Five pairs of arched structures that form the lateral and ventral walls of the pharynx of the embryo. The first is the mandibular arch; the second is the hyoid arch; the third, fourth, and fifth arches are transitory. They are partially separated from each other externally by the branchial clefts and internally by the pharyngeal pouches. They are important in the formation of structures of the face and neck.

SYN: pharyngeal arches

Main entry:
arch