19 Dev. of Face, Palate, Nose, Teeth

Question 1

The palatine tonsils are located between the anterior and posterior tonsillar pillars. Which muscles form these pillars?

Answer 1

The pillars are formed by the palatoglossal arch anteriorly and the palatopharyngeal arch posteriorly

Question 2

An infant will undergo reconstruction of a unilateral upper cleft lip. Failure of fusion of which structures caused this defect?

Answer 2

Cleft lip is a result of the failure of the mesenchyme in the medial nasal and maxillary prominences to fuse. Unilateral cleft occurs if the maxillary prominence on the affected side failes to fuse with the intermaxillary segment, whereas bilateral cleft occurs if there is failure of fusion on both sides.

Median cleft occurs from failure of formation of the intermaxillary segment from the medial nasal processes.

Question 3

An infant had a deformity of the face in which a groove connected the medial canthus of the right eye to the right corner of the upper lip. There was a clear, watery discharge from the groove. A defect in which developmental process most likely resulted in the deformity seen?

Answer 3

Oblique facial clefts occur when there is failure of fusion of the mesenchyme of the maxillary process with the lateral nasal process. The nasolacrimal ducts are open grooves draining the tears from the lacrimal gland that lubricate the conjunctiva.