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1. 1.1. BRANCHIAL ARCHESBRANCHIAL ARCHES
2.2. DEVELOPMENT OF FACEDEVELOPMENT OF FACE

2. BRANCHIAL ARCHESBRANCHIAL ARCHES
 Develop during the late somite periodDevelop during the late somite period
i.e. 4i.e. 4thth
week I.Uweek I.U
 The mesoderm of the ventral foregut regionThe mesoderm of the ventral foregut region
gets segmentedgets segmented
 Six distinct bilateral mesenchymal swellingsSix distinct bilateral mesenchymal swellings
BRANCHIAL ARCHESBRANCHIAL ARCHES
 Develop during the late somite periodDevelop during the late somite period
i.e. 4i.e. 4thth
week I.Uweek I.U
 The mesoderm of the ventral foregut regionThe mesoderm of the ventral foregut region
gets segmentedgets segmented
 Six distinct bilateral mesenchymal swellingsSix distinct bilateral mesenchymal swellings
BRANCHIAL ARCHESBRANCHIAL ARCHES

3. Development of Branchial ArchesDevelopment of Branchial Arches

5.  Branchial arches separated on the externalBranchial arches separated on the external
aspect of the embryoaspect of the embryo
BRANCHIAL GROOVESBRANCHIAL GROOVES

6.  Correspond internally with outpouching ofCorrespond internally with outpouching of
the elongated pharynxthe elongated pharynx
PHARYNGEAL POUCHESPHARYNGEAL POUCHES

7.  Each pair of Branchial arches contain aEach pair of Branchial arches contain a
basic set of structures.basic set of structures.
1. Cartilage component.1. Cartilage component.
2. Muscular component.2. Muscular component.
3. Vascular component.3. Vascular component.
4. Nervous component4. Nervous component..

9.  Cartilage componentCartilage component ::
Adapt to form Bony, Cartilagenous orAdapt to form Bony, Cartilagenous or
Ligamentous structuresLigamentous structures

Muscle componentMuscle component::
Give rise to special visceral musclesGive rise to special visceral muscles
composed of straited muscle fibers.composed of straited muscle fibers.
 Vascular componentVascular component::
Provides necessary blood supply.Provides necessary blood supply.

10.  Nerve componentNerve component ::
Nerve fibers of special cranial nervesNerve fibers of special cranial nerves
Enter mesoderm of branchial archesEnter mesoderm of branchial arches
Initiate muscle development in the mesodermInitiate muscle development in the mesoderm
Migrate and adapt to the brachial archesMigrate and adapt to the brachial arches

11. 11stst
BRANCHIALBRANCHIAL ARCHARCH
(Mandibular arch)(Mandibular arch)
 Precursor of both the jaws:Precursor of both the jaws:
Maxilla + MandibleMaxilla + Mandible
 Initially gives rise to a large mandibularInitially gives rise to a large mandibular
prominence.prominence.
 Gives rise to a small maxillary prominenceGives rise to a small maxillary prominence
which extends cranioventrally.which extends cranioventrally.
MaxillaMaxilla

13. COMPONENTS OF 1COMPONENTS OF 1stst
ARCHARCH
11.. CartilageCartilage :: MECKEL’S CARTILAGEMECKEL’S CARTILAGE
--Arises 41--Arises 41stst
– 45– 45thth
Day I.UDay I.U
--It provides a template for subsequent--It provides a template for subsequent
development of the mandible.development of the mandible.

14.  Derivatives of Meckel’s CartilageDerivatives of Meckel’s Cartilage::
-- Mental Ossicle (Endochondral Oss.)-- Mental Ossicle (Endochondral Oss.)
-- Head and neck of Malleus.-- Head and neck of Malleus.
-- Short crus of the Incus.-- Short crus of the Incus.
-- Ant. Ligament of the Malleus.-- Ant. Ligament of the Malleus.
-- Sphenomandibular Ligament.-- Sphenomandibular Ligament.

16. 2.2. Musculature Derived from 1Musculature Derived from 1stst
archarch::
-- Muscles of Mastication.-- Muscles of Mastication.
-- Mylohyoid Muscle.-- Mylohyoid Muscle.
-- Ant. Belly of Digastric.-- Ant. Belly of Digastric.
-- Tensor Tympani.-- Tensor Tympani.
-- Tensor Veli Palatini Muscles.-- Tensor Veli Palatini Muscles.
3.3. Arterial ComponentArterial Component::
-- Part of Maxillary and Ext.Carotid.Art-- Part of Maxillary and Ext.Carotid.Art

17. 4.4. Nerve components:Nerve components:
-- Mandibular division of Trigeminal.N-- Mandibular division of Trigeminal.N
( Vth Cranial Nerve)( Vth Cranial Nerve)
-- Sensory component supplies-- Sensory component supplies
: Mandible and covering mucosa.: Mandible and covering mucosa.
: Mandibular teeth including Gingiva.: Mandibular teeth including Gingiva.
: Mucosa of ant. 2/3 of Tongue.: Mucosa of ant. 2/3 of Tongue.
: Floor of the mouth.: Floor of the mouth.
: Skin of the lower third of Face.: Skin of the lower third of Face.

