Cleft lip is the most common congenital facial defect due to incomplete fusion of the maxillary and medial nasal processes during embryonic development. Surgical repair is typically performed within the first 3 months of life to restore function and aesthetics. The key surgical principle is to achieve anatomic alignment of the orbicularis oris muscle to ensure normal lip movement and prevent distortion. Precise muscle repair also promotes optimal upper lip contour and nasal symmetry. Early intervention reduces feeding difficulties and supports speech development. Proper timing and technique are critical for minimizing scarring and secondary deformities.

Reference: Bailey & Love's Short Practice of Surgery, 27th Edition.