Development of the face, nose, palate

Development ofDevelopment of

FaceFace NoseNose

palatepalate

Prof.Prof. Mohamed Mohamed AutifiAutifi

Development of the Development of the faceface

The face develops from 5 mesenchymal prominences (swellings or processes) that appear in the 4th week.

One Frontonasal prominence One Frontonasal prominence (formed by proliferation of mesenchyme and ectoderm ventral to the forebrain).

Two maxillary swellingsTwo maxillary swellings (from 1st pharyngeal arch).

Two mandibular swellings Two mandibular swellings (from 1st pharyngeal arch).

Prof. Mohamed AutifiProf. Mohamed Autifi

Development of the Development of the faceface 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 4th week, i.e. the 2 parts continue together.


Lips & gingivaeLips & gingivae::

They develop as a linear ectodermal

thickeningsaround the stomodeum labiogingival

laminae.They grow into mesenchyme, then degenerateforming labiogingival grooves separating lipsfrom gingivae.

A small area of laminae persists in median plane

forming frenulum of the lip.Prof. Mohamed AutifiProf. Mohamed Autifi

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.Prof. Mohamed AutifiProf. Mohamed Autifi

I. Frontonasal I. Frontonasal processprocess

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. Forehaed2. Middle of the nose and

nasal septum3. Filtrum of the upper lip4. Premaxilla Prof. Mohamed AutifiProf. Mohamed Autifi

II. Maxillary processesII. 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.


II. Maxillary processesII. Maxillary processes

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.


II. Maxillary processesII. Maxillary processes

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 Fate of maxillary processesprocesses

1. Cheeks2. Upper lip except the filtrum3. Palate except the premaxilla

Frnotnasal process


III. The mandibular III. The mandibular processesprocesses

Develop from the mesenchyme of the 1st pharyngeal arch.

Fate : Fate :

1. Lower jaw2. Lower lip3. Floor of the mouth


Development Development Of Of

Nasal cavitiesNasal 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 cavityDevelopment of Nasal cavity

28 day28 day



5 wk5 wk 6 wk6 wk



7 wk7 wk 12 wk12 wk


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.

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.


Development Development Of Of

PalatePalate


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


Congenital anomaliesCongenital anomalies

1. Anomalies of the mouth : Microstomia : small mouth opening Macrostomia : large mouth opening Agnathia : absence lower jaw Micrognathia : small lower jaw Anodontia : absence of the teeth

2. Anomalies of the nose : Stenosis of nostrils Deviation of the nasal septum


Macrostomia

Microstomia and single nostril

3. Anomalies of the face and palate :

1.Fusion dermoid: Cystic swelling developed alongline 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

Prof. Mohamed A. AutifiProf. Mohamed A. Autifi

Median cleft of the lower lip

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) Prof. Mohamed AutifiProf. Mohamed Autifi

Cleft lip


Unilateral cleft lip Unilateral cleft lip and palateand palate


Prof. Mohamed A. AutifiProf. Mohamed A. Autifi

Bilateral cleft lip Bilateral cleft lip and palateand palate


Unilateral cleft lip Unilateral cleft lip and palateand palate

Bilateral cleft lip Bilateral cleft lip and palateand palate


Development of

Pituitary glandPituitary gland

Development of the pituitary Development of the pituitary glandgland

The pituitary gland is derived from 2 ectodermal sources:

Anterior Lobe : Anterior Lobe : develops from the ectoderm of the roof of stomodeum stomodeum

( Rathke’s pouch ).( Rathke’s pouch ). Posterior Lobe: Posterior Lobe: develops from the

floor of the diencephalon ( Infundibulum ).( Infundibulum ).


Development of pituitary glandDevelopment of pituitary gland


Congenital anomalies of pituitary Congenital anomalies of pituitary glandgland

CraniopharyngiomaCraniopharyngioma

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


Thanks and best of Thanks and best of luckluck

Prof. Mohamed Prof. Mohamed AutifiAutifi

Development of the face, nose, palate

Health & Medicine

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