Internal, or retroperitoneal, hernia is an unusual condition characterized by the protrusion of abdominal contents through a congenital, acquired or anomalous opening wholly within the abdomen. The vast majority of these internal hernias are also retroperitoneal, and they occur most frequently in the region of the duodenojejunal junction, about the cecum (pericecal retrocolic) and sigmoid colon. At these points rudimentary fossae are frequently found; when they attain sizable proportions, as they rarely do, they may contain abdominal viscera, and are then properly termed retroperitoneal hernias.
INCIDENCE OF RETROPERITONEAL HERNIA
Some conception of the infrequent occurrence of retroperitoneal hernia may be gathered from the fact that Short,1 in a survey of the literature in the decade between 1914 and 1924, was able to compile reports of only thirty-eight cases of retroperitoneal hernia of all kinds, including duodenal hernia, retrocolic or pericecal, hernia into the foramen of Winslow, intersigmoid hernia, hernia