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1. 1. BRANCHIAL ARCHES
2. DEVELOPMENT OF FACE

2. INDIAN DENTAL ACADEMY
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3. BRANCHIAL ARCHES



Develop during the late somite period
i.e. 4th week I.U
The mesoderm of the ventral foregut region
gets segmented
Six distinct bilateral mesenchymal swellings
BRANCHIAL ARCHES

4. Development of Branchial Arches

6. 
Branchial arches separated on the external
aspect of the embryo
BRANCHIAL GROOVES

7. 
Correspond internally with outpouching of
the elongated pharynx
PHARYNGEAL POUCHES

8. 
Each pair of Branchial arches contain a
basic set of structures.
1. Cartilage component.
2. Muscular component.
3. Vascular component.
4. Nervous component.

10. 
Cartilage component :
Adapt to form Bony, Cartilagenous or
Ligamentous structures

Muscle component:
Give rise to special visceral muscles
composed of straited muscle fibers.

Vascular component:
Provides necessary blood supply.

11. 
Nerve component :
Nerve fibers of special cranial nerves
Enter mesoderm of branchial arches
Initiate muscle development in the mesoderm
Migrate and adapt to the brachial arches

12. 


1st BRANCHIAL ARCH
(Mandibular arch)
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.
Maxilla

14. COMPONENTS OF 1st ARCH
1. Cartilage : MECKEL’S CARTILAGE
--Arises 41st – 45th Day I.U
--It provides a template for subsequent
development of the mandible.

15. 
Derivatives of Meckel’s Cartilage :
-- Mental Ossicle (Endochondral Oss.)
-- Head and neck of Malleus.
-- Short crus of the Incus.
-- Ant. Ligament of the Malleus.
-- Sphenomandibular Ligament.

17. 2. 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 Ext.Carotid.Art

18. 4. Nerve components:
-- Mandibular division of Trigeminal.N
( 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.

19. 2nd BRANCHIAL ARCH
(Hyoid Arch)

Components:
1. Cartilage : Reichert’s Cartilage
(45th – 48th I.U)
-- Greater part of the third ear ossicle.
-- Stapes, Malleus and incus.
-- Styloid process of the temporal bone.
-- Stylohyoid ligament.
-- Lessor horn of sphenoid.
-- Cranial part - Body of Hyoid.
-- Segments of the facial canal.

21. 2. Muscles :
-- Stapedius
-- Stylohyoid
-- Post. Belly of Digastric.
-- Mimetic muscles of face.
-- Levator Veli Palatini.

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

23. Muscles

24. Nerves ass. with Branchial arches

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

27. Trecher Collins syndrome

28. DEVELOPMENT OF FACE

Development of the head depends upon
inductive activities of 2 organizing centers
-- Prosencephalic
-- Rhombencephalic

29. ORGANIZING CENTER’S

30. 
Prosencephalic organizing center :
-- Derived from prechordal mesoderm
that migrates from the primitive streak.
-- Situated at the rostral end of the
notochord below the fore brain.

31. -- Induces the formation of :



Visual apparatus
Inner ear apparatus
Upper third of face

32. 
Rhombencephalic organizing center :
-- Caudal in relation to the Prosencephalic
centre.
Induces the formation of:
-- Middle and lower third of the face.
-- Middle and external ears.

33. 
Oral development in embryo is demarcated
extremely early in life by the appearance
of the prechordal plate (14th day)
+
Endodermal
Thickening
Oropharyngeal Membrane

36. 
Oropharyngeal membrane is a temporary
bilaminar membrane which functions
as:
1. Site of junction of ectoderm and
endoderm.
2. Demarcates the stomodeum from the
rest. i.e. initial demarcation of
the
future mouth.

37. Cranial portion

Embryo
Caudal portion

Rapid development of the cranial portion
than the caudal portion.

39. 
This differential rates of growth results in the
formation of pear-shaped embryonic disc.
-- Cranial/Head region forming the
expanded portion of the pear.

Further, the 3 germ layers show specific
development by the middle of the 3 rd
week in the cranial portion as compared to 4-5
wks in the caudal portion.

40. 

