIAL GROWTH SITES DO NOT CAUSE ALL OF THE GROWTH IN THEIR BONE, OR CARRY OUT EVEN MOST OF THE GROWTH PROCESS OF A PARTICULAR BONE, FOR ALL OTHER INSIDE AND OUTSIDE SURFACES MUST ACTIVELY PARTICIPATE AS WELL IN THE OVERALL GROWTH PROCESS.

SOME GROWTH SITES HAVE BEEN CALLED" GROWTH CENTERS," A TERM WHICH IMPLIES THAT A SPECIAL AREA SOMEHOW CONTROLS THE OVERALL GROWTH OF THE BONE. THE TERM "GROWTH CENTER" ALSO IMPLIES THAT THE "FORCE," "ENERGY," OR "MOTOR" FOR A BONE RESIDES PRIMARILY OR SOLELY WITHIN ITS GROWTH CENTER. THIS CONCEPT FINDS SUPPORT WHEN ONE CONSIDERS THE EPIPHYSEAL PLATES OF LONG BONES WHICH CONTINUE THEIR GROWTH AGAINST THE LARGE FORCES OF GRAVITY, MUSCLE CONTRACTIONS, ETC.

C) REMO DELING

THIS CONCEPT FINDS SUPPORT WHEN TERMED REMO DELING , INVOLVES SIMULTANEOUS DEPOSITION AND RESORPTION ON ALL INNER AND OUTER SURFACES OF THE ENTIRE BONE. REMODELING, A BASIC 'PART OF THE GROWTH PROCESS, NOT ONLY PROVIDES REGIONAL CHANGES IN SHAPE, DIMENSIONS, AND PROPORTIONS, IT ALSO PRODUCES REGIONAL ADJUSTMENTS THAT ADAPT TO THE DEVELOPING-FUNCTION OF THE BONE AND ITS VARIOUS GROWING SOFT TISSUES,

THERE ARE FOUR KINDS OF REMODELING IN BONE TISSUES:

•(I) BIOCHEMICAL REMODELING, INVOLVING CONTINUOUS DEPOSITION AND REMOVAL OF IONS TO MAINTAIN MINERAL HOMEOSTASIS;

•(2) GROWTH REMODELING, THE CONSTANT REPLACEMENT OF BONE DURING CHILDHOOD;

•(3) HAVERSIAN REMODELING, THE SECONDARY PROCESS OF CORTICAL RECONSTRUCTION AS PRIMARY VASCULAR BONE IS REPLACED; AND

•(4) THE REGENERATION AND RECONSTRUCTION OF BONE DURING AND FOLLOWING PATHOLOGY OR TRAUMA.

TO SUMMARIZE, GROWTH REMODELING IS PACED BY THE GROWTH AND FUNCTIONS OF THE SOFT TISSUES WHICH SURROUND THE BONES. AS THESE SOFT TISSUES GROW AND FUNCTION THEY

•SHAPE THE BONE, WHICH ADAPTS TO THE CHANGING FUNCTIONAL ACTIONS EXERTED ON IT;

•RELOCATE PARTS OF THE BONE PRODUCING, AS A RESULT, A PROGRESSIVELY LARGER WHOLE BONE; AND

•CARRY OUT REGIONAL ADJUSTMENTS TO MAINTAIN CONTINUOUS FITTING TOGETHER OF THE SEPARATE BONES WITHIN THEIR GROWING SOFT ·TISSUE ENVIRONMENT.

D) GROWTH MOVEMENTSTWO KINDS OF GROWTH MOVEMENTS ARE SEEN DURING THE ENLARGEMENTOF CRANIOFACIAL BONES: CORTICAL DRIFT AND DISPLACEMENT.

DRIFT IS GROWTH MOVEMENT (RELOCATION OR SHIFTING) OF AN ENLARGING PORTION OF A BONE BY THE REMODELING ACTION OF ITS OSTEOGENIC TISSUES, WHILE DISPLACEMENT IS A PHYSICAL MOVEMENT OF THE WHOLE BONE AS IT REMODELS.

1)DRIFT-COMBINATIONS OF DEPOSITION AND RESORPTION RESULT IN GROWTH MOVEMENT TOWARD THE DEPOSITORY SURFACE. DRIFT IS SEEN WITH REMODELING ENLARGEMENT AND IS PRODUCED BY THE DEPOSITION OF THE NEW BONE ON ONE SIDE OF THE CORTICAL PLATE, WHILE RESORPTION OCCURS ON THE OPPOSITE SIDE. IF AN IMPLANT IS PLACED ON THE SURFACE OF THE DEPOSITORY SIDE OF A BONY CORTEX, IT BECOMES GRADUALLY EMBEDDED IN THE CORTEX AS NEW BONE .

CONTINUES TO FORM OVER THAT SURFACE AND AS RESORPTION OCCURS ON THE OPPOSITE SURFACE. IN TIME THE IMPLANT BECOMES RELOCATED FROM ONE SIDE OF THE CORTEX TO THE OTHER, NOT BECAUSE OF ITS OWN MOVEMENT (THE IMPLANT IS IMMOBILE), BUT BECAUSE OF THE DRIFT OF THE BONE AROUND IT.

2) DISPLACEMENT-DISPLACEMENT, ON THE OTHER HAND, IS MOVEMENT OF THE WHOLE BONE AS A UNIT. AS A BONE IS CARRIED AWAY FROM ITS ARTICULATION WITH OTHER BONES, GROWTH REMODELING SIMULTANEOUSLY MAINTAINS RELATIONSHIPS OF THE BONES TO EACH OTHER. FOR EXAMPLE, AS THE ENTIRE MANDIBLE IS DISPLACED FROM ITS ARTICULATION IN THE GLENOID FOSSA, IT IS NECESSARY FOR THE CONDYLE AND RAMUS TO GROW UPWARD AND BACKWARD TO MAINTAIN RELATIONSHIPS.

AS THE CONDYLAR NECK, CORONOID PROCESS, AND RAMUS REMODEL TO ACCOMMODATE THE DISPLACEMENT, THEY ALSO GROW IN SIZE AND SUSTAIN BASIC SHAPE. THIS ENTIRE PROCESS IS CALLED PRIMARY DISPLACEMENT, THAT IS, DISPLACEMENT ASSOCIATED WITH THE BONE'S OWN ENLARGEMENT. SECONDARY DISPLACEMENT IS MOVEMENT OF A BONE RELATED TO ENLARGEMENT OF OTHER BONES.

