development of face & developmental anomalies

PRESENTED BY

ABHITOSH DEBATA

A SEMINAR ON

DEVELOPMENT OF FACE

INTRODUCTION DEFINITIONEVENTS OF DEVELOPMENT EMBRYOLOGICAL DEVELOPMENT DEVELOPMENT OF BRANCHIAL (ARCHES ,

POUCHES AND CLEFTS) DEVELOPMENT OF FACE DEVELOPMENTAL ANOMALIES OF FACE CONCLUSIONREFERENCES

CONTENTS

Anatomical structures are more diverse in the mouth than in any other region. Human development is a continuous process and does not stop at birth. An individual spends about 9 months/ 38 weeks/266 days or nearly 383040minutes of his life in his mother’s womb.

The human face begins to form during the 4th week of embryonic development. By the 6th week the external face is completed. Between the 6th and 8th weeks the development of the palate subdivides nasal and oral cavities. This development continues into the 12th week with completion of the soft palate.

INTRODUCTION

Embryology:Science of the origin & development of the organism from fertilization of the ovum to the end of the eighth week.Development:Development refers to all the naturally occurring unidirectional changes in the life of an individual from its existence as a single cell to its elloboration as a multifunctional unit terminating in death. Thus it encompasses the normal sequential events between fertilization and death.

DEFINITION

Third week Development of earFormation of Stomatodaeum.

Fourth weekFormation of Fronto-nasal process, maxillary and mandibular process.Development of cranial base.Formation of pharyngeal arches.Development of tongue.

Fifth week Formation of Nasal placode, Medial and lateral nasal process.Development of mandible.

Sixth week Development of Nasal cavity.Development of Parotid and Submandibular salivary glands

Seventh week Formation of pre-maxilla

Eight week Formation of definitive palate.Development of Sublingual salivary glands

Tenth week Development of TMJDevelopment of Maxillary sinus.

Twelth week Development of Ethmoidal, Frontal and Sphenoidal sinuses.

• Pre-implantation period or Period of ovum(1-2weeks)• Embryonic period( 3rd to 8th week)• Fetal period( 9th week till birth)

EARLY EMBRYONIC DEVELOPMENT

- The period of one week from fertilization to implantation of the fertilized egg is called the pre-implantation period.

PRE-IMPLANTATION PERIOD

1ST WEEK OF DEVELOPMENT

-The period of embryo is divided into 3 stages -PRESOMITE stage – an embryo in any stage of development before the appearance of the first pair of somites (primitive segments/metameres), which in humans usually occurs around 19 to 21 days after fertilization of the ovum.-SOMITE stage - an embryo in any stage of development between the formation of the first and the last pairs of somites, which in humans occurs in the third and fourth weeks after fertilization of the ovum. -POSTSOMITE stage –The developing embryo then gets attached to the uterine endometrium, this is called Implantation.After Implantation the endometrium is called Decidua.The placenta is formed partly by embryonic structures and partly from the decidua. 

EMBRYONIC PERIOD

-Fertilization of ovum takes place in the ampulla of the uterine tube.When there are 16 cells the ovum is called a morula.

- - The cells of the inner cell mass rearrange to form the embryonic disc having two germ cells namely ECTODERM & ENDODERM and the third layer is formed between the 2 layers i.e known as MESODERM.

FORMATION OF GERM LAYERS

PRIMITIVE STREAK

NOTOCHORD FORMATION

- In the Fetal period all major structures are already formed in the fetus, but they continue to grow and develop.

The last 7 months of fetal life are devoted to very rapid growth and repositioning of body components, with little further organogenesis or tissue differentiation. By 3rd month sex of fetus is known. In the 4 months human face is seen and in the Last 2 months of fetal life fat is deposited subcutaneously

FETAL PERIOD

- Pharyngeal arches are rod like thickenings of mesoderm present in the wall of the foregut.

- At first there are 6 arches. The 5th arch disappears and then only 5 arches remain.

- In the interval between any two arches the endoderm (lining of the pharynx) is pushed outwards to form a series of pouches. These are called Pharyngeal pouches.

DEVELOPMENT OF PHARYNGEAL ARCHES

- Cartilage component :

Adapt to form Bony, Cartilagenous or Ligamentous structures- Muscle component :

Give rise to special visceral muscles composed of striated muscle fibers.

- Vascular component :

Provides necessary blood supply

- Nerve component :

Enters mesoderm of the branchial arches and initiates muscle development of mesoderm.

