Esophageal Sphincter, Lower

**Definition:** The physiologic or functional barrier to GASTROESOPHAGEAL REFLUX at the esophagogastric junction. Sphincteric muscles remain tonically contracted during the resting state and form the high-pressure zone separating the lumen of the ESOPHAGUS from that of the STOMACH. (Haubrich et al, Bockus Gastroenterology, 5th ed., pp399, 415)

**Tree numbers:** - A02.633.570.210 - A03.556.875.500.414.350 - A03.556.875.875.330.350

**Synonyms:** - Gastroesophageal Sphincter - Lower Esophageal Sphincter