cricopharyngeus muscle
The cricopharyngeus is a pharyngeal arch 4/6 muscle that participates in oral/pharyngeal behaviors and is innervated by the pharyngeal plexus and the recurrent laryngeal n. (from Vagus, CN X), and is an integral part of the pharyngeal tube, and attaches to the cricoid cartilage and the midline raphe. It acts as a sphincter between the pharynx and esophagus.