Development of Face and Anomalies

8/12/2019 Development of Face and Anomalies

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DEVELOPMENT OF FACE AND

ANOMALIES

PRESENTED BY

DR. GOPI



Contents

Introduction

Embryology & Prenatal growth

Post natal growth Anomalies

Conclusion



PRENATAL GROWTH The development of head depends on

Prosencephalic centre

Rhombencephalic centre

Prosencephalic centre -migrates from the primitivestreak

Induces Visual and inner ear apparatus

Upper 1/3 of face

Caudal Rhombencephalic centre

Induces middle and lower 1/3 of face and middleand ext ears.



Formation of the Human Face 1st characterized by an invagination in the

ectoderm below the forebrain. As it deepens,itforms an outline of the oral cavity.

Prechordal Plate

demarcates the site of the stomodeum( 14th day)

endodermal thickening contributes to- oropharyngealmembrane.

Ectoderm – forms mucosa of mouth.

Endoderm – forms mucosa of pharynx.

Mesoderm – does not intervene.



Face develops from 5 prominences surrounding the

stomodeum

Frontonasal

Two maxillary processes 1st Arch Derivatives

Two mandibular processes

All prominences and arches arise from neural crest

cells-caudal stream



Frontonasal prominence

4th week iu

Develops from Cranial stream of neural crest cells

proliferate downwards to form FN process.

It surrounds the developing forebrain

Nasal placodes arises inferolaterally



The frontal portion of the prominence

b/w the eyes forms the Forehead.



At the infero-lateral corners, thickened

ectodermal nasal placodes arise



These placodes induced by the underlying

olfactory nerves

Invaginate

Demarcate the medial andlateral nasal prominences.

Nasal pits

Precursors to Anterior nares



Post. Merging of Medial nasal processes

Median primary palate

Premaxilla

Future site of 4 upper incisors



Midline merging of the paired

mandibular prominences

Lower jaw + Lower lip

-- First to get definitely established.



Lateral merging of maxillary and

mandibular prominences.

Commisures of mouth



All the regions of the face grow in proportion toeach other and equally.

i.e. any malproportioning at this time may forma basis for craniofacial defects.



Maxilla Acc to Jacobson it develops from a condensation of embryonic

mesenchyme within the maxillary process of the mandibulararch

1 ossification centre-7

th

wk iu- at termination of infra orbitalnerve just above the canine tooth dental lamina.

2 ossification centers – zygomatic

orbitonasalnasopalatine

intermaxillary

G h f ill d d l



Growth of maxilla depends upon severalfunctional matrices that act on different areas andthus allowing for its subdivision into skeletal units.

a) Basal body

b) Orbital unit

c) Nasal unit

d) Alveolar unit

e) Pneumatic unit



The complexity of action of forces results in differenteffects on different sutures

TZ suture - A-P horizontal growth - brain and s-osynchondrosis.

F-M, F-Z, F-N, E-M,F-E suture - vertical growth - eyeballand nasal septum expansion

N-M suture-A-P growth-nasal septum



Eye balls Grow rapidly following neural pattern of growth and

contributing to rapid widening of the face.

half of postnatal growth- 2 years

adult dimensions- 7 years.



Nasal Cavity and Septum A septomaxillary ligament arises from nasal septum

and inserts into Anterior nasal spine. It transmitsseptal growth ‘pull’ on the maxilla.

Facial growth is directed downwards and forwards by

the septal cartilage



Palate Derived from

two lateral max palatal shelves primary palate of F-N prominence

initially vertically oriented

8th week iu transformation from vertical tohorizontal

considerable sex difference in timing. Earlier inmale than female embryos.

Factors influencing change of orientation



Factors influencing change of orientation

Biochemical transformations in physical consistency ofconnective tissue matrices.

Variation in vasculature and blood flow

Sudden increase in tissue turnover.

Rapid mitotic activity

Intrinsic shelf force

Muscular movements

Withdrawl of face from heart prominence



Fusion occurs initially - anteriorly in hard palate,combination of degenerating epithelial cells, and asurface coat accumulation of glycoproteins and

desmosomes facilitates epithelial adherence



The fusion initially produces a flat, unarched roof.

Junction of components -incisive papilla.

Line of fusion- mid Palatine suture.

This fusion seam is minimized in soft palate byinvasion of extra territorial mesenchyme.



Ossification - 8th week iu

Anteriorly-primary ossification centre of maxilla Posteriorly- primary ossification centre of palatine

bones.

Mid palatal suture 10 1/2 weeks-fibrous layer in the midline.

infancy - Y shape in coronal section

childhood - T shape

adolescence - Interdigitated



Tongue :

Ant 2/3rd :-- Median triangular elevation in the floor of

the primitive pharynx ant. to foramen caecum termedas Median tongue bed.

( Tuberculum Impar)

-- Mesenchyme of the 1st arch give rise to 2distal tongue beds on either side of median tongue

bed.



Median and distal tongue beds rapidly

increase in size and fuse together to form theant.2/3rd of the tongue.

2 elevations copula and the hypobranchialeminence form the posterior 1/3rd of the

tongue.



External ear :

1ST Brachial groove-- External acoustic meatus



• Auricle derived from

the auricular hillocks

i.e. the mesoderm of

the 1st and 2nd

Branchial arches.



PRENATAL GROWTH

OF MANDIBLE

During 3rd & 8th week of development, a period

known as the embryonic period, each of the 3germ layers (endoderm, ectoderm &mesoderm) give rise to a number of specifictissues & organs.



