1. DEVELOPMENT OF FACE , NOSE AND PALATEBy
Prof.
Saeed Abuel Makarem
Prof. Makarem

2. Development The of Face
The facial primordia appear early in the fourth week around the primordial stomodeum FN MX MX md md S
Prof. Makarem

3. Five facial primordia appear as prominences around the stomodeum
The single frontonasal prominence
The paired maxillary prominences
The paired mandibular prominences
FNP
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4. The paired facial prominences are derivatives of the first pair of pharyngeal arches
The prominences are produced mainly by the proliferation of neural crest cells.
These cells migrate from the Mesencephalon and & Rhombencephalon regions of the neural folds into the arches during the fourth week
1st
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5. The Nasal placodes:
Two bilateral oval thickenings in the surface ectoderm, of the frontonasal prominence, appear, by the end of the fourth week.
Nasal placodes are the primordia of the nose and nasal cavities.
Initially these placodes are
convex.
Later, they are stretched to produce a flat depression in each placode.
Prof. Makarem

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7. Now the nasal placodes lie in depression called nasal pits
Mesenchyme in the margins of the placodes proliferate, producing horse shoe shaped elevations called medial and lateral nasal prominences
Now the nasal placodes lie in depression called nasal pits
These pits are the primordia of the anterior nares (nostrils) and nasal cavities
Prof. Makarem

8. Mesenchymal cells are the major source of
the connective tissue components, including muscles, cartilage, bone, and ligaments in the facial and in the oral regions.
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9. The frontonasal prominence (FNP) is formed of 2 parts:
1- Frontal part: forms the forehead
2- Nasal part: forms the rostral boundary of the stomodeum.
The paired maxillary prominences form the lateral boundaries of the stomodeum
The paired mandibular prominences constitute the caudal boundary of the primitive mouth
Prof. Makarem

10. Facial development occurs mainly between the fourth and eighth weeks.
By the end of the embryonic period, (8th week) the face has an unquestionabl human appearance.
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11. Between the 7th and 8th weeks, the two medial nasal prominences merge with each other and with the maxillary and lateral nasal prominences
Merging of the medial nasal and maxillary prominences results in continuity of the upper jaw and upper lip and separation of the nasal pits from the stomodeum
Prof. Makarem

12. The lower jaw and lower lips are the first parts of the face to form
They result from merging of the medial ends of the mandibular prominences in the median plane
Median cleft lower lip is a very rare condition M
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13. Each lateral nasal prominence is separated from the maxillary prominence by a cleft called nasolacrimal groove
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14. The nasolacrimal duct develops from a rodlike thickening of ectoderm in the floor of the nasolacrimal groove
This thickening gives rise to a solid epithelial cord that separates from the ectoderm and sinks into the mesenchyme
As a result of cell degeneration, this epithelial cord canalizes to form the nasolacrimal duct
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15. The cranial end of this duct expands to form the lacrimal sac
By the late fetal period, the nasolacrimal duct drains into the inferior meatus in the lateral wall of the nasal cavity
The duct usually becomes completely patent only after birth
Occasionally, part of the duct fails to canalize causing atresia of the nasolacrimal duct.
Prof. Makarem

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17. Development of the External Ear
By the end of the fifth week, the primordia of the auricles of the ears have begun to develop
Six auricular hillocks form around the first pharyngeal groove (cleft).
Three on each side of the 1st pharyngeal groove (cleft).
These are the primordia of the auricle and external acoustic meatus.
Initially the ear located in the neck.
As the mandible develops the ears ascend to the level of the eye.
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18. Development of The Palate
As the medial nasal prominences merge, they
form an intermaxillary segment
The intermaxillary segment gives rise to:
1- The Philtrum (median part of the upper lip).
2- The Premaxillary part of the maxilla and
associated gingiva (gum).
3- The primary palate.
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19. Development of Palate
The palate develops from two stages:
Primary palate
Secondary palate
Palatogenesis begins at the end of the fifth week and is completed at twelfth week ( 12 )
The critical period of the palate development is from the end of the sixth week until the beginning of ninth week (  9)
Prof. Makarem

20. Primary Palate
Early in the sixth week the primary palate or median palatine process begins to develop from the intermaxillary segment of the maxilla
Initially this segment is formed by merging of the medial nasal prominences
The primary palate forms the premaxillary part of the maxilla
It represents only a small part of the adult hard palate
(2 Medial nasal prominences >>>>intermaxillary segment .>>>>>>>>>-primary palate).
Prof. Makarem

22. Secondary Palate
The secondary palate is the primordium of the hard and soft palate
It begins to develop early in the sixth week from two mesenchymal projections that extend from the internal aspects of the maxillary prominences
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23. Initially the lateral palatine processes or palatal shelves project inferomedially on each side of the developing tongue
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25. Gradually these processes approach each other and
As the jaws develop, the tongue becomes relatively smaller and moves inferiorly
During the 7th & 8th weeks, the lateral palatine processes elongate and ascend to a horizontal position superior to the tongue
Gradually these processes approach each other and
fuse in the median plane
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26. Palatine processes also fuse with the nasal septum and the posterior part of the primary palate
The nasal septum develops as a downgrowth from internal parts of the merged medial nasal prominences
The fusion between the nasal septum and the palatine processes begins anteriorly during the ninth week and is completed posteriorly by the twelfth week
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28. Palatal shelves move medially and fuse with the nasal septum.
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29. The posterior part of these processes do not ossified.
Bone gradually develops in the primary palate, forming the premaxillary part of the maxilla, which lodges the incisor teeth
Concurrently bone extends from the maxillae and palatine bones into the lateral palatine processes to form the hard palate
The posterior part of these processes do not ossified.
Prof. Makarem

30. Its soft conical projection is called uvula
They extend posteriorly beyond the nasal septum and fuse to form the soft palate.
Its soft conical projection is called uvula
The median palatine raphe indicates the line of fusion of the lateral palatine processes
Prof. Makarem

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32. Cleft Lip and Palate
The defect is usually classified according to developmental criteria
There are two major groups of cleft lip and palate:
Clefts involving the upper lip and anterior part of the maxilla
Clefts involving the hard and soft regions of the palate
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