Development of the Face
Dr.Dashrath Kafle
FaceAt the end of the 4th week, facial prominences consisting
primarily of neural crest-derived mesenchyme appearMaxillary prominences- lateral to the stomodeum mandibular prominences- caudal to stomodeum
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Face contd...Frontonasal prominence - proliferation of mesenchyme
ventral to the brain vesicles
On both sides, local thickenings of the surface ectoderm, the nasal placodes originate
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Face contd...During the 5th week, the nasal placodes invaginate to
form nasal pits
Lateral nasal prominences
Medial nasal prominences
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Face contd...
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Formation of lipThe maxillary prominences grow medially,
compressing medial nasal prominences towards midline, two fuse forming upper lip by two medial nasal prominences and two maxillary prominences
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Development of noseMaxillary prominences enlarge to form the cheeks and
maxillaNose is formed from five facial prominences:
- frontal prominence gives rise to bridge
- merged medial nasal prominences provide the crest and tip
- lateral nasal prominences form the alae
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Intermaxillary SegmentTwo medial nasal prominences merge at a deeper level
forming the intermaxillary segment Composed of
(a) philtrum of the upper lip
(b) upper jaw component- carries the four incisor teeth
(c) primary palate
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Intermaxillary Segment contd...
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Secondary PalateFormed by two palatine shelves (6th week of
development) –maxillary processDirected obliquely downward on each side of the tongue In the 7th week, the palatine shelves ascend to attain a
horizontal position above the tongue and fuse, forming the secondary palate
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Secondary Palate contd...
Nasal septum: derivative of Frontonasal process
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Secondary Palate contd...Anteriorly, the palatine shelves fuse with the primary
palate
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Development of TongueAppear at 4 weeks As two lateral lingual swellings and one medial swelling,
the tuberculum impar (all originate from the first pharyngeal arch)
A second median swelling, the copula, formed by mesoderm of the second, third, and part of the fourth arch
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Tongue contd...
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Tongue contd...Lateral lingual swellings increase in size, overgrow the
tuberculum impar and merge, forming the anterior two-thirds, or body, of the tongue
The body of the tongue is separated from the posterior third by a V-shaped groove, the terminal sulcus
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Tongue contd...A third median swelling, formed by the posterior part of
the fourth arch, marks development of the epiglottis
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Development contd....
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Tongue contd...The mucosa covering the body of the tongue originates
from the first pharyngeal arch Sensory innervation to the posterior part, or root part of
the tongue is supplied by the glossopharyngeal nerve
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Tongue contd...The epiglottis and the extreme posterior part of the tongue
are innervated by the superior laryngeal nerve, reflecting their development from the fourth arch
Most tongue muscles are derived from myoblasts originating in occipital somites. So innervated by the hypoglossal nerve
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Tongue contd...Special sensory innervation (taste) to the anterior two
thirds of the tongue is provided by the chorda tympani branch of the facial nerve, while the posterior third is supplied by the glossopharyngeal nerve
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Development contd.......
•Circumvallate papilla- 2-5 months• Fungiform - 11 weeks•Filliform – after birth•Gustatory cells- starts 7th week•All taste bud present at birth except- taste bud (circumvallate papilla)