Inferior pharyngeal constrictor muscle

The inferior pharyngeal constrictor muscle is one of the pharyngeal constrictor muscles. It has a sphincteric function, and physiologically is usually in a tonic state, constricting the distal end of the pharynx (in coordination with the superior pharyngeal constrictor and the middle pharyngeal constrictor muscles), only relaxing when a bolus of food passes into the esophagus as part of deglutition.

The muscle is described as having two main parts, thyropharyngeus and cricopharyngeus, which originate from the oblique line of the thyroid lamina and lateral aspect of cricoid cartilage respectively.

A focal weakness or deficiency between the plane of these two parts is termed a Killian dehiscence and can produce a pulsion-pseudodiverticulum, known as a pharyngeal pouch (Zenker diverticulum).

Summary

• origin: cricoid and thyroid cartilage
• insertion: pharyngeal raphe
• artery: ascending pharyngeal artery, branch of the external carotid artery
• nerve: pharyngeal plexus; cricopharyngeus part can also receive innervation from the recurrent laryngeal nerve and/or the external laryngeal nerve
• action: swallowing