18. (Hyoid Arch)(Hyoid Arch)
 Components:Components:
1.1. CartilageCartilage :: Reichert’s CartilageReichert’s Cartilage
(45(45thth
– 48– 48thth
I.U)I.U)
-- Greater part of the third ear ossicle.-- Greater part of the third ear ossicle.
-- Stapes, Malleus and incus.-- Stapes, Malleus and incus.
-- Styloid process of the temporal bone.-- Styloid process of the temporal bone.
-- Stylohyoid ligament.-- Stylohyoid ligament.
-- Lessor horn of sphenoid.-- Lessor horn of sphenoid.
-- Cranial part - Body of Hyoid.-- Cranial part - Body of Hyoid.
-- Segments of the facial canal.-- Segments of the facial canal.
22ndnd
BRANCHIALBRANCHIAL ARCHARCH

20. 2.2. MusclesMuscles ::
-- Stapedius-- Stapedius
-- Stylohyoid-- Stylohyoid
-- Post. Belly of Digastric.-- Post. Belly of Digastric.
-- Mimetic muscles of face.-- Mimetic muscles of face.
-- Levator Veli Palatini.-- Levator Veli Palatini.

21. 3. Nerve3. Nerve ::
-- Facial / VII Cranial nerve.-- Facial / VII Cranial nerve.
-- Special sensory component-- Special sensory component
- Chorda tympani nerve- Chorda tympani nerve
(Ant 2/3(Ant 2/3rdrd
of Tongue)of Tongue)
4. Artery4. Artery ::
-- Stapedial artery-- Stapedial artery
- Transient i.e. disappears during fetal life.- Transient i.e. disappears during fetal life.

22. Muscles

23. Nerves ass. with Branchial arches

25. Anomalies associated withAnomalies associated with
branchial archesbranchial arches
 Deficient development of the branchial archesDeficient development of the branchial arches
result in syndromes according to the archresult in syndromes according to the arch
involved.involved.
 First arch syndromes :First arch syndromes :
- Agnathia- Agnathia
- Microstomia- Microstomia
- Treacher Collins syndrome (mandibular dysostosis)- Treacher Collins syndrome (mandibular dysostosis)
- Pierre Robin syndrome (micrognathia+cleft palate)- Pierre Robin syndrome (micrognathia+cleft palate)

26. Trecher Collins syndromeTrecher Collins syndrome

27. DEVELOPMENT OF FACEDEVELOPMENT OF FACE
 Development of the head depends uponDevelopment of the head depends upon
inductive activities ofinductive activities of 2 organizing centers2 organizing centers
-- Prosencephalic-- Prosencephalic
-- Rhombencephalic-- Rhombencephalic

28. ORGANIZING CENTER’SORGANIZING CENTER’S

29.  Prosencephalic organizing center :Prosencephalic organizing center :
-- Derived from prechordal mesoderm-- Derived from prechordal mesoderm
that migrates from the primitive streak.that migrates from the primitive streak.
-- Situated at the rostral end of the-- Situated at the rostral end of the
notochord below the fore brain.notochord below the fore brain.

30. -- Induces the formation of :-- Induces the formation of :
 Visual apparatusVisual apparatus
 Inner ear apparatusInner ear apparatus
 Upper third of faceUpper third of face

31.  Rhombencephalic organizing centerRhombencephalic organizing center ::
-- Caudal in relation to the Prosencephalic-- Caudal in relation to the Prosencephalic
centre.centre.
Induces the formation ofInduces the formation of::
-- Middle and lower third of the face.-- Middle and lower third of the face.
-- Middle and external ears.-- Middle and external ears.

