Middle pharyngeal constrictor muscle

The middle pharyngeal constrictor is a fan-shaped muscle located in the neck. It is one of three pharyngeal constrictor muscles. It is smaller than the inferior pharyngeal constrictor muscle.

The middle pharyngeal constrictor originates from the greater cornu and lesser cornu of the hyoid bone, and the stylohyoid ligament. It inserts onto the pharyngeal raphe. It is innervated by a branch of the vagus nerve through the pharyngeal plexus. It acts to propel a bolus downwards along the pharynx towards the esophagus, facilitating swallowing.

Structure

The middle pharyngeal constrictor is a sheet-like, fan-shaped muscle.

The muscle's fibers diverge from their origin: the more inferior fibres descend deep to the inferior pharyngeal constrictor muscle; the middle portion of fibres pass transversely; the more superior fibers ascend and overlap the superior pharyngeal constrictor muscle.

Origin

Two parts of the middle pharyngeal constrictor muscle are distinguished according to its sites of origin:

• Ceratopharyngeal part - arises (the entire superior margin of) the greater cornu of the hyoid bone.
• Chondropharyngeal part - arises from the lesser cornu of the hyoid bone, and (the inferior portion of) the stylohyoid ligament. The chondropharyngeal part represents the muscle's anterior origin.

Insertion

The muscle inserts (posteriorly) into the pharyngeal raphe, blending with its contralateral partner at the midline.

Innervation

Similarly to the superior and inferior pharyngeal constrictor muscles, it is innervated by a branch of the vagus nerve through the pharyngeal plexus.

Actions/movements

The contraction of the muscle constricts the middle portion of the pharynx.

Function

The muscle contracts during swallowing: 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 towards the esophagus.

They also have respiratory mechanical effects.

Additional images

References

This article incorporates text in the public domain from page 1143 of the 20th edition of Gray's Anatomy (1918)

Further reading

• Its role in speech: Hamaker, Ronald C.; Blom, Eric D. (2003). "Botulinum Neurotoxin for Pharyngeal Constrictor Muscle Spasm in Tracheoesophageal Voice Restoration". The Laryngoscope. 113 (9): 1479–1482. doi:10.1097/00005537-200309000-00010. ISSN 0023-852X. PMID 12972919. S2CID 12251825.
• Its role in Hyoid bone syndrome: Ernest, Edwin A.; Salter, E. George (1991). "Hyoid bone syndrome: A degenerative injury of the middle pharyngeal constrictor muscle with photomicroscopic evidence of insertion tendinosis". The Journal of Prosthetic Dentistry. 66 (1): 78–83. doi:10.1016/0022-3913(91)90357-3. ISSN 0022-3913. PMID 1941681.

External links

• lesson8 at The Anatomy Lesson by Wesley Norman (Georgetown University) (latpharyngealitems3)