Inferior pharyngeal constrictor muscle
Inferior pharyngeal constrictor muscle | |
---|---|
Details | |
Origin | cricoid cartilage and thyroid cartilage |
Insertion | pharyngeal raphe |
Nerve | pharyngeal plexus of vagus nerve, recurrent laryngeal nerve and superior laryngeal nerve |
Actions | swallowing |
Identifiers | |
Latin | musculus constrictor pharyngis inferior |
TA98 | A05.3.01.111 |
TA2 | 2187 |
FMA | 46623 |
Anatomical terms of muscle |
The inferior pharyngeal constrictor muscle is a skeletal muscle of the neck. It is the thickest of the three outer pharyngeal muscles. It arises from the sides of the cricoid cartilage and the thyroid cartilage. It is supplied by the vagus nerve (CN X). It is active during swallowing, and partially during breathing and speech. It may be affected by Zenker's diverticulum.
Structure
The inferior pharyngeal constrictor muscle is composed of two parts. The first part (and more superior) arises from the thyroid cartilage (thyropharyngeal part), and the second part arises from the cricoid cartilage (cricopharyngeal part).[1]
- On the thyroid cartilage, it arises from the inferior horn of the thyroid cartilage.
- From the cricoid cartilage, it arises in the interval between the cricothyroid muscle in front, and the articular facet for the inferior horn of the thyroid cartilage behind.
From these origins, the fibers spread backward and medially to insert with the muscle of the opposite side into the fibrous
The inferior fibers are horizontal and continuous with the circular fibers of the
Nerve supply
The inferior pharyngeal constrictor muscle can be supplied by branches from the pharyngeal plexus,[4] the recurrent laryngeal nerve, the external branch of the superior laryngeal nerve, or a combination of these (the recurrent laryngeal nerve being the most common innervation of the cricopharyngeal part).[5] All these branches and nerves come from the vagus nerve (CN X).[4]
Variation
The inferior pharyngeal constrictor muscle can merge with superior pharyngeal constrictor, or posterior part of pharyngobasilar fascia.[6]
Function
The inferior pharyngeal constrictor muscle has a broad role in moving the lower part of the pharynx.[7]
Swallowing
As soon as a bolus of food is received in the pharynx, elevator muscles relax, and the pharynx descends. The inferior pharyngeal constrictor muscle, along with the other constrictors, contract upon the bolus, and convey it downward into the esophagus.[4][7] During swallowing, they contract and cause peristalsis in the pharynx.[4]
Breathing
The inferior pharyngeal constrictor muscle is partially used during breathing and speech.[4] It helps to keep the pharynx open, particularly during sleep.[8]
Clinical significance
Zenker's diverticulum
Uncoordinated muscle contraction, cricopharyngeal spasm, or impaired relaxation of the inferior pharyngeal constrictor muscle are currently considered the main factors in development of a Zenker's diverticulum. Zenker's diverticulum develops between the two muscular bellies (the thyropharyngeal part and the cricopharyngeal part) in a small gap called Killian's dehiscence. A diverticulum can form where a balloon of mucosa becomes trapped outside the pharyngeal boundaries. Food or other materials may reside here, which may lead to infection. Motor incoordination of the cricopharyngeal part can cause difficulty swallowing.
In extreme cases, this can be related to
Radiological damage
The inferior pharyngeal constrictor muscle may be damaged by chemotherapy-intensity modulated radiotherapy.[11] This may lead to dysphagia, causing continued use of a feeding tube rather than independent swallowing.[11]
Additional images
-
Muscles of the neck. Lateral view.
-
Side view of the larynx, showing muscular attachments.
-
Inferior pharyngeal constrictor muscle
-
Deep dissection of larynx, pharynx and tongue seen from behind
See also
- Upper esophageal sphincter
References
This article incorporates text in the public domain from page 1142 of the 20th edition of Gray's Anatomy (1918)
- ^ Origin, insertion and nerve supply of the muscle at Loyola University Chicago Stritch School of Medicine
- PMID 9583798.
- PMID 10687945.)
{{cite journal}}
: CS1 maint: multiple names: authors list (link - ^ S2CID 22153114.
- PMID 26843022.
- PMID 31869118, retrieved 2022-07-22
- ^ S2CID 44633854.
- S2CID 7751627.
- PMID 32328538.
- PMID 31236539.
- ^ PMID 24440043.
External links
- lesson8 at The Anatomy Lesson by Wesley Norman (Georgetown University) (latpharyngealitems3)