Markowitz S K, Ziter F M
Ann Emerg Med. 1986 Apr;15(4):425-7. doi: 10.1016/s0196-0644(86)80180-9.
The erect posteroanterior chest film has long been considered the most sensitive for the detection of intraperitoneal free air. A review of 21 cases of pneumoperitoneum showed three with air present on the lateral but not on the frontal chest radiograph. An explanation for this finding is proposed. We believe that careful evaluation of the lateral chest radiograph for pneumoperitoneum will be helpful in certain cases.