Components of Pharyngeal Arches

Cartilagenous components of various arches

MUSCULAR COMPONENTS OF PHARYNGEAL ARCHES

- Precursor of both the jaws: Maxilla + Mandible- Initially gives rise to a large mandibular prominence.- Gives rise to a small maxillary prominence which extends cranioventrally.

1ST PHARYNGEAL ARCH(Mandibular Arch)

Cartilage : MECKEL’S CARTILAGE -Arises in 41st – 45th Day of intrauterine life. -It provides a template for subsequent development of the mandible.

Derivatives of Meckel’s cartilage- -Mental Ossicle -Head and neck of Malleus. -Short crus of the Incus. -Anterior Ligament of the Malleus. -Sphenomandibular Ligament

COMPONENTS OF 1ST BRANCHIAL ARCH:

Musculature derived from 1st arch-

-Muscles of Mastication.

-Mylohyoid Muscle.

-Ant. Belly of Digastric.

-Tensor Tympani.

-Tensor Veli Palatini Muscles.

3. Arterial Component:

-Part of Maxillary and External Carotid Artery.

4. Nerve components: -- Mandibular division of Trigeminal Nerve ( Vth Cranial Nerve) -- Sensory component supplies : Mandible and covering mucosa. : Mandibular teeth including Gingiva. : Mucosa of ant. 2/3 of Tongue. : Floor of the mouth. : Skin of the lower third of Face

COMPONENTS: 1. Cartilage : Reichert’s Cartilage (45th – 48th I.U) - Greater part of the third ear ossicle. - Stapes . - Styloid process of the temporal bone. - Stylohyoid ligament. - Lesser horn and - Cranial part - Body of Hyoid. - Segments of the facial canal.

2ND PHARYNGEAL ARCH(HYOID ARCH)

2. Muscles : - Stapedius - Stylohyoid - Post. Belly of Digastric. - Muscles of facial expression. - Levator Veli Palatini.

3. Nerve : - Facial nerve. - Special sensory component - Chorda tympani nerve (Ant 2/3rd of Tongue)4. Artery : - Stapedial artery - Transient i.e. disappears during fetal life.

COMPONENTS:1.MUSCLES – STYLOPHAYNGEOUS MUSCLE2.NERVE – GLOSSOPHAYNGEAL NERVE3.ARTERY-PROXIMAL 1/3RD OF INTERNAL CAROTID ARTERY.SMALL CONTRIBUTION OF COMMON CAROTID ARTERY.4. SKELETON – Greater horn Lower body of hyoid

3RD PHARYNGEAL ARCH

COMPONENTS:

1. MUSCLES-Constrictor muscles of pharynx.2. NERVE –Superior laryngeal nerve3. ARTERY –Arch of aortaProximal part of subclavian4. SKELETON –Thyroid cartilage

4TH PHARYNGEAL ARCH

COMPONENTS:1.MUSCLES- Intrinsic muscles of larynx2.NERVE- Recurrent laryngeal nerve3.ARTERY- Pulmonary artery Ductus arteriosum4.SKELETON- Cricoid Arytenoid

6TH PHARYNGEAL ARCH

1st pharyngeal pouch –• It forms a star like diverticulum “tubotympanic recess”, which comes in contact with the epithelial living of the 1st pharyngeal cleft, the future external auditory meatus.• The distal portion of the diverticulum widens into primitive middle ear cavity and the proximal part remains narrow forming the eustachian tube.• The lining of tympanic cavity later aids in formation of the tympanic membrane or eardrum.

PHARYNGEAL POUCHES

2nd pharyngeal pouch:

•The epithelium of the ventral part of this pouch contributes to the formation of tonsil.

•Dorsal part takes part information of tubo tympanic recess.

3rd pharyngeal pouch : •It has dorsal and ventral wings. •During 5th week, epithelium of dorsal wing of the 3rd pouch differentiates into inferior parathyroid gland, while ventral wing forms the thymus. •Thymus migrates in a caudal and medial direction pulling inferior parathyroid with it, which finally rest on the dorsal surface of thyroid gland.

4th pharyngeal pouch:•Epithelium of dorsal wing forms the superior parathyroid gland.

5th pharyngeal pouch:•Considered as a part of 4th pouch. It gives rise to ultimobronchial body, which later forms parafollicular or “C” cells of thyroid gland. •These cells secrete calcitonin, hormone involved in calcium regulation.

