platysma

The platysma is a pharyngeal arch 2 muscle and a superficial facial muscle that participates in oral/pharyngeal behaviors and is innervated by the cervical branch of the facial nerve. It attaches to the mandible and it attaches to the skin of the head, neck, and thoracic region where it is found superficial to the clavicle. Burrows et al. (2011) argue that in hylobatids (and, presumably, other primates) the platysma in the region of the modiolus represents both the cervicale and myoides muscles.