What is cleft?
Cleft describes the most common facial deformity: the lip and palate cleft, popularly called "harelip".
The lip and palate clefts are in fact two different developmental disorders (lip clefts and palate clefts) which have in common that between the fourth to eight week of pregnancy parts of the mouth do not develop normally. During this time usually the respective paired lateral structure of the lip and palate join to form the upper lip and the soft and hard palate. If these parts do not join the consequence are visible defects respectively clefts. Depending on when the disorder developed during pregnancy and how stressful this was, different forms exist. These may affect just the lips (lip cleft) or the soft palate (palate cleft), but in combination also the lips, the whole jaw (lip and palate cleft) and the face (facial cleft).