PHARYNGEAL CLEFTS & POUCHES

• 5 week embryo is characterized by 4 pharyngeal clefts.• Dorsal part of 1st cleft penetrates the underlying mesenchyme and gives rise to the external auditory meatus.• The epithelial lining at the bottom of the meatus participates in formation of the eardrum. • Active proliferation of mesenchymal tissue in the 2nd arch causes it to overlap the 3rd and 4th clefts (arches). • Finally it merges with the epicardial ridge in the lower part of neck and the 2nd, 3rd and 4th clefts lose their contact with outside. • These clefts form a cavity lined with ectodermal epithelium, the “cervical sinus”, but with further development this sinus disappears.

PHAYNGEAL CLEFTS

KEY POINTS:-• Face develops from 3 prominences that surround the stomatodeum-it is a depression bounded cranially by a bulging produced by the brain and caudally by a bulging produced by the pericardial cavity. 1.Frontonasal process 2.Right and Left mandibular arch•The mandibular arch divides into a maxillary process and a mandibular process.•The right and the left mandibular arches meet in the midline and fuse. They form the upper and lower lips.

DEVELOPMENT OF FACE

• The cheek is formed by the fusion of posterior part of maxillary and mandibular process.• The nose is derived from the frontonasal process.• The nasal cavity is formed by enlargement of the nasal pits.• Paranasal sinuses appear as outgrowths from the nasal cavity.• The palate is formed by fusion of 3 components i.e right and left palatal processes and the primitive palate.• The oral cavity is derived party from the stomatodaeum(ectoderm) and partly from the foregut(endoderm).

• The teeth are formed in relation to the dental lamina. An enlargement of dental lamina for each tooth is formed which is called the enamel organ. Ameloblasts form the enamel, odontoblasts form the dentine and the mesenchyme that invaginates into enamel organ forms the pulp.• The ant. 2/3rd of the tongue is formed from the lingual swellings and the tuberculum impar.• The post.1/3rd of the tongue is formed by cranial part of hypobranchial eminence.• The salivary glands develop as outgrowths of buccal epithelium.• The palatine tonsil develops in relation to 2nd pharyngeal pouch.

• The pharynx is derived from the foregut.• Muscles of face develop from 2nd branchial arch and are supplied by facial nerve.• Eyes develop from three sources:Neuroectoderm of the forebrain - retina,optic n.Surface ectoderm of the head - lensMesoderm between these layers – eye muscle and vascular tissues.• External ear develops from Ext. ocoustic meatus, middle ear develops from tubotympanic recess that is derived from 1st pouch and internal ear is derived from otic placode which is a thickening of surface ectoderm.

- The mandibular process of two sides grow towards each other and fuse in the midline.

- The fused mandibular process give rise to lower lip & to lower jaw.

DEVELOPMENT OF LOWER LIP

•Each mandibular process grows medially and fuses first with the lateral nasal process and then with medial nasal process.•The medial and lateral nasal processes fuse with each other n the nasal pits(ext.nares) are cut off from stomatodaeum.•The mesodermal basis of the lateral part of the lip is formed from the maxillary process and the overlying skin is derived from the ectoderm covering this process. •The mesodermal basis of the median part of lip (philtrum) is formed from frontonasal process.

•The skin of the entire upper lip is innervated by maxillary nerves.•The muscles of the face along with the lips are derived from mesoderm of second bronchial arch, are supplied by the facial nerve.

DEVELOPMENT OF UPPER LIP

• After the formation of the upper lip and lower lips the stomatodaeum becomes broader.• In its lateral part it is bounded by the maxillary process from above and mandibular process from below.• Progressive fusion of both the processes form the cheek.

DEVELOPMENT OF CHEEK

The nose is a complex of contributions from: • Frontal prominence - The bridge. • Medial nasal prominence - Median ridge and tip • Lateral nasal prominence - The alae • The cartilage of nasal capsule - the septum and nasal conchae.As the nose becomes prominent, the external nares open up downwards instead of forwards.

DEVELOPMENT OF NOSE

• The nasal cavities are formed by extension of the nasal pits. These pits are at first in open communication with the stomatodeum. Soon the medial and lateral nasal processes fuse, and form a partition between the pit and the stomatodeum. This is the primitive palate and is derived from the frontonasal process.• A dorsal orifice that opens into the stomatodeum- Primitive posterior nares. • The 2 nasal sacs enlarges and bring them closer together. • The frontonasal process becomes narrower.