DRIFT AND DISPLACEMENT OCCUR TOGETHER AND COMPLEMENT EACH OTHER I .E THEY MOVE IN THE SAME DIRECTION) OR THEY MAY TAKE PLACE IN CONTRASTING DIRECTIONS.

CRANIUM

• THE DEVELOPMENT 0F SKULL, COMPRISING BOTH THE CRANIUM AND MANDIBLE, IS A BLEND OF 3 MAIN SKULL ENTITIES-

1) NEUROCRANIUM - SKULL VAULT OR CALVARIA OR DESMOCRAIUM - CRANIAL BASE OR CHONDROCRNIUM. 2) FACE OR OROGNATHOFACIAL COMPLEX

. SPLANCHNOCRANIUM

OR VISCEROCRANIUM

3) MASTICATORY APPARATUS.

THREE SKULL ENTITIES ARISE FROM

I)NUERAL CREST CELLS

II)PARAXIAL MESODERM TISSUE

CALVARIA

GROSS ANATOMY

NORMA VERTICALIS

NORMA OCCIPITALIS

NORMA LATERALIS

NORMA FRONTALIS

3 MAJOR TYPES OF GROWTH AT CELLULAR LEVEL

ACCRETIONARY - INCREASE IN INTERCELLULAR

MATRIX

MULTIPLICATIVE - HYPERPLASIA

DIMENSIONAL - HYPERTROPHY OR AUXETIC

THE MESENCHYME THAT GIVES RISE TO THE VAULT OF NEUROCRANIUM IS ARRANGED FIRST AS CAPSULAR MEMBRANE AROUND THE DEVELOPING BRAIN.

CAPSULAR MEMBRANE

MEMBRANE

INNER ENDOMENIX OUTER ECTOMENIX

NUERAL CREST ORIGIN

MIXED PARAXIAL MESODERM & NUERAL

CREST ORIGIN

ENDOMENIX

ENDOMENIX

2 LEPTOMENINGEALCOVERING OF

BRAINPIAMATTER ARACHNOID

ECTOMENIX

ECTOMENIX

INNER DURA OUTER DURA

OSTEOGENESIS

• ECTOMENIX FORMING SKULL VAULT IS – INTRAMEMBRANOUS.

• ECTOMENIX FORMING FLOOR OF BRAIN IS -- ENDOCHONDRAL.

ENDOCHONDRAL BONE FORMATION

DURING ENDOCHONDRAL BONE FORMATION, THE ORIGINAL MESENCHYMAL TISSUE FIRST BECOMES CARTILAGE. ENDOCHONDRAL BONE FORMATION IS A MORPHOGENETIC ADAPTATION PROVIDING CONTINUED PRODUCTION OF BONE IN SPECIAL REGIONS THAT INVOLVE RELATIVELY HIGH LEVELS OF COMPRESSION. THUS, IT IS FOUND IN THE BONES ASSOCIATED WITH MOVABLE JOINTS AND SOME PARTS OF THE BASICRANIUM. CARTILAGE CELLS HYPERTROPHY, THEIR MATRIX BECOMES CALCIFIED, THE CELLS DEGENERATE, AND OSTEOGENIC TISSUES INVADE THE DYING AND DISINTEGRATING CARTILAGE AND REPLACE IT. ENDOCHONDRAL BONE IS NOT FORMED DIRECTLY FROM CARTILAGE; IT INVADES CARTILAGE AND REPLACES IT.

INTRAMEMBRANOUS BONE FORMATION

IN INTRAMEMBRANOUS BONE FORMATION, THE UNDIFFERENTIATED MESENCHYMAL CELLS OF THE MEMBRANOUS CONNECTIVE TISSUE CHANGE TO OSTEOBLASTS AND ELABORATE OSTEOID MATRIX. THE MATRIX OR INTERCELLULAR SUBSTANCE BECOMES CALCIFIED, AND BONE RESULTS. BONE TISSUES LAID DOWN BY THE PERIOSTEUM, ENDOSTEUM, SUTURES, AND THE PERIODONTAL MEMBRANE (LIGAMENT) ARE ALL INTRAMEMBRANOUS IN FORMATION.

INTRAMEMBRANOUS OSSIFICATION IS THE PREDOMINANT MODE OF GROWTH IN THE SKULL, EVEN IN COMPOSITE "ENDOCHONDRAL" ELEMENTS, SUCH AS THE SPHENOID AND MANDIBLE, WHERE ENDOCHONDRAL AND INTRAMEMBRANOUS GROWTH OCCUR IN THE SAME BONE. THE BASIC MODES OF FORMATION (OR RESORPTION) ARE SIMILAR, REGARDLESS OF THE KIND OF MEMBRANE INVOLVED.

BONE TISSUE SOMETIMES IS CLASSIFIED AS "PERIOSTEAL" OR "ENDOSTEAL“ ACCORDING TO ITS SITE OF FORMATION. PERIOSTEAL BONE ALWAYS IS OF INTRAMEMBRANOUS ORIGIN, BUT ENDOSTEAL BONE MAY BE EITHER INTRAMEMBRANOUS OR ENDOCHONDRAL IN ORIGIN, DEPENDING ON THE SITE AND MODE OF FORMATION. INTRAMEMBRANOUS BONE GROWTH MAY BE SUMMARIZED AS FOLLOWS:

•INTRAMEMBRANOUS BONE GROWTH OCCURS IN AREAS OF TENSION. THE MEMBRANES (PERIOSTEUM, SUTURES, PERIODONTIUM) HAVE THEIR OWN INTERNAL DEPOSITION AND REMODELING PROCESSES.

THE MEMBRANE GROWS OUTWARD RATHER THAN JUST BACKING OFF AS BONE IS LAID DOWN BEHIND IT. AS IT DOES SO IT UNDERGOES EXTENSIVE FIBROUS CHANGES IN ORDER TO MAINTAIN CONTINUITY AMONG THE PERIOSTEUM, MUSCLE INSERTIONS, AND THE BONE ITSELF.

THEREFORE, THERE IS CONSTANT DEPOSITION AND RESORPTION ON THE BONE SURFACES AS PART OF MEMBRANOUS REMODELING AND RELINKING PROCESSES.

SEVERAL PRIMARY AND SECONDARY OSSIFICATION CENTRES DEVELOP IN OUTER LAYER OF ECTOMENIX TO FORM INDIVIDUAL BONES.

