Origin: Cricoid and thyroid cartilage
Insertion: Pharyngeal raphe
Nerve: External laryngeal branch of thevagus
The Inferior constrictor (Constrictor pharyngis inferior) the thickest of the three constrictors, arises from the sides of the cricoid and thyroid cartilage. From the cricoid cartilage it arises in the interval between the Cricothyreoideus in front, and the articular facet for the inferior cornu of the thyroid cartilage behind. On the thyroid cartilage it arises from the oblique line on the side of the lamina, from the surface behind this nearly as far as the posterior border and from the inferior cornu. From these origins the fibers spread backward and medialward to be inserted with the muscle of the opposite side into the fibrous raphé in the posterior median line of the pharynx. The inferior fibers are horizontal and continuous with the circular fibers of the esophagus; the rest ascend, increasing in obliquity, and overlap the Constrictor medius.