pharyngeal arch pharyngeal arch 3 3 3rd arch 3rd pharyngeal arch 3rd visceral arch A conserved feature of all vertebrate embryos is the presence of a series of bulges on the lateral surface of the head, the pharyngeal arches; it is within these structures that the nerves, muscles and skeletal components of the pharyngeal apparatus are laid down. The pharyngeal arches are separated by endodermal outpocketings, the pharyngeal pouches.[well established][VHOG] AAO:0010365 EHDAA2:0000069 EHDAA:1080 EMAPA:16399 FMA:293029 TAO:0001598 The most anterior, or first, pharygeal/branchial arch, composed of the mandibular process, forming the posterior border of the stomodeum, and the maxillary process anterior to the stomodeum, contains the first aortic arch.[AAO] The third branchial arch contributes to the development of the hyoid bone, stylopharyngeus muscle, inferior parathyroid gland, and thymus. UBERON:0003114 VHOG:0000298 XAO:0000447 ZFA:0001606 branchial arch 1 first branchial arch first gill arch gill arch 1 in XAO, called branchial arch 1 and df VP3 third pharyngeal arch third visceral arch uberon visceral arch 3