Dysphagia produced by a contractile ring in the lower esophagus.
D003679:Deglutition; D003680:Deglutition Disorders / Q000209:etiology*; D004947:Esophagus / Q000002:abnormalities*; D006801:Humans
DEGLUTITION DISORDERS/etiology and pathogenesis; ESOPHAGUS/abnormalities