32.  Oral development in embryo is demarcatedOral development in embryo is demarcated
extremely early in life by the appearanceextremely early in life by the appearance
of theof the prechordal plateprechordal plate (14(14thth
day)day)
++
EndodermalEndodermal
ThickeningThickening
Oropharyngeal MembraneOropharyngeal Membrane

35.  Oropharyngeal membrane is aOropharyngeal membrane is a temporarytemporary
bilaminar membrane which functionsbilaminar membrane which functions
as:as:
1.1. Site of junction of ectoderm andSite of junction of ectoderm and
endoderm.endoderm.
2.2. Demarcates the stomodeum from theDemarcates the stomodeum from the
rest.rest. i.e. initial demarcation ofi.e. initial demarcation of
thethe future mouth.future mouth.

36. Cranial portionCranial portion
 EmbryoEmbryo
Caudal portionCaudal portion
 Rapid development of the cranial portionRapid development of the cranial portion
than the caudal portion.than the caudal portion.

38. 
This differential rates of growth results in theThis differential rates of growth results in the
formation offormation of pear-shapedpear-shaped embryonic disc.embryonic disc.
-- Cranial/Head region forming the-- Cranial/Head region forming the
expanded portion of the pear.expanded portion of the pear.
 Further, the 3 germ layers show specificFurther, the 3 germ layers show specific
development by the middle of the 3development by the middle of the 3rdrd
week in the cranial portion as compared to 4-5week in the cranial portion as compared to 4-5
wks in the caudal portion.wks in the caudal portion.

39.  Therefore during 5Therefore during 5thth
to 8 wks.to 8 wks.
- Head constitutes nearly half the- Head constitutes nearly half the
total body size.total body size.
 This explains theThis explains the
““Cephalo-caudal growth gradient”Cephalo-caudal growth gradient”

40.  The face derives from five prominences thatThe face derives from five prominences that
surround a central depression,surround a central depression,
--The Stomodeum--The Stomodeum ( Future mouth)( Future mouth)
 Prominences:Prominences:
---- Single median FrontonasalSingle median Frontonasal
-- Paired Maxillary + Mandibular-- Paired Maxillary + Mandibular

41.  Frontonasal prominenceFrontonasal prominence ::
Surrounds the forebrainSurrounds the forebrain
sprouts lateral optic diverticulasprouts lateral optic diverticula
EyesEyes

42. 
TheThe frontal portionfrontal portion of the prominenceof the prominence
b/wb/w the eyes forms thethe eyes forms the Forehead.Forehead.

43. 
At the infero-lateral corners, thickenedAt the infero-lateral corners, thickened
ectodermalectodermal nasal placodesnasal placodes arisearise

44.  TheseThese placodesplacodes induced by the underlyinginduced by the underlying
olfactory nervesolfactory nerves
InvaginateInvaginate
Demarcate the medial andDemarcate the medial and
lateral nasallateral nasal
prominences.prominences.
Nasal pitsNasal pits
Precursors toPrecursors to Anterior naresAnterior nares

46.  Next, is the union of the facial prominencesNext, is the union of the facial prominences
by either of the 2 belowby either of the 2 below
developmental events.developmental events.
1. Merging of the frontonasal, maxillary1. Merging of the frontonasal, maxillary
and mandibular prominences.and mandibular prominences.
OROR
2. Fusion of the central maxillonasal2. Fusion of the central maxillonasal
components.components.

48.  Merging is completed as a result ofMerging is completed as a result of
proliferation of the underlyingproliferation of the underlying mesenchymemesenchyme
into the intervening grooves.into the intervening grooves.
 The above is guided by the disintegration ofThe above is guided by the disintegration of
thethe contacting surface epitheliumcontacting surface epithelium b/w theb/w the
processes termed asprocesses termed as Nasal finNasal fin

49.  FailureFailure of normal disintegration ofof normal disintegration of nasal finnasal fin
Due toDue to::
1. Cell death1. Cell death
2. Mesenchymal2. Mesenchymal
transformationtransformation
Leads to cleft of upper lip and
anterior palate
(Due to prevention of merging
of mesenchyme of max. and
medial nasal processes)

51.  Midline merging of median nasal prominencesMidline merging of median nasal prominences
forms :forms :
 Philtrum of upper lipPhiltrum of upper lip
Median tubercle.Median tubercle.
Tip of the nose.Tip of the nose.
Primary palate.Primary palate.

52.  Post. Merging of Medial nasal processesPost. Merging of Medial nasal processes
Median primary palateMedian primary palate
PremaxillaPremaxilla
Future site of 4 upper incisorsFuture site of 4 upper incisors

54.  Midline merging of the pairedMidline merging of the paired
mandibular prominencesmandibular prominences
Lower jaw + Lower lipLower jaw + Lower lip
-- First to get definitely established-- First to get definitely established..

