Facial skeleton develops from ?

Ans. is 'a' i.e., Neural crestViscerocranium or bones of face are formed from mesenchyme derived from neural crest present in 1" and 2nd pharyngeal arches.Development of face Facial development occurs mainly between 4th and 8th weeks, and is induced by migration of cells of neural crest. Five facial primordia appear as prominences of mesenchyme : a frontonasal process, a pair of maxillary processes and a pair of mandibular processes.Frontonasal process is divided into :-Lateral nasal processes : From alae of nose.Medial nasal processes : These merge with each other to form intermaxillary segemnt which gives rise to : (a) philtrum (middle pa of upper lip), (b) premaxillary plate.Formation of various facial structures Component Develops from Upper lip Philthrum (middle pa) : From intermaxillary segment (fused medial nasal processes) of frontonasal process. Lateral pas : From maxillary processes. Lower lip From mandibular processes. Upper jaw From maxillary processes except for premaxilla (carries four incisors) which develop from intermaxillary segment of frontonasal process. Lower jaw From mandibular processes. Cheeks By fusion of maxillary process with mandibular process on each side. Nosolacrimal duct Canalization of ectodermal ridge formed by fusion of lateral nasal process with maxillary process. Eye ball and orbit Optic vesicle and surface ectoderm and mesoderm on either side of frontonasal process.