A cleft lip is a congenital condition where there is an opening or gap in the upper lip, usually between the mouth and the nose. It can appear as a small notch in the coloured part of the lip or as a wider separation that extends into one or both sides of the nose. If the cleft appears on one side only, it is called a unilateral cleft; if it affects both sides, it is known as a bilateral cleft. A cleft lip may also be accompanied by a cleft in the gum, ranging from a small notch to a complete separation into distinct parts. The "before" and "after surgery" photos below show a girl with a complete unilateral cleft lip and a partially cleft gum.