DEVELOPMENT OF TONGUE THYROID GLAND, FACE AND PALATE By Dr
Samina Anjum
Slide 2
PHARYNGEAL ARCHES
Slide 3
Slide 4
Slide 5
Slide 6
Taste Buds Anterior 2/3 tongue - Cranial nerve VII
Circumvallate papillae - Cranial nerve IX Posterior 1/3 tongue -
Cranial nerve IX Most posterior part & Epiglottis - Cranial
nerve X
Slide 7
TONGUE TIE
Slide 8
Development of Thyroid The thyroid gland is the first endocrine
gland to develop in embryo. It begins to form about 24 days after
fertilization It develops from a median endodermal thickening in
the floor of a primordial pharynx Thickening soon forms a small
outpouching called thyroid primordium
Slide 9
Cont. As the embryo and tongue grow, the developing thyroid
gland descends in the neck, passing ventral to the developing hyoid
bone and laryngeal cartilages For a short time the thyroid gland is
connected to the tongue by a narrow tube, the thyroglossal duct,
disappears later
Slide 10
Cont At first the thyroid primordium is hollow but it soon
becomes solid and divides into right and left lobes. The two lobes
are connected by the isthmus of the thyroid gland. Isthmus lies
anterior to the developing second and third tracheal rings.
Slide 11
Cont By seventh week it has reached its final site in the neck
The proximal opening of the thyroglossal duct persists as a small
pit in the tongue, the foramen cecum A pyramidal lobe extends
upward from the isthmus in about 50% of people The pyramidal lobe
and the associated smooth muscle represent a persistent part of the
distal end of the thyroglossal duct
Slide 12
Thyroglossal Duct Cysts & Sinuses Following infection of a
cyst, a perforation of the skin occurs forming a thyroglossal duct
sinus
Slide 13
Slide 14
Lingual Thyroid
Slide 15
DEVELOPMENT OF FACE STOMODIUM: Is the depression between five
elevations. Opposed to the primitive pharynx by buccopharyngeal
membrane, which will break down later, then stomodeum communicates
with the foregut.
Congenital malformations 1) cleft lip: a. unilateral cleft lip:
results from failure of the maxillary prominence to merge with
medial nasal prominence on the affected side
Slide 37
b. bilateral cleft lip : results from failure of the maxillary
prominences to merge with the medial nasal prominence on both sides
c. median cleft lip: results from failure of the medial nasal
prominences to merge and form the intermaxillary segments
Slide 38
2) oblique facial cleft: results from failure of the maxillary
prominence to fuse with the lateral nasal prominence