[Radiological diagnosis of the perforations of the stomach and the duodenum--special consideration on the meaning of the free air sign (author's transl)].
D004386:Duodenum / Q000000981:diagnostic imaging*; D006801:Humans; D007416:Intestinal Perforation / Q000000981:diagnostic imaging*; D010439:Peptic Ulcer Perforation / Q000000981:diagnostic imaging*; D011859:Radiography; D013270:Stomach / Q000000981:diagnostic imaging*