MESODERMALLY DERIVED ECTOMENIX GIVES RISE TO- - FRONTAL BONE - PARIETAL BONE - SPHENOID BONE - PETROUS TEMPORAL BONE - OCCIPITAL BONE

NUERAL CREST ORIGIN ECTOMENIX GIVES RISE TO

- LACRIMALBONE- NASAL BONE - SQUAMOUS TEMPORAL BONE- MAXILLARY BONE- MANDIBULAR BONE- ZYGOMATIC BONE

O CCIPITAL BO NE - 7 centres

Supranuchal Squamous portion – 2 intramembranous centres

. ( 8th week) Infranuchal squamous – 2 endochondral centres (10th week) Basioccipital bone – 1 endochondral centre (11th week) Exoccipital bone – 2 endochondral centres (12 th week)

TEMPO RAL BO NE - 21 centres

Squamous portion-1 intramembranous centre (8 th week) Tympanic ring – 4 intramembranous centres (3 th month) Petrosal part – 14 endochondral centres (16th week)

ETHMO ID BO NE – 3 c e ntre s

Perpendicular plate & crista galli – 1 endochondral centre

Lateral labrynths in the nasal cartilages - 2 endochondral centres

SPHENO ID BO NE – 19 centres Basisphenoid – 3 presphenoid & 4 postsphenoid endochondral centres Greater wings – 2 centres Lesser wings - 2 centres Medial pterygoid plates – 2 intramembranous centres Lateral pterygoid plates – 2 intramembranous centres Sphenoidal conchae – 2 endochondral centres

EARLIEST CENTRES OF OSSIFICATON FIRST APPEARS AT 7TH AND 8TH WEEK POST CONCEPTION.

THE MESENCHYME BETWEEN THE BONES DEVELOPS FIBERS TO FORM SYNDESMOTIC ARTICULATIONS.

MEMBRANOUS MESENCHYME FORMS PERIOSTEUM.

FONTANELLES• AT BIRTH THE INDIVIDUAL CALVARIAL BONES

ARE SEPERATED BY SUTURE AND FONTANELLES.

• ALSO CALLED AS “SOFT SPOTS”• SIX IN NUMBER

• ANTERIOR - BREGMA- CLOSES BY 18 MONTHS.

• POSTERIOR- LAMBDA- CLOSES BY 2 MONTHS

• 2 ANTEROLATERAL - PTERION- 3 MONTHS

• 2 POSTEROLATERAL - ASTERION- 2 YEARS.

FONTANELLES

THE PRECOCIOUS DEVELOPMENT OF BRAIN THE PRECOCIOUS DEVELOPMENT OF BRAIN DETERMINES THE PREDOMINANE OF NUEROCRANIUM DETERMINES THE PREDOMINANE OF NUEROCRANIUM OVER FACIAL PORTION. OVER FACIAL PORTION.

NUEROCRANIUM : FACENUEROCRANIUM : FACEAT BIRTH 8 : 1AT BIRTH 8 : 122NDND YEAR 6 : 1 YEAR 6 : 155TH TH YEAR 4 : 1 YEAR 4 : 1ADULT 2 : 1 TO 2.5 : 1ADULT 2 : 1 TO 2.5 : 1

NUEROCRANIUMNUEROCRANIUM

AT BIRTH 25% OF ITS GROWTHAT BIRTH 25% OF ITS GROWTH66TH TH MONTH 50% MONTH 50%2 YEARS 75% 2 YEARS 75% 10 YEARS 95%10 YEARS 95%

FACE- ONLY 65% AT 10 YEARS.FACE- ONLY 65% AT 10 YEARS.

CRANIAL BASE

GROSS ANATOMY

DURING THE LATE SOMITE PERIOD, THE DURING THE LATE SOMITE PERIOD, THE OCCPITAL SCLEROTOMAL MESENCHYME OCCPITAL SCLEROTOMAL MESENCHYME CONCENTRATES AROUND THE NOTOCHORD CONCENTRATES AROUND THE NOTOCHORD UNDERLYING THE DEVELOPING HINDBRAIN.UNDERLYING THE DEVELOPING HINDBRAIN.

FROM THIS, MESENCHYMAL CONCENTRATIONS FROM THIS, MESENCHYMAL CONCENTRATIONS EXTEND CEPHALYCALLY FORMING FLOOR OF EXTEND CEPHALYCALLY FORMING FLOOR OF BRAIN.BRAIN.

CONVERSION OF THE ECTOMENIX CONVERSION OF THE ECTOMENIX MESENCHYME INTO CARTILAGE CONSTITUTES MESENCHYME INTO CARTILAGE CONSTITUTES THE BEGINNING OF “CHONDROCRANIUM”, THE BEGINNING OF “CHONDROCRANIUM”, STARTING ON 40STARTING ON 40THTH DAY AFTER CONCEPTION. DAY AFTER CONCEPTION.

CHONDRIFICATION CENTRE

• PARACHORDAL CARTILAGE.• HYPOPHYSIAL CARTILAGE. • BASISPHENOID CARTILAGE.• PRESPHENOID CARTILAGE.• ORBITOSPHENOID CARTILAGE. • ALISPHENOID CARTILAGE.

• CAPSULES• -NASAL CAPSULE• -OTIC CAPSULE

• PARACHORDAL CARTILAGE – BOUNDARIES OF FORAMEN MAGNUM

BASILAR AND CONDYLAR PARTS OF OCCIPITAL BONE.

• HYPOPHYSEAL CARTILAGE

GIVES BASISPHENOID CARTILAGE

SELLA TURCICA

POSTERIOR PART OF BODY OF SPHENOID

• PRESPHENOID CARTILAGE

ANT. PART OF BODY OF SPHENOID

• ORBITOSPHENOID

LESSER WING OF SPHENOID

• ALISPHENOD

GREATER WING OF SPHENOID

• NASAL CAPSULE

CARTILAGES OF NOSTRIL

NASAL SEPTAL CARTILAGE

• OTIC CAPSULES

MASTOID AND PETROUS PART OF TEMPORAL BONE

CHONDRIFICATION CENTRES

• BONE - SITE & NUMBER OF OSSIFICATION . . . CENTRE

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 CONCHA(2)

• INFERIOR NASAL LAMINA (1)

CONCHA _

PRIMORDIAL CARTILAGES

CRANIAL BASE ANGULATION

• THE CENTRAL REGION OF THE CRANIAL BASE IS COMPOSED OF PRECHORDAL PARTS AND CHORDAL THAT MEET AT AN ANGLE AT THE HYPOPHYSIAL FOSSA.

