Development of Face /certified fixed orthodontic courses by Indian dental academy
1. BRANCHIAL ARCHES
2. DEVELOPMENT OF FACE
INDIAN DENTAL ACADEMY
Leader in continuing dental education
Develop during the late somite period
i.e. 4th week I.U
The mesoderm of the ventral foregut region
Six distinct bilateral mesenchymal swellings
Branchial arches separated on the external
aspect of the embryo
Correspond internally with outpouching of
the elongated pharynx
Each pair of Branchial arches contain a
basic set of structures.
1. Cartilage component.
2. Muscular component.
3. Vascular component.
4. Nervous component.
Cartilage component :
Adapt to form Bony, Cartilagenous or
Give rise to special visceral muscles
composed of straited muscle fibers.
Provides necessary blood supply.
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
1st BRANCHIAL ARCH
Precursor of both the jaws:
Maxilla + Mandible
Initially gives rise to a large mandibular
Gives rise to a small maxillary prominence
which extends cranioventrally.
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.
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.
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
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.
2nd BRANCHIAL ARCH
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.
2. Muscles :
-- Post. Belly of Digastric.
-- Mimetic muscles of face.
-- Levator Veli Palatini.
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.
Anomalies associated with
Deficient development of the branchial arches
result in syndromes according to the arch
First arch syndromes :
- Treacher Collins syndrome (mandibular dysostosis)
- Pierre Robin syndrome (micrognathia+cleft palate)
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.
-- Induces the formation of :
Inner ear apparatus
Upper third of face
Rhombencephalic organizing center :
-- Caudal in relation to the Prosencephalic
Induces the formation of:
-- Middle and lower third of the face.
-- Middle and external ears.
Oral development in embryo is demarcated
extremely early in life by the appearance
of the prechordal plate (14th day)
Oropharyngeal membrane is a temporary
bilaminar membrane which functions
1. Site of junction of ectoderm and
2. Demarcates the stomodeum from the
rest. i.e. initial demarcation of
Rapid development of the cranial portion
than the caudal portion.
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.
Therefore during 5th to 8 wks.
- Head constitutes nearly half the
total body size.
This explains the
“Cephalo-caudal growth gradient”
The face derives from five prominences that
surround a central depression,
--The Stomodeum ( Future mouth)
-- Single median Frontonasal
-- Paired Maxillary + Mandibular
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
Demarcate the medial and
Precursors to Anterior nares
Next, is the union of the facial prominences
by either of the 2 below
1. Merging of the frontonasal, maxillary
and mandibular prominences.
2. Fusion of the central maxillonasal
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
Failure of normal disintegration of nasal fin
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)
Midline merging of median nasal prominences
Philtrum of upper lip
Tip of the nose.
Post. Merging of Medial nasal processes
Median primary palate
Future site of 4 upper incisors
Midline merging of the paired
Lower jaw + Lower lip
-- First to get definitely established .
Lateral merging of maxillary and
Commisures of mouth
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.
Specific structures :
Complex structure with contributions
-- Frontal prominence
-- Merged MNP
- Median ridge
-- Lateral nasal Prominence - Alae
-- Cartilage nasal capsule - Septum
+ Nasal conchae
From frontonasal process
From median nasal process
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
The mesodermal basis of lateral part
The mesodermal basis of median part
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.
The fused mandibular prominences give
rise to the lower lip and jaw.
After the formation of the lips the
maxillary and mandibular processes undergo
progressive fusion to form the cheeks.
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
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