T5: Embryology and its Clinical Relevance

Question 1

A Unilateral cleft lip is resulted from the failure of what?

Answer 1

Maxilary Prominence and the medial nasal prominence ( inter maxillary segment)

Question 2

An internal brachial sinus opens where?

Answer 2

into the tonsillar fossa

Question 3

A boy reports to the clinic with a opening on the side of his neck externally & in the tonsillar sinus internally. What is the malformation that causes this clinical feature?

A. Persistence of the cervical sinus & 2nd pharyngeal groove
B. Failure of formation of the 1st arch
C. Cystic Remnant of the thyroglossal duct
D. Persistence of the 2nd groove and 2nd Pouch
E. Failure of neural crest cells to the 3 & 4 arch
F. Failure of maxillary prominence to fuse with merged medial nasal prominences

RFA

Answer 3

ANS. D. The Boy has a Brachial Fistula and this is caused by Persistence of the 2nd groove & 2nd Pouch

A. Persistence of the cervical sinus and 2nd pharyngeal groove= Brachial Cysts

B. Failure of formation of the 1st arch= Treacher Collins & Pierre Robin

C. Cystic Remnant of the thyroglossal duct= Thyroglossal cyst

E. Failure of neural crest cell to the 3rd and 4th arch= Digeorge

F. Failure of maxillary prominence to fuse with merged medial nasal prominences= Cleft Lip