In all vertebrates, the pharyngeal apparatus develops from a series of bulges found on the lateral surface of the head, the pharyngeal arches, which consist of a number of different embryonic cell types. Each arch has an external covering of ectoderm and inner covering of endoderm, and between these a mesenchymal filling of neural crest with a central core of mesoderm.[well established][VHOG]

uberon

4th branchial arch mesenchyme

pharyngeal arch 4 mesenchyme

UBERON:0005691