Development of the face, nose, palate

Development of

Face
Nose
Prof. Mohamed Autifi

Development of the face







The face develops from 5 mesenchymal
prominences (swellings or processes) that
appear in the 4th week.
One Frontonasal prominence (formed by
proliferation of mesenchyme and ectoderm
ventral to the forebrain).
Two maxillary swellings (from 1st pharyngeal
arch).
Two mandibular swellings (from 1st pharyngeal
arch).

Development of the face


These 5 prominences surround the stomodeum
(primitive mouth) , cranially , laterally and caudally.


Mouth:
Primitive oral cavity: develops from:
a)An ectodermal depression between frontonasal

prominence and the first pharyngeal arch: the
stomodeum. Its floor is closed by the buccopharyngeal
membrane.
b)An endormal part: is the cranial end of the pharynx.
The buccal membrane degenerates during the 4 th week,
i.e. the 2 parts continue together.


Lips & gingivae:
They develop as a linear ectodermal thickenings
around the stomodeum  labiogingival laminae.
They grow into mesenchyme, then degenerate
forming labiogingival grooves separating lips
from gingivae.
A small area of laminae persists in median plane
forming frenulum of the lip.


Salivary glands:
Appear as epithelial buds from oral cavity.
Parotid gland: The first to appear, early in 6th week, from oral
ectoderm, near angle of stomodeum. It forms a tube, extends into
cheek’s mesoderm.
Its Proximal part forming the parotid duct;
Its distal end breaks to form the glandular alveoli.
Capsule & connective septae develop from surrounding mesoderm.
 The duct opening is carried to open inside the cheek.

Submandibular gland: Appear late in 6th week, from an endodermal
bud in floor of stomodeum (alveolo- lingual groove).
Develops in same way as parotid gland.

Sublingual gland: appear in 8th week, from multiple endodermal buds
in the alveolo-lingual groove.


I. Frontonasal process





Bilateral ectodermal thickenings above the lateral angle of
stomodeum form the nasal placodes.
By the 5th weak, the nasal placodes are invaginated to form
the nasal pits, thus the nasal placodes are divided into
medial and lateral nasal folds (promeninces).
The two medial nasal folds fuse to form median nasal fold.


Fate of the frontonasal process
The lateral nasal folds form
the alae of the nose.
 The nasal pits get deeper and
they form the primitive nasal
cavities.
 The medain nasal fold forms:
1. Forehaed
2. Middle of the nose and nasal
septum
3. Filtrum of the upper lip
4. Premaxilla



II. Maxillary processes



The maxillary process develops as mesodermal
proliferation from the 1st pharyngeal arch.
It grows ventrally and medially, compressing the
medial nasal folds towards the middle line and
converting them into one median nasal fold.





The maxillary processes are separated from the
lateral nasal folds by the nasolacrimal groove.
The lower part of the groove will form the
nasolacrimal duct while its upper part will form the
lacrimal sac.


A

palatine shelf arises from the medial
aspects of each maxillary process.

 Both

shelves are approximated towards
each other and fuse together and with
the premaxilla forming the hard and
soft palate. Thus the nasal cavity
becomes separated from the oral cavity.

Fate of maxillary processes
1. Cheeks
2. Upper lip except the filtrum
3. Palate except the premaxilla


Frnotnasal
process

III. The mandibular processes
 Develop

from the mesenchyme of the 1st
pharyngeal arch.

 Fate

:

1. Lower jaw
2. Lower lip
3. Floor of the mouth

Development
Of
Nasal cavities


In the 6th week, the nasal pits deepen ➪ nasal sacs,
grow dorsally, separated from oral cavity by
oronasal membrane, which soon ruptures.
Both cavities continue together via primitive
choanae, dorsal to 1ry palate. Later, choanae lies bet
nasal cavity & pharynx.
Lateral wall develops 3 shelf-like projections:
Superior, middle & inferior conchae


Development of Nasal cavity
28 day



5 wk

6 wk

7 wk

12 wk


In the roof of each cavity, the ectoderm shows
thickened patch, olfactory epithelium, forming
receptor cells, they are ciliated bipolar neurons.
Their axons form the olfactory nerves.

Paranasal air sinuses:
-They develop after birth, except maxillary

sinus which appears late in foetal life.
-They develop as diverticula of lateral nasal walls,
extend into their bones.
-They reach mature size during puberty.

Development
Of
Palate


Medial growth of the two maxillary processes
leading to fusion of the two medial nasal folds
in midline ➪ intermaxillary segment ➪
philtrum of upper lip, 4 incisors & 1ry palate
(premaxilla).


Early in 6th week, Two medial outgrowths
from maxillary processes called, palatine
shelves, fuse along palatine raphe forming
Secondary palate. It fuses with the 1ry
palate at the incisive foramen ➪ definitive
palate.
Anterior part of definitive palate ➪ hard
palate, while post part ➪ soft palate


Nasal septum

develops from fronto-nasal prominence & medial
nasal folds; fuses with definitive palate.

Congenital anomalies
1. Anomalies of the mouth :







Microstomia : small mouth opening
Macrostomia : large mouth opening
Agnathia : absence lower jaw
Microstomia and single nostril
Micrognathia : small lower jaw
Anodontia : absence of the teeth

2. Anomalies of the nose :



Stenosis of nostrils
Deviation of the nasal septum

Macrostomia

3. Anomalies of the
face and palate :
1.Fusion dermoid: Cystic
swelling developed along
line of fusion of face

2. Oblique facial cleft:
Due to failure of fusion
between maxillary &
frontonasal processes
(at nasolacrimal groove).
May include cleft upper
lip.


3. Cleft upper lip (harelip): Unilateral or
bilateral. The former is most common anomaly
of head & neck (1:1000). Due to failure of
fusion of maxillary process with medial nasal
fold.
4. Cleft lower lip: Usually central
5. Cleft uvula

Median cleft of the lower lip
Prof. Mohamed A. Autifi

6. Cleft palate: (1:2500 births)

a) Anteriorly: Anterior to incisive Foramen, includes lateral

cleft lip, cleft upper jaw & cleft between 1ry & 2ry palates,
unilateral (C), bilateral (D)
b) Posteriorly: Behind incisive F, includes cleft of 2ry palate
& cleft uvula (E)
c) Antero-posteriorly: Combination, oblique/median (F)

Cleft lip


Unilateral cleft lip
and palate


Bilateral cleft lip
and palate


Unilateral cleft lip
and palate

Bilateral cleft lip
and palate

Development
of

Pituitary gland

Development of the pituitary gland
The pituitary gland is derived from 2
ectodermal sources:
 Anterior Lobe : develops from the
ectoderm of the roof of stomodeum
( Rathke’s pouch ).
 Posterior Lobe: develops from the floor
of the diencephalon ( Infundibulum ).



Development of pituitary gland


Congenital anomalies of pituitary
gland
 Craniopharyngioma

Tumour formed from persistance of a
small portion of Rathk’s pouch in the
roof of the pharynx.


Thanks and best of luck


Development of the face, nose, palate

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