DEVELOPMENT OF NASAL CAVITY

• The nasal cavities are separated from the mouth by the development of palate. The narrowing of the fronto-nasal process and the enlargement of nasal cavities brings them closer together. • The intervening tissues becomes much thinned to form the nasal septum.• The nasal pits now deepen to form the nasal sacs which expand both dorsally and caudally. The nasal sac has a ventral orifice that opens on the face is called the Anterior nares.

• Paranasal sinuses develop during late fetal life. • They form as outgrowths or diverticula of the walls of the nasal cavities and become air filled extensions of the nasal cavities in the adjacent bone.- Frontal – 3 to 4 months of I.U- Ethmoidal – 4 months of I.U- Maxillary – Develops at 10 weeks of I.U - Sphenoidal – 4 months of I.U

DEVELOPMENT OF PARANASAL SINUSES

• Ear consists of 3 anatomical parts:- Internal ear- Middle ear- External ear-External ear: External acoustic meatus:-Develops by deepening of the dorsal end of the 1st pharyngeal groove.• Pinna or Auricle:Six mesenchymal hillocks – Auricular hillocks develop from the 1st and 2nd pharyngeal arch.

DEVELOPMENT OF EAR

-Middle ear: Develops from the tubotympanic recess i.e. derived from the 1st pharyngeal pouch.

Tympanic cavity- Distal portion of the tubotympanic recess expands.Tympanic membrane: - Ectodermal lining from -1ST pharyngeal groove -Mesodermal lining from 1st and 2nd arch-Endodermal lining from tubotympanic recess

Ear ossicles:• 1st bone to attain ultimate size.

• Maleus and Incus develop from the 1st arch.

• Stapes develop from 2nd arch.

• Ossification begins in the 16th week and continues up to the 25th week

-INTERNAL EAR: • OTIC PLACODE

• Eyes develop from three sources:Neuroectoderm of the forebrain - retina, optic nerve.Surface ectoderm of the head- lensMesoderm between these layers - eye muscle and vascular tissues• 1st indication of eye formation is optic sulcus which is formed in the 4th week.

DEVELOPMENT OF EYE

- Tongue develops in relation to P.A in floor of developing mouth. - The medial most part of M.A proliferate to form Lingual swellings.- They are partially separated from each other by another swelling in midline called Tuberculum Impar.- Immediately behind Tuberculum Impar the epithelium proliferates to form a downgrowth from (thyroglossal duct) which thyroid gland develops. This site is marked by Foramen Caecum.- Hypobranchial eminence- midline swelling in relation to medial ends of 2nd, 3rd, & 4th arch. It has a cranial part called Copula (2nd, 3rd ), & caudal part ( 4th) forming epiglottis.

DEVELOPMENT OF TONGUE

- Anterior two-thirds of tongue forms by fusion of – 2 lingual swellings & Tuberculum impar- It is derived from Mandibular arch so supplied by lingual nerve, branch of Mandibular nerve which is post- trematic nerve of the 1st arch & chorda- tympani which is pretrmatic nerve of the arch.- Posterior one-thirds is formed from cranial part of H.E (copula) - The 2nd arch mesoderm buries below the surface, 3rd arch mesoderm grows over it to fuse with mesoderm of 1st arch.- Thus it is formed by 3rd arch mesoderm.

Supplied by glossopharyngeal nerve, of 3rd arch.- The posterior most part is formed from 4th arch, so it is supplied by superior laryngeal nerve of 4th arch.- Musculature is derived from occipital myotomes, supplied by hypoglossal nerve.

• Begins at 6th week- for primary palate • From each Max. P, a plate like shelf grows medially, this is called Palatine process. • Palate forms from 3 components fusing with each other--1) 2 Palatal processes, fuse in midline beginning from anterior to posterior 2) Primitive palate from FNP, each palatal process fuses with posterior margin of P.P• The medial edge of P.P fuse with free lower edge of nasal septum thus separating 2 nasal cavities from each other & from mouth.• At later stage mesoderm in palate undergoes intramembranous ossification to form hard palate. Ossification does not extend into posterior most portion which remains as Soft palate.• The part of palate derived from FNP is Premaxilla which carries 4 incisors.

