Lower esophageal ring.
D003680:Deglutition Disorders / Q000209:etiology; D004940:Esophageal Stenosis / Q000150:complications; D004947:Esophagus; D005764:Gastroesophageal Reflux / Q000150:complications; D006551:Hernia, Hiatal / Q000150:complications; D006801:Humans