• THE LOWER ANGLE, FORMED BY LINES FROM NASION TO SELLA TO BASION IN THE SAGITTAL PLANE IS CRANIAL BASE ANGLE

• IT VARIES WITH THE STAGE OF

• DEVELOPMENT AS

4 WEEK EMBRYO -154 WEEK EMBRYO -1500°°

7 TO 8 WEEK EMBRYO -1307 TO 8 WEEK EMBRYO -130°°

10 WEEKS EMBRYO -11510 WEEKS EMBRYO -115°°-120-120°°

10-20 WEEKS -12510-20 WEEKS -125°°-130-130°°

THIS ANGULATION IS MAINTAINED THIS ANGULATION IS MAINTAINED POSTNATALLY.POSTNATALLY.

- BETWEEN 6-10 WEEKS, THE WHOLE HEAD IS - BETWEEN 6-10 WEEKS, THE WHOLE HEAD IS RAISED BY EXTENSION OF NECK , LIFTING THE RAISED BY EXTENSION OF NECK , LIFTING THE FACE FROM THE THORAX.FACE FROM THE THORAX.

THIS IS CONCOMITANT WITH PALATAL FUSION.THIS IS CONCOMITANT WITH PALATAL FUSION.

CRANIAL BASE ANGULATION

CRANIAL FLEXURE

- CRANIAL BASE FLEXURE PLACES THE- CRANIAL BASE FLEXURE PLACES THE

FORAMEN MAGNUM DIRECTLY OVER FORAMEN MAGNUM DIRECTLY OVER THE VERTICAL SPINAL CORD THE VERTICAL SPINAL CORD AND ACHIEVES A FORWARD AND ACHIEVES A FORWARD ALIGNMENT OF THE FACE AND ALIGNMENT OF THE FACE AND ORBITS BECAUSE OF HUMAN ORBITS BECAUSE OF HUMAN BIPEDAL POSTURE.BIPEDAL POSTURE.

- GIVES WAY TO GROWING FACE.- GIVES WAY TO GROWING FACE.

- AFFECTS THE MANDIBULAR - AFFECTS THE MANDIBULAR POSITIONING.POSITIONING.

POST NATAL GROWTH

3 MAJOR FACTORS IN DEVELOPENT OF 3 MAJOR FACTORS IN DEVELOPENT OF CRANIUM ARECRANIUM ARE

1.EXPANSION OF INTRACRANIAL 1.EXPANSION OF INTRACRANIAL CONTENT.CONTENT.

2.GROWTH OF SYNDESMOSIS (SUTURES).2.GROWTH OF SYNDESMOSIS (SUTURES).

3.SYNCHONDROSIS.3.SYNCHONDROSIS.

EXPANSION OF INTRACRANIAL CONTENT

• IN CRANIAL DEVELOPMENT, THE CONTENTS INDUCE THE CONTAINER……………….

J.SCHOWING, 1974

GROWTH OF CRANIAL VAULT OCCURS PRIMARILY AS A GROWTH OF CRANIAL VAULT OCCURS PRIMARILY AS A RESULT OF EXPANSION OF INTRACRANIAL CONTENT.RESULT OF EXPANSION OF INTRACRANIAL CONTENT.

AS THE CRANIAL CONTENT EXPANDS IN SIZE, THE AS THE CRANIAL CONTENT EXPANDS IN SIZE, THE CALVARIAL BONES, WHICH ARE ESSENTIALLY FLOATING CALVARIAL BONES, WHICH ARE ESSENTIALLY FLOATING UPON THE DURAMATER, ARE DISPLACED OUTWARDUPON THE DURAMATER, ARE DISPLACED OUTWARD SEPERATIG THE BONES AT THERE SUTURAL MARGINS.SEPERATIG THE BONES AT THERE SUTURAL MARGINS.

SUTURES RESPOND TO THIS SEPERATION (TENSION) BY SUTURES RESPOND TO THIS SEPERATION (TENSION) BY OSTEOGENESIS , DEPOSITING BONE AT THE MARGINS OF OSTEOGENESIS , DEPOSITING BONE AT THE MARGINS OF CALVARIAL BONE.CALVARIAL BONE.

THE OUTER TABLES OF CALVARIA IS ASSOCIATED NOT THE OUTER TABLES OF CALVARIA IS ASSOCIATED NOT ONLY WITH INTRACRANIAL CONTENT, BUT ALSOWITHONLY WITH INTRACRANIAL CONTENT, BUT ALSOWITH SOFT TISSUE ATTACHMENTS.SOFT TISSUE ATTACHMENTS.

SUTURES

• IN THE CLOSEST UNION THERE IS STILL SOME SEPARATE EXISTENCE OF COMPONENT PARTS ; IN THE MOST COMPLETE SEPARATION THERE IS SOME REMINISCENCE OF UNION……

SAMUEL BUTLER

GROWTH OF SYNDESMOSIS

• SUTURS BEHAVE AS SPECIALISED PERIOSTEUM

• SHOWS TENSION ADATED GROWTH, IN RESPONSE TO GROWTH OF BRAIN AS WELL AS A RESULT OF MUSCLE FUNCTION.

• ON THE OTHER HAND, THE BONES OF THE CRANIAL VAULT MUST REMAIN ARTICUALATED THROUGH SUTURES AND, HENCE, ARE OFTEN EQUIPPPED WITH COMPLEX INTERDIGITATION THAT RESIST EXCESSIVE SEPERATION , WHILE AT THE SAME TIME PROVIDING EXTENSIVE SURFCE AREA FOR BONE GROWTH.

METOPIC SUTURES -7 YEARS.METOPIC SUTURES -7 YEARS. SAGITTALSAGITTAL CORONAL 20-40 YEARSCORONAL 20-40 YEARS LAMBDOIDALLAMBDOIDAL OCCIPITOMASTOIDOCCIPITOMASTOID SPHENOTEMPORAL 70 YEARSSPHENOTEMPORAL 70 YEARS SQUAMOUSSQUAMOUS

SYNCHONDROSIS

• ENDOCHONDRAL BONE JUNCTIONS SITES WHERE CARTILAGE IS INTERPOSED BETWEEN CONTIGOUS BONES ARE KNOWN AS SYNCHONDROSIS.