Therefore during 5th to 8 wks.
- Head constitutes nearly half the
total body size.
This explains the
“Cephalo-caudal growth gradient”

41. 
The face derives from five prominences that
surround a central depression,
--The Stomodeum ( Future mouth)

Prominences:
-- Single median Frontonasal
-- Paired Maxillary + Mandibular

42. 
Frontonasal prominence :
Surrounds the forebrain
sprouts lateral optic diverticula
Eyes

43. 
The frontal portion of the prominence
b/w the eyes forms the Forehead.

44. 
At the infero-lateral corners, thickened
ectodermal nasal placodes arise

45. 
These placodes induced by the underlying
olfactory nerves
Invaginate
Demarcate the medial and
lateral nasal
prominences.
Nasal pits
Precursors to Anterior nares

47. 
Next, is the union of the facial prominences
by either of the 2 below
developmental events.
1. Merging of the frontonasal, maxillary
and mandibular prominences.
OR
2. Fusion of the central maxillonasal
components.

49. 
Merging is completed as a result of
proliferation of the underlying mesenchyme
into the intervening grooves.

The above is guided by the disintegration of
the contacting surface epithelium b/w the
processes termed as Nasal fin

50. 
Failure of normal disintegration of nasal fin
Due to:
1. Cell death
2. Mesenchymal Leads to cleft of upper lip and
transformation anterior palate
(Due to prevention of merging
of mesenchyme of max. and
medial nasal processes)

52. 
Midline merging of median nasal prominences
forms :
 Philtrum of upper lip
Median tubercle.
Tip of the nose.
Primary palate.

53. 
Post. Merging of Medial nasal processes
Median primary palate
Premaxilla
Future site of 4 upper incisors

55. 
Midline merging of the paired
mandibular prominences
Lower jaw + Lower lip
-- First to get definitely established .

56. 
Lateral merging of maxillary and
mandibular prominences.
Commisures of mouth

59. 
All the regions of the face grow in proportion
to each other and equally.

i.e. any malproportioning at this time may
form a basis for craniofacial defects.

60. Various Cranio- facial defects

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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)

61. 
Specific structures :
-- Nose
-- Cheeks
-- Lips
-- Tongue

62. 
Nose :
Complex structure with contributions
from :
-- Frontal prominence
- Bridge
-- Merged MNP
- Median ridge
+ Tip
-- Lateral nasal Prominence - Alae
-- Cartilage nasal capsule - Septum
+ Nasal conchae

63. From frontonasal process
From median nasal process

64. 
Lips :
1. Upper lip :
As the maxillary, lateral and nasal
processes fuse and the nares come close to
each other the upper lip forms from the
-- Maxillary process
-- Frontanasal process

66. 

The mesodermal basis of lateral part
Maxillary process
The mesodermal basis of median part
Frontonasal process

67. 
The ectoderm of the max. process overgrows
the philtrum to meet the opposite side.

Therefore the skin of the entire upper lip is
formed by the maxillary process, and
innervated by the maxillary nerves.

69. 
The fused mandibular prominences give
rise to the lower lip and jaw.
Cheeks :
After the formation of the lips the
maxillary and mandibular processes undergo
progressive fusion to form the cheeks.

71. 
Tongue :
Ant 2/3rd :
-- Median triangular elevation in the
floor of the primitive pharynx ant. to foramen
caecum termed as Median tongue bed.
( Tuberculum Impar)
-- Mesenchyme of the 1st arch give rise
to 2 distal tongue beds on either side of median
tongue bed.

72. 
Median and distal tongue beds rapidly
increase in size and fuse together to form
the ant.2/3rd of the tongue.

2 elevations copula and the hypobranchial
eminence form the posterior 1/3rd of the
tongue.

74. 
External ear :
1ST Brachial groove
-- External acoustic meatus

75. • Auricle derived from
the auricular hillocks
i.e. the mesoderm of
the 1st and 2nd
Branchial arches.

76. 
BIBLIOGRAPHY
-- G.H.SPERBER
(Cranifacial Embryology)
-- KIETH.L.MOORE
(The Developing Human)
-- KIETH.L.MOORE
(Altas of Human Embryology)
-- WILLIAM.R.PROFFIT
(Contemporary Orthodontics)

77. Thank you
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