Craniofacial development is a multistep and intricate process initially involving a number of inductive interactions that control neural and neural crest development, which are followed by a series of epithelial-mesenchymal interactions that control outgrowth, patterning, and skeletal differentiation. Certain aspects of craniofacial development are unique developmental processes in higher vertebrates. First, in higher vertebrates the cranial neural crest, in contrast to the trunk neural crest, gives rise to the skeletal structures. These skeletal elements include those comprising mem- brane...