DEVELOPMENT OF PALATE

• The maxilla develops from a centre of ossification in the mesenchyme of the 1st arch. The centre is in the maxillary process. No arch cartilage or primary cartilage exists in the maxillary process. • Centre of ossification appears in the angle between the division of the nerve, where the anterosuperior dental nerve is given off from the infra orbital nerve. From this centre bone formation spreads backward below the orbit towards the developing zygoma and forward towards the future incisor region.

DEVELOPMENT OF MAXILLA

• Ossification also spreads upward from this forward extension to form the frontal process. Ossification also spreads into the palatine process to form the hard palate. A secondary cartilage, a zygomatic or malar cartilage appears in the developing zygomatic process and for a short time adds considerably to the development of the maxilla.

- On lateral aspect of Meckel’s cartilage (1st arch cartilage) during 6th week of embryonic development, a codensation of mesenchyme occurs in the angle formed by division of Inferior Alveolar Nerve and its incisive and mental branches

- At 7th week ,intra membraneous ossification begins in this condensation forming the 1st bone of the mandible. From this centre of ossification, bone formation spreads rapidly, anteriorly to the midline and backwards towards the point where the mandibular nerve divides into lingual and IAN branches.

DEVELOPMENT OF MANDIBLE

- Ramus of mandible develops by a rapid spread of ossification backwards into mesenchyme of 1st arch, diverging away from Meckel’s cartilage. The point of divergence, is marked by lingula in adult mandible, where Inf.Alveolar Nerve enters body of mandible.- By 10th week, rudimentary mandible is formed entirely by membraneous ossification with no direct involvement of Meckel’s cartilage.- Further growth is influenced by secondary (growth) cartilage and development of muscular attachments. The cartilages one condylar, coronoid and symphyseal cartilages.

MECKEL’S CARTILAGE:-- Dorsal end ossifies to form malleus & incus - Its parts then transform into sphenomandibular ligament & ant. Malleolar ligament- Ventral end forms accessory endochondral ossicles- Then between 10th -14th weeks, secondary accessory cartilages appear to form the head of condyle, part of coronoid process and mental protruberance. By 24th week it disappears after conception.

Craniofacial voluntary muscles develop from somitomeres and somites of the occipital and nostral cervical regions.Myomeres of the somitomeres and myotomes of somites form primitive muscles cells called myoblasts.Myoblasts divide and fuse to form myotubes. Myotubes become myocytes (muscle fibres).Craniofacial muscles are derived segmentally from 7 somitomeres - 7 nostral somites ,4 ocular extrinsic muscles(superior , medial , inferior rectus and inferior oblique) derived from 1st two somitomores supplied by Oculomotor.Superior oblique ocular muscle- 3rd somitomere -Trochlear N (4th CN).

DEVELOPMENT OF MUSCLES OF FACE

Lateral r rectus- 5th somitomere (Abducent nerve 6th CN).

Facial muscles- 6th somitomere (facial nerve).Stylopharengeus – 7th somitomere (glossopharengeal).Larenygeal muscles- 1st and 2nd somites (vagus).Tongue muscles- 1 to 4 somites (hypoglossal).Sternomastoid , tapezius – 3 to 7 somites (accessory)

FACIAL MUSCLES

DEVELOPMENTAL ANOMALIES OF THE FACE

Frontonasal Prominence central portion (white)

Frontonasal Prominence - Lateral nasal (purple)

Frontonasal Prominence - Medial nasal (green)

Pharyngeal Arch 1 - Maxillary prominence (yellow)

Pharyngeal Arch 1 - Mandibular prominence (orange)

Stomodeum (black)

Single or multifactorial

HISTORICAL BACKGROUND

There are four clinically significant types of congenital anomaly Malformation : A morphological defect of an organ, part

of an organ, or larger region of the body that results from an intrinsically abnormal developmental process.

Disruption :A morphological defect of an organ, part of an organ, or a larger region of the body that results from the extrinsic breakdown of, or an interference with, an originally normal developmental process

Deformation : An abnormal form, shape, or position of a part of the body that results from mechanical forces

Dysplasia : An abnormal organization of cells into tissue (s) and its morphological result (s).

TYPES:-

Cleft palate - A congenital fissure in the roof of the mouth, resulting from incomplete fusion of the palate during embryonic development.

