The nutcracker and the ostrich.
Castell
D O
DO
D002637:Chest Pain / Q000209:etiology; D015154:Esophageal Motility Disorders / Q000266:history; D004947:Esophagus / Q000503:physiopathology*; D049672:History, 19th Century; D006801:Humans; D010528:Peristalsis