Oropharyngeal isthmus

Last revised by Daniel J Bell on 21 Jan 2022

The oropharyngeal isthmus, a.k.a. isthmus of fauces, is the relative constriction of the anterior oropharynx that borders the oral cavity. The isthmus is sometimes described as the passage that transitions between the oral cavity and pharynx, but strictly speaking, it is part of the oropharynx.

Gross anatomy

The oropharyngeal isthmus is the short region delineated anteriorly and posteriorly by the palatoglossus and palatopharyngeus muscles 1. The palatoglossal and palatopharyngeal arches are also known, respectively, as the anterior and posterior pillars of the fauces. To either side of the oropharyngeal isthmus sit the palatine tonsils, also known as the faucial tonsils. The soft palate, superiorly, and base of the tongue, inferiorly, constrict this portion of the aerodigestive tract.

History and etymology

The etymology of fauces is Latin, meaning throat. The word is rarely used in its singular form, faux, which is not attested in classical Latin 2.

The term oropharyngeal isthmus was intended to replace the older isthmus faucium (isthmus of fauces) 3, but they are listed synonymously in the current Terminologia Anatomica.

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