Click on the structure to specify the target of your label
Branchial arch muscles
The majority of muscles in the head and associated pharynx and larynx develop from the mesodermal arches of tissue that surround the front end of the developing embryonic gut tube. The arches arise in a segmental series that begins near the developing mouth and extends caudally around the pharynx towards the developing heart region of the embryo. Each embryonic arch is a serial homologue that consists of a skeletal bar that supports the arch, muscle that surrounds the skeletal support of the arch, branches of the aorta that supply blood to the tissues of the arch, and a single dorsal cranial nerve that innervates the tissues of the arch. As development proceeds, the structural relationships established in each embryonic arch are retained in the final adult body plan. That is, the muscles form common groups within common fascial boundaries that share common actions and the nerve of the arch innervates all the muscles from that arch. For example, the trigeminal nerve, the nerve of the first branchial arch, innervates all the muscles that develop from that arch. The same is true for the second arch, and the third arch, and etc. Understanding this and using this approach can greatly simplify learning and remembering the detailed muscle anatomy of the head.