You assist to deliver a full term baby boy who is otherwise normal but
has a left cleft of the upper lip that extends upward toward the left
nostril and left anterior cleft of the primary palate just deep to the
cleft lip. These defects are most likely due to a failure of which of
the following?
A. Mandibular process to fuse with the lateral nasal process
B. Mandibular process to fuse with the medial nasal process
C. Maxillary process to fuse the lateral nasal process
D. Maxillary process to fuse the medial nasal process
A. Mandibular process to fuse with the lateral nasal process
B. Mandibular process to fuse with the medial nasal process
C. Maxillary process to fuse the lateral nasal process
D. Maxillary process to fuse the medial nasal process
Ans. D.
The lateral nasal process forms the alar
region of the nose. Normally the maxillary
process moves medially and fuses with the medial nasal process at the philtrum
on both sides of the upper lip. The fact that the cleft involves both the lip
and bony primary palate suggests failure of the maxillary process to fuse with
the medial nasal process. The mandibular process does not normally fuse with
either the lateral or medial nasal processes. That would reduce the size of the
mouth. The lateral and medial nasal processes fuse to form a nostril separate
from the oral cavity
