Air in the esophagus: a frequent radiographic finding.

While the radiologic literature discusses the presence of air in the esophagus on chest radiographs, this has almost always been reported as a finding associated with other radiologic abnormalities. In a retrospective study, esophageal air was noted on 36% of normal posteroanterior chest radiographs. The radiologic anatomy of the esophagus and the typical locations of air within it are discussed.