Cleft lip - A congenital deformity characterized by a vertical cleft or pair of clefts in the upper lip, with or without involvement of the palate. Defective fusion of the medial nasal process with the maxillary process leads to cleft lip

GENETIC OR ENVIRONMENTAL

INCIDENCE

CLEFT LIP AND PALATE :-

Cleft lip is common among males while cleft palate is more common among females.

Unilateral clefts - 80% of the incidenceBilateral clefts - remaining 20%.

Most accepted.GROUP I:- cleft of the soft palate only.

GROUP II:-Cleft of the hard and soft palate to the incisive foramen.

GROUP III:-Complete unilateral cleft of the soft and hard palate, and the lip and alveolar ridge on one side.

GROUP IV:-Complete bilateral cleft of the soft and hard palate ,and the lip and alveolar ridge on both sides.

VEAU’S CLASSIFICATION

Kernahan’s stripped Y classification:-

DAVIS AND RITCHIE CLASSIFICATION(1922)

Classification by Fogh Andersen (1942)Millard’s modification of stripped Y

classificationSCHUCHARDT AND PFEIFER’S SYMBOLIC

CLASSIFICATION

DentalEstheticSpeech and HearingPsychologic

Problems associated with cleft lip and palate:-

Congenitally missing teeth (most commonly the upper laterals)

Presence of natal or neonatal teethPresence of supernumerary teethEctopically erupting teeth Anomalies of tooth morphologyEnamel hypoplasia

DENTAL PROBLEMS:-

MicrodontiaFused teethMacrodontiaMobile and early shedding of teeth due to

poor periodontal supportPosterior and anterior cross biteProtruding premaxillaDeep biteSpacing\crowding

The clefts involving the lip can result in facial disfigurement varing from mild to severe. The oro-facial structures may be malformed and congenitally missing. Deformities of nose can also occur. Thus esthetics is greatly affected.

AESTHETIC PROBLEMS

Cleft lip and palate are sometimes associated with disorders of the middle ear which may affect hearing. The presence of hearing problems can cause difficulties in language uptake and speech.

HEARING AND SPEECH

Due to their abnormal facial appearance they have to put up with staring, curiosity, pity, etc.,.

They also face problems in obtaining jobs and making friends.

Studies have shown that these patients fare badly in academics. This is usually as a result of hearing impairment, speech problems and frequent absence from school.

PSYCHOLOGICAL PROBLEMS

HereditaryEnvironment.Predisposing factors are increased maternal age.racialdecreased blood supply.

ETIOLOGY:-

TURNER’S SYNDROME:-Turner syndrome is caused by the absence of two complete copies of the X chromosome in some or all the cells.

CHROMOSOME ABNORMALITIES

Multiple eye findings including cataract, blue sclera.

Color BlindnessDepressed Corners of mouthHigh arched palateDental malocclusionMicrognathia

Features of Turner’s syndrome

TRISOMY 21/DOWNS SYNDROME/MONGOLISM:-C/F:-Hypoplastic maxilla and nasal bonesFlattening of nasal bridge, orbital ridges, and maxillaShort hard palateCleft lip/palate about 3 times frequency in normal

populationProtruding fissured tongue with hypertrophy of

papillaeDentition delayed, increased periodontal disease, and

reduced dental caries

CROUZONS SYNDROME/CRANIOFACIAL DYSOSTOSIS:-C/F:- Premature closure, especially of coronal

suture, occasionally lambdoidal.. Variable cranial form depending on order

and rate of progression of suture closure Optic nerve damage

High arched palate V-shaped maxillary dental arch. Crowding of the upper teeth. Class III Malocclusion Bilateral Atresia of Auditory meatus noted

occasionallyMental retardation occasionally seenanomalies of the hands and feet may or

may not occur.

craniofacial defect involving with neural crestal cells include:

Treachers colins yndromePierre Robin syndromeDe george anomalyOcculoauriculo vertbral spectrum(golden har syndrome)

NEURAL CREST CELLS AND CRANIOFACIAL DEFECTS

C/F:under development of the zygomatic bones,

mandibular hypoplasia, down slanting palpebral fissures, maformed external ears

Autosomal dominant trait with 60% cases

TREACHER COLLIN SYNDROME

Macrostomia Hypoplastic mandible with concave

undersurfaceHypoplastic zygomatic archescleft palateDental malocclusion commonPinna frequently deformed, crumpled

forward, or misplacedAbsence of external auditory canal

Altered first arch structureOccur independently or in association with other

malformationsDevelopment of mandible most severely affectedmicrognathia, cleft palate and glossoptosis (posteriorly

placed tongue)Robin’s syndrome may be due to genetic or

environmental factorsMay also occur as a deformationThe primary defect includes poor growth of the

mandible and as a result a posteriorly placed tongue that fails to drop from between the palatal shelves preventing their fusion

