Cleft lip is a congenital deformity caused by a failure in facial development during pregnancy. It can be treated with surgery early upon birth with highly successful results. Cleft lip occurs in somewhere between one in 600 and one in 800 births.
It was previously called hare-lip (because a hare's lip is similarly cleft), or even hair lip (mis-spelling of the previous).
Cleft lip is closely related to the condition of cleft palate, and the two often occur together.
See also:
- Van der Woude syndrome
