The upper esophageal sphincter area.

The localization of the upper esophageal sphincter is partly controversial. The aim of the present study was to elucidate whether or not the sphincter area could be allocated within an area inferior to and separate from the cricopharyngeal muscle. Cineradiography of the pharyngo-esophageal segment in 252 dysphagial patients disclosed a posterior impression in 55 (22%). There were no signs of a circular impression or other indications of a sphincter localized inferior to the circopharyngeus as revealed on these cinefilms. Macro- and microscopic examination of 16 autopsy specimens revealed the level of the upper esophageal sphincter to be localized within the cricopharyngeal muscle. There was no indication of any sphincter inferior to the cricopharyngeus in the cervical esophagus.