Plain film diagnosis of the acute abdomen.

Abdominal plain films are essential for accurate assessment of the acute abdomen. In many cases, they may confirm the presence of a perforated viscus, colonic obstruction, or other abnormality requiring immediate surgical intervention. Alternatively, they may suggest relatively benign disease and help avoid unnecessary operations in these patients. In either case, emergency room physicians should benefit greatly from a systematic approach to the plain film diagnosis of the acute abdomen.