• REMAINS OF CHONDROCRANIUM SEPERATING CENTRES OF OSSIFICATION.

• PRESURE ADAPTED GROWTH.

• POSTNATALLY, THERE ARE FOUR PRIMARY SYNCHONDROSES

1.SPHENOOCCIPITAL – 20-23 YEARS 2.SPHENOETHMOID- 7 YEARS 3.INTERSPHENOID – DISAPPEARS AT BIRTH 4.INTRAOCCIPITAL - 3-5 YEARS

DURING ACTIVE GROWTH OF DURING ACTIVE GROWTH OF SYCHONDROSES BOTH PRIMARY SYCHONDROSES BOTH PRIMARY CENTRES OF OSIFICATION MOVE CENTRES OF OSIFICATION MOVE APART RELATIVE TO MIDDLE OF THE APART RELATIVE TO MIDDLE OF THE SYNCHONDROSIS.SYNCHONDROSIS.

SPHENOOCIPITAL SYNCHONDROSES

• SITUATED AT THE MIDPOINT OF CRANIAL BASE.

• EXCELLENT POSITION TO INFLUENCE DISPLACEMENT OF FACE

ANTERIORLY AND THE OCCIPITAL REGION POSTERIORLY.

• GREATER GROWTH ON OCCIPITAL ASPECT THAN ON ITS SPHENOIDAL

ASPECT.(SPERBER,1976).

• ACTIVE FOR VERY LONG.

• HYPOTHESIS ON GROWTH POTENTIAL OF SYNCHONDROSAL

CARTILAGE MADE IT CLEAR THAT CERTAIN ENVIRONTAL FACTORS

,FOR EG PRESENCE AND MASS OF NUERAL TISSUE AND RELATIVE

DEGREE OF COMPRESSIVE AND TENSILE FORCES DO INFLUENCE THE

SYNCHONDROSES.

• PRIMARY DISPLACEMENT AND ENDOCHONDRAL BONE DEPOSITION.

SYNCHONDROSIS

APPOSITION

HEAD CIRCUMFERENCE

• AT MIDGESTATIONAL PERIOD- 18CM• AT BIRTH - 33CM• 1ST YEAR- 46CM

THEN SLOWS DOWN• 2 YEAR- 49CM• 3 YEARS- 50CM

INCREASE BETWEEN 3 YEARS AND ADULTHOOD IS ONLY 6CM

ANOMALIES OF

DEVELOPMENT

• ABSENCE OF HEAD -ACEPHALY

• ABSENCE OF BRAIN -ANENCEPHALY

• ABSENCE OF SKULL –ACRANIA

• ROOFLESS SKULL -ACALVARIA

• FAILURE OF NORMAL CLEAVAGE OF FOREBRAIN -HOLOPROSENCEPHALY

• CYCLOPIA -SYNOPTHALMIA

CRANIOSYNOSTOSIS

• PREMATURE CLOSURE OF CRANIAL SUTURES.• DEPENDING ON WHICH SUTURE ARE PREMATURELY

SYNOSTOSED.

• NORMOCEPHALY

• DOLICOCEPHALY- IF THE SAGITTAL SUTURE IS INVOLVED, RESTRICTION IN LATERAL GROWTH.

• BRACHICEPHALY- IF THE CORONAL SUTURE IS INVOLVED ,RESTRICTION IN A-P DIRECTION.

• PLAGIOCEPHALY – ASSYMETRICAL SKULL. UNILATERAL CLOSURE OF CORONAL OR LAMBOIDAL SUTURE.

• TRIGONOCEPHALY- PREMATURE CLOSURE OF METOPIC SUTURE, TRIANGULAR CALVARIA

• IN CONDITIONS LIKE CRETINISM , PROGERIA, TRISOMY 21, AND CLEIDOCRANIAL DYSOSTOSIS THERE IS DELAYED MIDLINE OSSIFICAION OF FRONTAL AND SAGGITAL SUTURES OF THE CALVARIA,

• ANTERIOR FONTANELLE MAY REMAIN OPEN INTO ADULT LIFE.

• ENCEPHOLOCELES-

DEFECTS IN CLOSURE OF FORAMEN CAECUM AT THE ETHMOID FRONTAL SUTURE ALLOWING HERNIATION OF THE CRANIAL CONTENTS INTO FACE.

• AFFILICATON OF CARTILAGE GROWTH PRODUCES A REDUCED CRANIAL BASE WITH INCREASED ANGULATION DUE TO LOSS OF FLATTENING EFFECT OF SPHENOCHONDRAL SYNCHONDROSIS.

• RESULTS IN DISHED DEFORMITY OF MIDDLE 1/3RD OF FACIAL SKELETON ACCENTUATED BY A BULGING OF NUEROCRANIUM.

• SEEN IN ACHO NDRO PLASIA, CRETINISM AND DO WNS SYNDRO ME

SYNDROMES

• 13 TRISOMY SYNDROME.

EXTRA CHROMOSOMES 13.

CLEFT LIP AND PALATE

MICROCEPHALY WITH SEVERES BRAIN MALFORMATIONS.

• TRISOMY 18 SYNDROME (EDWARDS SYNDROME)

• PROMINENT LARGE FOREHEAD.

MAXILLA

GROSS ANATOMY

• FRONTAL PROCESS

• ORBITAL SURFACE

• NASAL NOTCH

• ANS

• ZYGOMATIC BONE

• CANINE EMINENCE

• ALVEOLAR PROCESS

PRENATAL GROWTH

A one month embryo will have no real face, but A one month embryo will have no real face, but the key primordia have already begun to the key primordia have already begun to gather, and this early swellings ,depressions, gather, and this early swellings ,depressions, and thickenings are to undergo a series of and thickenings are to undergo a series of mergers and rearrangements that will mergers and rearrangements that will transfer them from cluster of separate masses transfer them from cluster of separate masses into a FACEinto a FACE

At fourth week of of IUL- At fourth week of of IUL- 1.migration of neural crest cell. 1.migration of neural crest cell. 2.formation of brachial arches2.formation of brachial arches

THE TWO PRINCIPAL SOURCES OF MESENCHYME IN HEAD ARE THE TWO PRINCIPAL SOURCES OF MESENCHYME IN HEAD ARE THE THE PARAXIAL MESODERMPARAXIAL MESODERM & & THE NEURAL CREST CELLS.THE NEURAL CREST CELLS.

