| first duodenal sphincter | The sphincter supposedly located at the level of the aboral extremity of the duodenal bulb. (05 Mar 2000) |
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| lower oesophageal sphincter | <anatomy> A muscular sphincter located at the junction of the oesophagus and the stomach. On closure the lower oesophageal sphincter prevents the back wash (reflux) of stomach acid into the oesophagus where it may damage the mucosa. See: gastrooesophageal reflux disease. (16 Mar 1998) |