Pharyngeal Arch

**Semantic type:** Embryonic Structure

**Definition:** One of a series of paired mesodermal tissue bands located on either side of the embryonic pharyngeal foregut, composed of an ectodermal covering, and endodermal lining, and a mesenchymal core, that contains an arch artery, a cranial nerve, a cartilaginous rod and a muscular component. Each arch differentiates to form different components of the head and neck.