CEPHALIC NEURAL CREST CELLS ARE PARTICULARILY IMPORTANT INCEPHALIC NEURAL CREST CELLS ARE PARTICULARILY IMPORTANT IN THE FORMATION OF THE FACIAL PART OF THE SKULL.THE FORMATION OF THE FACIAL PART OF THE SKULL.

THESE CELLS MIGRATE BOTH IN FRONT & BEHIND THE DEVELOPINGTHESE CELLS MIGRATE BOTH IN FRONT & BEHIND THE DEVELOPING EYE TO REACH THE PREDETERMINED SITES EYE TO REACH THE PREDETERMINED SITES FACIAL SWELLINGS.FACIAL SWELLINGS.

MIGRATION IS ASSITED BY HYALURONATE RICH FIBRONECTIN, MIGRATION IS ASSITED BY HYALURONATE RICH FIBRONECTIN, COLLAGEN, CHONDRITIN SULFATE & GLYCOSAMINOGLYCANS.COLLAGEN, CHONDRITIN SULFATE & GLYCOSAMINOGLYCANS.

THE DISTRIBUTION & CONCENTRAION OF THESE PRODUCTS VARIES THE DISTRIBUTION & CONCENTRAION OF THESE PRODUCTS VARIES ALONG THE MIGRATION ROUTE.ALONG THE MIGRATION ROUTE.

STOMODEUMSTOMODEUM -INVAGINATION OR DIMPLE IN THE -INVAGINATION OR DIMPLE IN THE

SURFACE ECTODERM.SURFACE ECTODERM. BUCCOPHARYNGEAL MEMBRANEBUCCOPHARYNGEAL MEMBRANE

RUPTURES RUPTURES

FOREGUT(PHARYNX)FOREGUT(PHARYNX)

AT 4AT 4THTH WEEK WEEK -SEGMENTATION OF FUTURE FACE , -SEGMENTATION OF FUTURE FACE ,

AND NECK REGION. AND NECK REGION.

PHARYNGEAL ARCHESPHARYNGEAL ARCHES PHARYNGEAL POUCHESPHARYNGEAL POUCHES PHARYNGEAL CLEFTSPHARYNGEAL CLEFTS

FIRST ARCH - MANDIBULAR ARCHFIRST ARCH - MANDIBULAR ARCH

BUD FOR MAXILLARY PROCESSBUD FOR MAXILLARY PROCESS

FACE AT 5TH WEEK IS AS THICK AS SHEET OF PAPER .

• 2 SMALL RAISED AREAS-NASAL PLACODES

• CENTRES DEEPENS TO FORM NASAL PITS

• BETWEEN NASAL PITS- MNP

• LATERALLY -LNP

MNP MERGES IN THE MIDLINE TO FORM THE PRIMORDIA FORMNP MERGES IN THE MIDLINE TO FORM THE PRIMORDIA FOR MIDDLE PART OF NOSEMIDDLE PART OF NOSE PHILTRUMPHILTRUM PREMAXILLAPREMAXILLA PRIMARY PALATEPRIMARY PALATE

LNP ENLARGES TO FORMLNP ENLARGES TO FORM ALAE OF NOSEALAE OF NOSE

LATERAL MERGING OF MAXILLARY AND LATERAL MERGING OF MAXILLARY AND MANDIBULAR PROCESS FORMS CHEEK.MANDIBULAR PROCESS FORMS CHEEK.

UPPER LIP

• MNP +MAXILLARY PROCESS• 3 STAGES• 1.CONTACT OF TWO EPITHELIAL SHEETS.• 2.FUSION OF EPITHELIUM INTO SINGLE

SHEET.• 3.DEGENERATION OF THIS SHEET,

FOLLOWED BY INVASION OF THE CONNECTIVE TISSUE OF THE LIP GROWING THROUGH IT.

PALATE

• FORMATION OF PRIMARY AND SECONDARY PALATE.

• ELEVATION OF PALATAL SHELVES.

• FUSION OF THE SHELVES

PALATOGENESIS5-12 WEEKS

6-9 WEEKS IS CRITICAL

PALATE

PRIMARY SECONDARY

FORMATION OF PALATE

• THE STOMODEAL CHABER DIVIDES INTO ORAL AND NASAL CAVITIES WHEN THE FRONTONASAL PROMINENCES DEVELOP HORIZONTAL EXTENSIONS INTO THE CHAMBER.

THESE EXTENSIONS FORM • CENTRAL PART OF UPPER LIP.• PRIMARY PALATE FROM FRONTONASAL PROCESS. • TWO LATERAL SHELVES FROM MAXILLARY PROCESS.

• TONGUE INTERVENSION

WEDGE SHAPED PALATAL SHELVES GROW DOWNWARD INTO FLOOR OF MOUTH.

• VERTICALLY ORIENTED

ELEVATION OF PALATAL SHELVES

• CRITICAL STEP.• 6-9 WEEKS. • CHANGE FROM VERTICAL POSITION FROM

BESIDES THE TONGUE TO HORIZONTAL POSITIONS OVERLYING THE TONGUE.

• INVOLVES MOVEMENT OF BOTH THE TONGUE AND PALATAL SHELVES.

• AS THE SHELVES ROLL OVER THE TONGUE,THE TONGUE MAY GLIDE ANTERIORLY TO OFFER LESS RESISTANCE.

• PALATAL SHELVES MEET FIRST IN ANTERIOR REGION WHERE THEY UNITE WITH PRIMARY PALATE AND NASAL SEPTUM.

REASON FOR ELEVATION OF SHELVES AND THEIR CONTROVERSY

• RELATIONSHIP BETWEEN INCREASED VENTRAL GROWTH OF MANDIBLE, DISPLACEMENT OF TONGUE, AND PALATAL ELEVATION NOT CLEAR.

• ROLE OF MUSCULAR ACTIVITY AND CERVICAL FLEXION PROPOSED.

• INTRINSIC MECHANISM BY WHICH PALATAL SHELVES BECOME REORIENTED.

• 3 BASIC FACTORS

• 1.CONTRACTILE ELEMENTS WITHIN THE SHELVES.• 2.CHANGES IN EXTRACELLULAR MATRIX. (INTRINSIC SHELF FO RCE). -GEL FIBRE NETWORK.

