This document provides an overview of cleft lip and palate, including:
- The incidence of cleft lip and palate is approximately 1 in 600 births worldwide. It is the second most common birth defect.
- The embryology of facial development and how failures in processes like fusion of the medial nasal processes can result in clefting.
- Cleft lip and palate have multifactorial etiology involving both genetic and environmental factors. Risk is increased with positive family history or exposure to teratogens.
- Classification systems have evolved over time but still categorize clefts as involving the lip, palate, or both, and as unilateral or bilateral. The Victor Veau system from 1931 remains influential