Answer:
Cleft lip deformities vary significantly from incomplete to complete unilateral or bilateral clefts. The cleft lip has a shortened philtral height. The orbicularis oris muscle on the lateral portion of the lip inserts onto the alar wing, whereas in the medial region, the muscle inserts onto the columella. In cases of incomplete clefting, the muscles do not cross the cleft unless the bridge is at least 1/3 the height of the lip. The premaxilla projects beyond the noncleft side and rotates outward. The nasal structures are also involved to varying degrees. The inferior edge of the septum is dislocated out of the vomerine groove into the floor of the normal nostril. The lateral alar base is invariably rotated outward and flares laterally. The alar rim is distorted by the overlying skin. The hemicolumella on the cleft side is foreshortened. The vestibular lining on the cleft side is deficient. The lower lateral cartilage is attenuated with the medial crus located lower in the columella. The dome is separated from the opposite alar cartilage. The lateral segment of the dome cartilage is flattened and extends obliquely across the cleft at an angle. The severity of these deformities is related to the extent of the cleft.