Plain film diagnosis of retrocecal appendicitis.

The plain radiographic findings encountered in 21 patients with acute retrocecal appendicitis were analyzed. In descending order of frequency, the following changes were noted: (a) edema infiltration of properitoneal fat; (b) mass between properitoneal fat and ascending colon; (c) a coprolith above the anterior superior iliac spine; (d) gas in the appendix; (e) haustral irregularity of the ascending colon; and (f) retrocecal extraperitoneal gas.