An internal abdominal herniation is the protrusion of an abdominal organ through a normal or abnormal mesenteric or peritoneal aperture . An internal abdominal herniation differs from both an external abdominal herniation, in which the protrusion occurs through an opening of the abdominal wall, and a diaphragmatic herniation, which involves a weakness of the diaphragm. Internal abdominal herniations can be either acquired through a trauma or surgical procedure (iatrogenic internal abdominal herniations) or constitutional and related to congenital peritoneal defects.
Because internal abdominal herniations are rare, their diagnosis remains a challenge for both the clinician and the radiologist. Symptoms of internal abdominal herniations are nonspecific, consisting of mild abdominal discomfort alternating with episodes of intense periumbilical pain and nausea. CT is believed to facilitate the diagnosis of internal abdominal herniations. Specific signs of internal abdominal herniations on CT have been previously reported [2–4]. The use of CT could limit the rate of misdiagnosed internal abdominal herniations because subtle transmesenteric internal abdominal herniations can be difficult to diagnose on laparoscopy.
This pictorial essay focuses on constitutional internal abdominal herniations (excluding iatrogenic and surgical internal herniations). We review the main mechanisms of internal abdominal herniations and the main radiologic findings on barium as well as CT studies.