| Inferior pharyngeal constrictor muscle | |
|---|---|
| Muscles of the pharynx and cheek. (Constrictor pharyngis inferior visible at bottom left.) | |
| Muscles of the pharynx, viewed from behind, together with the associated vessels and nerves. (Inf. const. labeled at bottom center.) | |
| Latin | musculus constrictor pharyngis inferior |
| Gray's | subject #244 1142 |
| Origin | cricoid and thyroid cartilage |
| Insertion | pharyngeal raphe |
| Artery | |
| Nerve | Pharyngeal plexus of vagus nerve |
| Actions | Swallowing |
The Inferior pharyngeal constrictor, the thickest of the three constrictors, arises from the sides of the cricoid and thyroid cartilage. Similarly to the superior and middle pharyngeal constrictor muscles, it is innervated by the vagus nerve (cranial nerve X), specifically, by branches from the pharyngeal plexus and by neuronal branches from the recurrent laryngeal nerve.
Contents |
The muscle is composed of two parts. The first (and more superior) arising from the thyroid cartilage (thyropharyngeal part) and the second arising from the cricoid cartilage (cricopharyngeal part). [1]
From these origins the fibers spread backward and medialward to be inserted with the muscle of the opposite side into the fibrous pharyngeal raphe 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.
As soon as the bolus of food is received in the pharynx, the elevator muscles relax, the pharynx descends, and the constrictors contract upon the bolus, and convey it downward into the esophagus.
Uncoordinated contraction, and/or Cricopharyngeal Spasm and/or impaired relaxation of this muscle are currently considered the main factors in development of a Zenker's diverticulum.
Motor incoordination of the cricopharyngeus can cause difficulty swallowing.
This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
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