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Upper esophageal sphincter: Wikis


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Upper esophageal sphincter
Muscles of the pharynx and cheek. (Constrictor pharyngis inferior visible at bottom left.)
Sagittal section of nose mouth, pharynx, and larynx. (Upper esophageal sphincter not labeled, but region is visible.)
MeSH Upper+Esophageal+Sphincter

The upper esophageal sphincter (UES) (also called the Pharyngoesophageal sphincter) refers to the superior portion of the esophagus.

Unlike the lower esophageal sphincter, it consists of striated muscle and is under conscious control. The primary muscle of the UES is the cricopharyngeus portion of the inferior pharyngeal constrictor. [1]

During swallowing the upper esophageal sphincter opens so the bolus can pass into the esophagus. A secondary role of the UES is to reduce backflow from the esophagus into the pharynx.


  1. ^ Mu L, Wang J, Su H, Sanders I (2007). "Adult human upper esophageal sphincter contains specialized muscle fibers expressing unusual myosin heavy chain isoforms". J. Histochem. Cytochem. 55 (3): 199–207. doi:10.1369/jhc.6A7084.2006. PMID 17074861.  

See also

Lower esophageal sphincter

External links

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 As such, some of the information contained within it may be outdated.



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