Cleft Palate occurs during which week of gestation?

# Cleft palate occurs in the ___________ of embryonic life.
A. First to third week
B. Fourth to sixth week
C. Eighth to tenth week
D. Twelfth to fourteenth week

The correct answer is C. 8th to 10th week.

Cleft palate occurs in the eighth to tenth week of embryonic life. Isolated clefts of the palate are more common in females. It is characterized by a fissure in the midline of the palate, resulting from the failure of the two sides to fuse during embryonic development.

The most severe handicap imposed by cleft palate is an impaired mechanism preventing normal speech and swallowing. 

Note: It affects approximately 1 in 2000 births.

Cleft lip results when the medial nasal process fails to fuse with the lateral portions of the maxillary process of the first branchial arch. Fusion normally occurs during the sixth and seventh weeks of embryonic development. The maxillary lip is most commonly affected.

It may be bilateral (20%) or unilateral (80%). Clefts of the lip are more frequent in males. Lip cleft involvement is more frequent on the left side than the right.

Note: It affects approximately 1 in 1000 births, but varies with race.