ANATOMY

Detailed explanation-1: -Failure of the medial nasal prominences to fuse with the medial aspect of the maxillary process produces a cleft lip, among the most common congenital abnormalities of the head and neck. A complete cleft lip extends into the floor of the nose, whereas an incomplete cleft extends only partway through the upper lip.

Detailed explanation-2: -Very early in pregnancy, a developing fetus has a split lip and palate, but around seven weeks of gestational age, the sides of the lip and the roof of the mouth should fuse. Failure of fusion results in cleft lip and/or cleft palate.

Detailed explanation-3: -Cleft lips form as a result of failure of the medial nasal process to contact the maxillary process. Lip formation is set largely during weeks 4 to 7 of human development. Cleft palates typically develop from a failure of fusion of the opposing palatine processes of the paired maxillary prominences.

Detailed explanation-4: -Lateral facial clefts result from failure of the maxillary and mandibular processes to fuse. Median mandibular clefts result when the medial ends of the first pharyngeal arch fail to fuse, possibly because of abnormal growth centers at the arch’s medial tips.

Detailed explanation-5: -The medial nasal processes develop medial to the nasal placode and will eventually fuse at the midline to form the inter-maxillary process. By the tenth week, the inter-maxillary process will form the nasal bridge and the philtrum of the upper lip.