PIERRE ROBIN SYNDROME

Autosomal dominant traitC/F_-prominent supraorbital ridgesLong narrow faceHigh arched palateMandibular prognathismMyopiaBlue scleraeChest deformitiesHyperextensibility of jointsHerniasMuscular underdevelopment

MARFAN’S SYNDROME

Characterized by :have immunological deficiencies, hypocalcaemia

and poor prognosisOrigin of the defect is caused by abnormal

development of neural crest cells that contribute to formation of all affected structures

In addition to genetic causes , alcohol and maternal diabetes can produce such defect

defects in the palatemild differences in facial features,

DE GEORGE ANOMALY

craniofacial abnormalities involving the maxillary , temporal and zygomatic bones which are small and flat

Ear (anotia-no ear), eye(tumors and dermoid in eye balls)

Asymmetry -65% casesOther malformation-tetralogy of fallot

(con.heart disease) , malformations of kidney and intestine

Oculoauriculovertebral spectrum/Hemifacial Microstomia

AnkyloglossiaMacroglossiaMicroglossiaAglossiaBifid tongue

Fissured tongue

DEFECTS DURING DEVELOPMENT OF TONGUE

Also called cleft lip syndrome Also called lip pit syndrome

Characterized by : lip pits Absent teeth Isolated cleft lip and palate Abnormal fusion of palate and lips Both genders are equally affected Unilateral or bilateral lip pits classical symptoms is its association with cleft lip and cleft palate Usually medial or vermilion portion of the lower lip Associated with accessory salivary glands that empty into pits . Patients may have maxillary hypodontia. Missing maxillary pre molars

Van der woude syndrome

Localized hyperplasia/ hypertrophy of minor accessory glands

Aplasia :Development of xerostomiaFound in cases of hemifacial microsomia treacher collin’s syndrome

DEVELOPMENTAL ANOMALIES OF SALIVARY GLANDS

Atresia

Aberrancy

MacrostomiaMicrostomia

Congenital lip pits: malformation of lipsFollowing heridetary patternMay occur alone or with association with other

anamolies mainly cleft lip and palate due to notching of lip at an early stage of development with fixation of tissue at the base of the notch or from failure of complete union of embryonic lateral sulci of lip which persist and ultimately develop into typical pit.

Characterized by:Unilateral or bilateral depression On vermillion surface of either lipMore commonly on lower lipSparse mucous secretion may exude from the

base of the pit .lips might be swollen

Commissural pits:

Congenital deafnessAbsence of the tympanic cavity and external meatusAbnormal development of membranes and bony labyrinthMalformation of auditory ossicles and ear drum

Caused by:Rubella virusPoliomyelitisErythroblastosis fetalisDiabetesHypothyroidismtoxoplasmosis

DEVELOPMENTAL DEFECTS OF EAR

EXTERNAL EAR DEFECTS:-

Pre auricular appendages and pits:Skin tags and shallow depression - anterior to

the earPits may indicate abnormal development of

the auricular hillocks here as appendages may be caused by accessory hillocks

Bifid nose:

Proboscis:

DEVELOPMENTAL DEFECTS OF NOSE

AGNATHIAMICROGNATHIAMACROGNATHIAC/F:Mandibular protrusion (when mandible is affected)"Gummy smile" (when maxilla is affected)Ramus of mandible forms a less steep angle with

body of mandibleMandibular prognathism caused by excessive

condylar growthChin appears prominent

DEVELOPMENTAL DEFECTS OF THE JAWS

FACIAL HEMIHYPERTROPHY:-Asymptomatic growth of one or more body

partsInvolvement of one side of the faceFACIAL HEMIATROPHY:-Slowly progressive atrophy of soft tissue of

essentially half the face characterized by progressive wasting of sub cutaneous fat accompanied by atrophy of skin , cartilage , bone and muscle.

Occasionally spread one side of neck and body

Clinical features : commonly early sign is painless cleft near the midline of face or

forehead The marks the boundary between the normal and atrophic tissues Bluish hue may appear in the skin overlying atrophic fat Neurolgical disorders in 15 % cases may be accompanied by

pigmentation, pigmented facial naevi, contralateral jacksonian epilepsy , trigeminal nerve , occular complications.