55.  Lateral merging of maxillary andLateral merging of maxillary and
mandibular prominences.mandibular prominences.
Commisures of mouthCommisures of mouth

58.  All the regions of the face grow inAll the regions of the face grow in proportionproportion
to each other and equally.to each other and equally.
 i.e. anyi.e. any malproportioningmalproportioning at this time mayat this time may
form a basis forform a basis for craniofacial defects.craniofacial defects.

59. Various Cranio- facial defectsVarious Cranio- facial defects
 Acephaly (Absence of head)
 Anencephaly (Absence of brain)
 Acrania (Absent skull)
 Acalvaria (Roofless skull)
 Cranioschisis (Fissured cranium)
 Premaxillary agenesis (Median cleft lip/palate)
 Premaxillary dysgenesis (Bilateral cleft lip/palate)
 Agnathia (Absent mandible)

60.  Specific structuresSpecific structures ::
-- Nose-- Nose
-- Cheeks-- Cheeks
-- Lips-- Lips
-- Tongue-- Tongue

61.  NoseNose ::
Complex structure with contributionsComplex structure with contributions
from :from :
-- Frontal prominence --- Frontal prominence - BridgeBridge
-- Merged MNP --- Merged MNP - Median ridgeMedian ridge
+ Tip+ Tip
-- Lateral nasal Prominence --- Lateral nasal Prominence - AlaeAlae
-- Cartilage nasal capsule --- Cartilage nasal capsule - SeptumSeptum
+ Nasal conchae+ Nasal conchae

62. From frontonasal process
From median nasal processFrom median nasal process

63.  LipsLips ::
1.1. Upper lipUpper lip ::
As the maxillary, lateral and nasalAs the maxillary, lateral and nasal
processes fuse and the nares come close toprocesses fuse and the nares come close to
each other the upper lip forms from theeach other the upper lip forms from the
-- Maxillary process-- Maxillary process
-- Frontanasal process-- Frontanasal process

65.  The mesodermal basis of lateral partThe mesodermal basis of lateral part
Maxillary processMaxillary process
 The mesodermal basis of median partThe mesodermal basis of median part
Frontonasal processFrontonasal process

66.  The ectoderm of the max. processThe ectoderm of the max. process overgrowsovergrows
the philtrum to meet the opposite side.the philtrum to meet the opposite side.
 Therefore the skin of the entire upper lip isTherefore the skin of the entire upper lip is
formed by the maxillary process, andformed by the maxillary process, and
innervated by the maxillary nerves.innervated by the maxillary nerves.

68.  The fused mandibular prominences giveThe fused mandibular prominences give
rise to the lower lip and jaw.rise to the lower lip and jaw.
Cheeks :Cheeks :
After the formation of the lips theAfter the formation of the lips the
maxillary and mandibular processes undergomaxillary and mandibular processes undergo
progressive fusion to form the cheeks.progressive fusion to form the cheeks.

70.  TongueTongue ::
Ant 2/3Ant 2/3rdrd
::
-- Median triangular elevation in the-- Median triangular elevation in the
floor of the primitive pharynx ant. to foramenfloor of the primitive pharynx ant. to foramen
caecum termed ascaecum termed as Median tongue bed.Median tongue bed.
( Tuberculum Impar)( Tuberculum Impar)
-- Mesenchyme of the 1-- Mesenchyme of the 1stst
arch give risearch give rise
toto 2 distal tongue beds2 distal tongue beds on either side of medianon either side of median
tongue bed.tongue bed.

71.  Median and distal tongue beds rapidlyMedian and distal tongue beds rapidly
increase in size and fuse together to formincrease in size and fuse together to form
the ant.2/3the ant.2/3rdrd
of the tongue.of the tongue.
 2 elevations2 elevations copulacopula and theand the hypobranchialhypobranchial
eminence form theeminence form the posterior 1/3posterior 1/3rdrd
of theof the
tongue.tongue.

73.  External earExternal ear ::
11STST
Brachial grooveBrachial groove
-- External acoustic meatus-- External acoustic meatus

74. • AuricleAuricle derived fromderived from
thethe auricular hillocksauricular hillocks
i.e. the mesoderm ofi.e. the mesoderm of
the 1st and 2ndthe 1st and 2nd
Branchial arches.Branchial arches.

75.  BIBLIOGRAPHYBIBLIOGRAPHY
-- G.H.SPERBER
(Cranifacial Embryology)
-- KIETH.L.MOORE
(The Developing Human)
-- KIETH.L.MOORE
(Altas of Human Embryology)
-- WILLIAM.R.PROFFIT
(Contemporary Orthodontics)