Meckel’s cartilage

Inferior Alveolar Nerve

Center of ossification Canal for the nerve

Compartments for tooth germs

Fibro cellular capsule – Sphenomandibular ligament



FURTHER DEVELOPMENT Secondary cartilages (Three)

Condylar cartilage

Coronoid cartilage Symphysial cartilage



DEVELOPMENT OF TMJ Formation of Articular disc and Joint cavity

Formation of Condyle

Growth of the Condyle Formation of Joint capsule



POSTNATAL GROWTH General Methods of Growth :

Remodelling.

Displacement

Relocation



Remodeling is a process of reshaping and resizing agrowing bone as it is relocated to new levels.

Relocation- while parts of bone are moved; itmaintains the form of the whole bone and causes its

enlargement.



Displacement – the whole bone is carried by amechanical force

Site -Articular contacts

1 displacement –the physical carry takes place inconjunction with the bones own enlargement

vectors oriented–posteriorly

and superiorly

bone displaced – anteriorly and inferiorly

2 displacement - movement of bone and soft tissues



2 displacement movement of bone and soft tissuesnot directly related to its enlargement.

Temporal lobe of cerebrum

Middle cranial fossa

Displace nasomaxillary complex downwards andforwards

i di l



Primary movement-displacement or

remodelling?

Displacement is presently believed by manyresearchers to be the primary change with rate and

direction of bone growth representing a secondary(transformative) response

It is also believed that both may be responding tocommon signals that separately but simultaneously

activate both to operate in unison



Rotation –2 types

Remodelling rotation

Displacement rotation.

Nasomaxillary complex- displacement rotation ineither a clock or counter clock wise direction

depending on growth activities of basicranium andsutural system.

Palate- remodeling rotation occurs in a counter

direction.



POSTNATAL GROWTH

OF MANDIBLE

Of all the facial bones mandibleundergoes the largest amount of growth

postnatally.



THE SYMPHYSIS By the 1st year the

symphyseal cartilage isreplaced by bone.



THE RAMUS The principle growth

vectors are in posterior &superior direction



FUNCTIONS OF REMODELING

OF RAMUS To accommodate & provide an attachment base for the

increasing mass of masticatory muscles.

To accommodate the enlarged breadth of the pharyngeal

space. To accommodate the vertical lengthening of the

nasomaxillary part of the growing face.

To facilitate the lengthening of the corpus which in turn

accommodate the erupting molars.



RAMUS UPRIGHTING Greater amounts of bone

deposition takes inferiorlythan superiorly on the

posterior border of ramus. Correspondingly greater

amounts of resorption onant. Border takes places

inferiorly than superiorlyresulting in aREMODELLINGROTATION



CORONOID PROCESS



MANDIBULAR CONDYLE



CHIN In infancy chin is under developed.

As age advances the growth of chin becomes

significant Males are seen to have prominent chin compared to

females.

The prominence is accentuated by bone resorption in

the alveolar region below it, creating a concavity



THE ALVEOLAR PROCESS It develops in response to the presence of tooth buds .

Its formation is controlled by dental eruption & it

resorbs where teeth are exfoliated / extracted. When corpus growth is over, vertical alveolar growth

persists as the occlusal surfaces wear & the occlusal

height is maintained

Adaptive remodelling of alveolar process makesorthodontc tooth movement possible.



ANOMALIES OF FACE Congenital defects:

Teratogens

Infection –German Measles – Cleft Palate X-Irradiation – Cleft Palate

Drugs –Tetracycline – Discoloration of teeth

Nutrition – Vitamin deficiency- Tested

Hormones – Cortisone- Cleft Palate in Mice



CLEFT LIP AND PALATE Unilateral, bilateral cleft lip

Oblique facial cleft and cleft lip

Median cleft lip and nasal defect

Median mandibular cleft

Unilateral microstomia



CLEFT PALATE More in females than males

Tongue obstruction

Small palatal shelves Failure of epithelial breakdown

Failure of mesodermal penetration

Post fusion rupture

Cleft palate and Cleft lip

Cleft palate



Cleft palate-

Cleft lip and palate



BIFID UVULA Mildest form of cleft palate



TREACHER COLLIN SYNDROME

Anti mongoloid slope

Hypoplasia of maxilla

and zygoma Malocclusion

Cleft palate



DOWNS SYNDROME

Trisomicchromosome

Typical mongoloidappearance

Mid face ishypoplastic

Cleft lip and cleftpalate are seen



ASCHERS SYNDROME

Sagging eyelids

Nontoxic thyroid

enlargement Double lip is seen



PATAU’S SYNDROME

Cleft lip

Cleft palate

Micrognathia



GORLIN’S SYNDROME

Odontogenickeratocyst in

mandible Multiple basal cell

neavi

Cleft lip and/or cleft

palate is seen

Bifid ribs are seen



TONGUE TIE

Ankyloglossia

Interferes with

speech Difficult to cleanse

the food away

Lingually placedcentrals



ELLIS-VAN CREVELED SYNDROME

Chondro ectodermaldysplasia

Dwarfism

Incisiors are missing

Hypoplastic teeth

Multiple freanae arepresent

PIERRE ROBINSON



PIERRE ROBINSON

SYNDROME(BIRD FACE)

Severe micrognathia

Cleft palate

Periodic dyspnoea Congenital cardiac

annomalies

Mentally handicap glossoptosis

CONCLUSION



CONCLUSION

Facial growth is a process requiringintimate morphogenicinterrelationships among all of it’s

component growing, changing andfunctioning soft and hard tissue parts.No part is developmentally

independent and self contained.

Development of Face and Anomalies

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