Cleft lip can be broadly classified as unilateral (on
one side of the lip) or bilateral (on two sides of the lip) and complete
(extends to the nose) or incomplete (does not extend to the nose). Most clefts
involve only one side of the upper lip; they rarely occur in the lower lip. The
different combinations of cleft lip include:
- A unilateral incomplete cleft, which is on only one side of the lip and does not extend to the
nose.
- A unilateral complete cleft, which is
on only one side of the lip and extends to the nose.
- A bilateral incomplete cleft, which occurs on both sides of
the lip but does not extend to the nose.
- A bilateral complete cleft, which occurs on both sides of the lip and
extends to the nose.
A unilateral cleft lip may cause the nostril on that side to be
tilted and lower than the other nostril, and a bilateral cleft lip may cause
the nose to be broader and shorter than normal.
See an illustration of different types of
cleft lip 
. Also see an illustration of a
cleft palate , which often occurs along with a cleft lip.