• 3.CHANGES IN EPITELIAL CELL ADHESIVITY AND TRACTION.

SHIFT IN CIRCULATION

• IMPORTANT SHIFT IN CIRCULATION IN THIS REGION DURING CRITICAL TIME PERIOD OF 7-8 WEEK.

• 6TH WEEK –STAPEDIAL ARTERY –ICA.• 7THWEEK –STAPEDIAL ARTERY SEVERES ITS CONTACT

WITH ICA.• SAME TIME ITS BRANCHES TO MAXIILLA AND

MANDIBLE GETS ATTACHED TO ECA.

ICA ECA

CHANGE IN BLOOD SPPLY OF FACE DURING 7TH WEEK

FUSION OF PALATAL SHELVES

• 9-10 WEEK.

• EPETHLIUM THICKENS AND CONTACTS.

• ROLE OF GLYCOPROTEINS AND DESMOSOMES • DEGENERATION OF EPITHELIUM.

• CONECTIVE TISSUE PENETRATION AND INTERMINGLING.

• ENTIRE PALATE DOES NOT FUSE AT SAME TIME, INTIAL CONTACT ,CENTRL REGION OF SECONDARY PALATE, THEN CLOSURE CONTINUES BOTH ANT. AND POSTERIORLY.

FUSION

OSSIFICATION CENTRE FOR

MAXILLA• PRIMARY CENTRE-• 7TH WEEK• AT TERMINATION OF INFRAORBITAL NERVE.

• SECONDARY CENTRE-• ZYGOMATIC.• ORBITONASAL• NASOPALATINE.• INTERMAXILLARY.

POST NATAL GROWTH

CAN BE EXPLAINED BY• SURFACE APPOSITION. • SUTURAL HYPOTHESIS• NASAL SEPTUM.• LACRIMAL SUTURE• MAXILLARY TUBEROSITY• KEY RIDGE • FUNCTIONAL MATRIX THEORY

SURFACE APPOSITION

APPOSITION

SURFACE APPOSITION OF MAXILLARY TUBEROSITY AREA

ZYGOMATIC REGION• POSTERIOR

SURFACE-DEPOSITORY.

• ANTERIOR-RESORPTIVE -POSTERIORLY.

• LATERAL SIDE-DEPOSITION

• MEDIAL RESORPTION-

LATERALLY

SURFACE APPOSITION IN ALVEOLAR SURFACE

PRIMARY DISPLACEMENT

SECONDARY DISPLACEMENT

SUTURAL THEORY

• STATES THAT THE DISPLACEMANT OF MAXILLARY COMPLEX IS DUE TO PRIMARY GROWTH AT CIRCUMMAXILLARY SUTURES.

• CENTRE OF PRIMARY GROWTH.

• DEMONSTRATED TO BE SITE OF SECONDARY ,COMPENSATORY BONE GROWTH PRIMARILY RESPONSIVE TO EXTRINSIC ENVIRONMENTAL FACTORS.

SUTURE SYSTEM

• THE MIDFACE IS CONNECTED TO NUEROCRANIUM BY A CIRCUMMAXILLARY SUTURE SYSTEM.

• SAGITTAL SUTURE STSTEM COMPRISES OF -MIDPALATAL -INTERMAXILLARY -INTERNASAL

NASAL SEPTUM HYPOTHESIS

• NATURE OF THE TISSUE.• EFFECT OF REMOVAL OF NASAL SEPTUM.

NATURE OF TISSUE

• HYALINE CARTILAGE

• CAPABLE OF TISSUE SEPERATING GROWTH.

• PART OF CARTILAGENOUS CRANIAL BASE.

ON REMOVAL• MIDFACIAL GROWTH IS DEFICIENT A-P AND

TO LESSER EXTENT,VERTICALLY.

• 30% DECREASE AT PREMAXILLO-MAXILLARY SUTURE.

• SLIGHT DECREASE IN GROWTH AT MAXILLO PALATAL SUTURE.

• IMPORTANT BUT NOT DETERMINING.

TWO MECHANISMS

• INTERSTITIAL CARTILAGINOUS GROWTH WITHIN THE NASAL SEPTUM PUSHES THE MIDFACE DOWNWARD AND FORWARD RELATIVE TO CRANIAL BASE WITH CIRCUMAXILLARY SUTURES FILLING IN.

(SCOTT,1953)

22NDND HYPOTHESIS IDENTIFIED HYPOTHESIS IDENTIFIED SEPTOPREMAXILLARY LIGAMENT.SEPTOPREMAXILLARY LIGAMENT.

THOUGHT TO PROVIDE A MEANS FOR THOUGHT TO PROVIDE A MEANS FOR THE GROWTH OF NASAL SEPTUM TO THE GROWTH OF NASAL SEPTUM TO BE TRANSLATED INTO A TRACTION, BE TRANSLATED INTO A TRACTION, OR A PULL, RATHER THAN PUSH.OR A PULL, RATHER THAN PUSH.

(LATHAM 1970)(LATHAM 1970)

FUNCTIONAL MATRIX HYPOTHESIS

• THE FUNCTIO NAL MATRIX HYPO THESIS EXPLICITLY CLAIMS THAT THE O RIG IN , G RO WTH AND MAINTAINENCE O F ALL SKELETAL TISSUE AND O RG ANS ARE ALWAYS SECO NDARY, CO MPENSATO RY AND O BLIG ATO RY RESPO NSE TO TEMPO RALLY AND O PERATIO NALLY PRIO R EVENTS O R PRO CESSES THAT O CCUR IN SPECIFICALLY RELATED NO NSKELETAL TISSUES , O RG ANS O R FUNCTIO NING SPACES.

(MO SS, 1 9 8 1 )

STATES THAT FACE IS NOT ONLY STATES THAT FACE IS NOT ONLY COMPRISED OF FUNCTIONAL COMPRISED OF FUNCTIONAL COMPONENTS, BUT IT IS ALSO COMPRISED COMPONENTS, BUT IT IS ALSO COMPRISED OF NUMBER OF FUNCTIONING SPACES – OF NUMBER OF FUNCTIONING SPACES – THE NASAL ,THE PHARYNGEAL, AND ORAL THE NASAL ,THE PHARYNGEAL, AND ORAL –WHICH TOGETHER FORM THE –WHICH TOGETHER FORM THE OROFACIAL OROFACIAL CAPSULAR MATRIX.CAPSULAR MATRIX.

