The ileal flange: an anatomical landmark.

The abdominal surgeon is largely unappreciative of the peritoneal reflections of the ileocaecal region. This is not surprising since the literature on this subject is sparse. The available descriptions in standard texts (Hollinshead, 1971; McMinn, 1994; Williams et al. 1995) outline the appendicular mesentery as developing from the lowest aspect of the ileal mesentery. The inferior ileocaecal recess develops between the mesentery of the appendix and the ileocaecal fold; the superior ileocaecal recess develops between the ileal mesentery and the vascular fold of the caecum. The clinical significance of these recesses is minimal as they neither predispose to entrapment of bowel nor serve as useful landmarks. In this context, the peritoneal flange on the anti-mesenteric aspect of the terminal ileum warrants consideration (Fig. 1). This extension of the ileocaecal fold along a variable distance on the antimesenteric terminal ileum is largely underappreciated as it may hold value as a useful landmark to the abdominal surgeon.