More in female, more on left side Occurs mostly 1st and 2nd decadeDental abnormalities: incomplete root formation Delayed eruption Severe facial asymmetry difficulty with mastication

In 1897 Marie and Sainton coined the name cleidocranial dysostosis

Autosomal dominant(A gene on one of the non-sex chromosomes that is always expressed, even if only one copy is present) with wide variability in expression.

C/F:shortness of stature.Brachycephaly(head is disproportionately wide) with

bossing of frontal, parietal, and occipital bones;Mineralization of suturesLate or incomplete development of accessory sinuses

CLEIDOCRANIAL DYSPLASIA

Small sphenoid bones. Midfacial hypoplasia with low nasal bridge, narrow high-

arched palate. Hypertelorism(abnormal increased distance between 2

organs or body parts)small thorax with short oblique ribs.Dentition:-Late eruption, Malformed roots, Retention cysts, Enamel Hypoplasia, Caries,Supernumerary teeth.

Atresia (is a condition in which a body orifice or passage in the body is abnormally closed or absent) of the cavity at the external nares, at the posterior nasal aperture or in the cavity This may be unilateral or bilateralCongenital defect in the cribriform plate of ethmoid

bone may lead to communication between cranial cavity and nose

Nasal septum may not be in midline i.e., deflected to one side

Septum may be absentNasal cavity may communicate with the mouth

DEVELOPMENTAL DEFECTS OF NASAL CAVITIES

Teratogens are any agents from the environment that can cause harm to the developing fetus.

Many harmful agents cause damage only if exposure occurs during a sensitive period of prenatal development.

Critical factors that influence the degree of harm a teratogen will cause:

– The amount and length of exposure– Individual differences in susceptibility

HAZARDS IN PRENATAL DEVELOPMENT BY TERATOGENS

Damage from teratogens is not always evident at birth but may appear later in life.

Impact of teratogens often depends on quality of postnatal environment.

About 45% or more pregnancies end in miscarriage, that is, spontaneous abortion.

Most miscarried fetuses have severe defects, such as missing chromosomes, that make further development impossible.

Ninety percent of fetuses that survive the danger of miscarriage are born normal

RISK FACTORS:-SMOKINGALCOHOLDIETARY DEFICIENCIESDISEASES viz. cytomegalovirus, herpes virus, parvovirus

B19, rubella virus (German measles), syphilis, toxoplasmosis, Venezuelan equine encephalitis virus

DRUGS viz Aspirin- pregnant women - blood disorders in offspring.Thalidomide- deformations of the eyes, nose, ears cleft plate, facial palsy

and fusing of fingers and toe , dislocations of the hip joint and malformations of the heart and digestive and urinary tract

Illegal drugs Marijuana: prenatal exposure to marijuana leads to infants reduced weight and size, short term changes in behaviour e.g. increased startle and a high pitched cry.Cocaine: effect of maternal cocaine use - children tend to be impulsive, highly distractable and difficult to control and to have problems in language development as they grow old.

Father’s exposure to toxin viz Lead , Mercury , Radiation.

Fetal alcohol syndrome

Congenital facial paralysis:Traumatic congenital facial nerve paralysis usually resolves spontaneously and does not require surgery.

Cephalic disorders are congenital conditions that stem from damage to, or abnormal development of, the budding nervous system.ANENCEPHALY is a neural tube defect that

occurs when the cephalic (head) end of the neural tube fails to close, usually between the 23rd and 26th days of pregnancy, resulting in the absence of a major portion of the brain, skull, and scalp.

CEPHALIC DISORDERS

HYDRANENCEPHALY is a rare condition in which the cerebral hemispheres are absent and replaced by sacs filled with cerebrospinal fluid.

INIENCEPHALY is a rare neural tube defect that combines extreme retroflexion (backward bending) of the head with severe defects of the spine.

MEGALENCEPHALY, also called macrencephaly, is a condition in which there is an abnormally large, heavy, and usually malfunctioning brain.

MICROCEPHALY is a neurological disorder in which the circumference of the head is smaller than average for the age and gender of the infant or child

The human face is a fascinating study of physiology and psychology. The amount of information a human face can relay is unending. Humans are capable of making 10,000 unique facial expressions! While the face is complicated, it is also our most useful and most underestimated tool for communication.

CONCLUSION : -