““EPIGENIC” GOVERNING DETERMINANT .EPIGENIC” GOVERNING DETERMINANT .

SKELETAL UNIT FUNCTIONAL SKELETAL UNIT FUNCTIONAL . . MATRIX MATRIX

BASAL BODY INFRAORBITAL BASAL BODY INFRAORBITAL NERVE NERVE

ORBITAL UNIT EYEBALLORBITAL UNIT EYEBALL

NASAL UNIT SEPTAL CARTILAGENASAL UNIT SEPTAL CARTILAGE

ALVEOLAR UNIT TEETHALVEOLAR UNIT TEETH

MAXILLARY TUBEROSITY

• DEPOSITION ALONG THE POSTERIOR MARGIN.

• ENDOSTEAL SIDE OF CORTEX-RESORPTIVE.

• POSTERIOR AND LATERAL MOVEMENT.

KEY RIDGE

• VERTICAL CREST JUST BELOW MALAR PROTUBERANCE.

• FIXED REFERANCE POINT.

V PRINCIPAL OF ENLOWS AND BANG

Growth in height verticalGrowth in height vertical

Growth in width transverseGrowth in width transverse

Growth in length A - PGrowth in length A - P

WIDTH

• GROWTH OF MIDPALATINE SUTURE.

• REMODELLING OF LATERAL SURFACE OF ALVEOLAR PROCESS.

• MUTUAL TRANSVERSE ROTATION GIVES PALATE “U” SHAPE.

LENGTH

Maxillary tuberosity

Palato -

maxillary suture

primary secondary

displacement

POST NATAL

• AT BIRTH HARD PALATE- LENGTH = WIDTH• 1-2 YEAR -EXTENSIVE REMODELLING DESCENT OF PALATE ENLARGEMENT OF NASAL CAVITY MIDPALATINE GROWTH CEASES BUT NO SYNOSTOSIS.

MIXED DENTION• GROWTH IN WIDTH OF ARCH ANTERIOR TO

1ST MOLAR CEASES BY 5-6 YEARS.• INTERCANINE WIDTH IS COMPLETED BY 12

YEARS IN FEMALES AND 18 YEARS IN MALES.• MIDPALATINE SUTURE STARTS CLOSING

BY 9-10 YEARS.• THERFORE RME CAN BE BEST DONE AT 9-14 YEARS.

7TH YEAR –A BENCHMARK

• GROWTH OF CNS, BRAIN AND EYE ESSENTIALLY COMPLETED.

• SPHENOETHMOIDAL SYNCHONDROSES FUSES AT ABOUT THE TIME ESTABLISHING A RELATINELY STABLE ANTERIOR CRANIAL BASE.

• NASAL CAPSULE OSSIFIES.

DEVELOPMENTAL DISTURBANCES AFFECTING MAXILLA

• CLEFT PALATE.• MICRO G NATHIA.• MACRO G NATHIA.• TREACHER CO LLINS SYNDRO ME.• CLEIDO CRANIAL DYSO STO SIS.• CRO UZO NS SYNDRO ME.• APERT SYNDRO ME.• ACHO NDRO PLASIA.

CLEFT LIP AND PALATE

• DEVELOPS DUE TO NON FUSION OF• CLEFT LIP -FNP +MAXILLARY PROCESS • CLP -MNP+MAXILLARY PROCESS • MIDLINE CLEFT OF UPPER LIP -FNP (LOWEST PART) OBLIQUE FACIAL CLEFT -MAX. PROCESS + LNPLATERAL FACIAL CLEFT -UNILATERAL NON FUSION OF MAX+MAND PROCESS

CLEFT LIP AND CLEFT PALATE

• CLEFT PALATE DUE TO NON FUSION OF LATERAL PALATINE PROCESS.

• MACROSTOMIA –MAXILLARY . +MANDIBULAR PROCESS

• MICROSTOMIA – TOO MUCH FUSION OF MAXILLARY + MANDIBULAR PROCESS

TREACHER COLLINS SYNDROME

• ALSO CALLED AS MANDIBULOFACIAL DYSOSTOSIS.

• DUE TO UNDERDEVELOPMENT OF 1ST ARCH, MAX. MESODERM AT AND AFTER 2 MTS OF I.U LIFE NOT DEVELOPED.

• HYPOPLASTIC MALAR AND MANDIBLE BONE.

• MACROSTOMIA, HIGH ARCHED PALATE.

ACHONDROPLASIA

• RETARDED MAXILLARY GROWTH.

• ENLARGED CALVARIA.

• FRONTAL BOSSING.

• DISTURBED ENDOCHONDRAL BONE FORMATION.

• SHORT UPPER FACIAL HEIGHT.

CLEIDOCRANIAL DYSOSTOSIS

• OPEN FONTANELLES

• SUNKEN SAGITTAL SUTURE

• UNDERDEVLOPED MAXILLA

• NARROW PALATE

APERT SYNDROME: • IS A SINGLE GENE DISORDER, CHARACTERIZED BY

PREMATURE FUSION OF CRANIAL SUTURES,• BIZARRE CRANIOFACIAL APPEARANCE,• HIGHLY ARCHED PALATE, • SYNDACTYLY (FUSION OF DIGITS)• CONGENITAL HEART DEFECTS

CROUZAN SYNDROME

• SAME AS APERT SYNDROME BUT WITHOUT SYNDACTYLY

• TRIANGULAR FRONTAL DEFECT.

CONCLUSION

JUST AS THE CLINICIAN NEEDS THE MEDICAL HISTORY TO

MAKE A LOGICAL DIAGNOSIS, SO TOO THE GROWTH AND

DEVELOPMENT OF FACE IS ESSENTIAL FOR A LOGICAL

EXPLANATION OF ANY STRUCTURAL AND FUNCTIONAL

IMBALANCES IF IT DO OCCURS.

REFERANCES

• ESSENTIALS OF FACIAL GROWTH –DONALD H . ENLOW

•

• CRANIOFACIAL DEVELOPMENT - SPERBER

• HANDBOOK OF ORTHODONTICS - ROBERT E.

• MOYERS

• INTRODUCTION TO CRANIOFACIAL BIOLOGY- DAVID S.CARLSON .

• . -SALZMAN

• ORAL PATHOLOGY -SHAFERS

• GRAYS ANATOMY

• -MCDONALD

• HUMAN ANATOMY COLOUR ATLAS –MCMINN AND HUTCHINGS