ABSTRACT
Cleft lip (CL) is a defect of the primary palate resulting from the abnormal fusion of the maxillary and medial nasal processes. The lip is more commonly cleft on the left than on the right or bilaterally (6:3:1). Cleft lip, with or without an associated cleft palate (CL/P), is a different disease from the isolated cleft palate (CP), which is therefore described separately.
