Figure 1: CT pelvis at the hip joint level, indicating the obturator hernia (white arrows) of small bowel content passing through the obturator foramen into the thigh with gas formation in the muscles of the thigh (white arrow heads).

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Figure 2: Annotated CT abdomen and pelvis showing herniation of the small bowel and content through the obturator foramen (white arrows) and gas formation due to infection and gangrene in the muscles of the thigh (white arrow heads).

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An Obturator Hernia, or pelvic hernia is a rare hernia that occurs when part of the small bowel passes through the obturator foramen, along the path of the obturator nerve and muscles. The incidence of obturator hernia is less than 1% with a female to male ratio of 6:1, because of a gender-specific larger obturator canal diameter and occurred in predominantly in the (emaciated) elderly women.


Because of its anatomic position deep in the pelvis, obturator hernia tends to present as intestinal obstruction rather than protrusion of intestinal contents. Patients then to present with a complaint of deep seated hip, thigh or knee pain and may experience symptoms of loss of appetite, nausea and vomiting with signs of bowel obstruction such as abdominal distension and abdominal colicky pain. Diagnosis of a pelvic hernia is often made by eliciting the Howship-Romberg sign, a pain down the leg when the hip is extended.


Radiological imaging using CT scan as is with the case above is the gold standard for making a diagnosis of obturator hernia. Emergency laparotomy and reduction of the incarcerated bowel with excision of infracted bowel is the treatment of choice in order to safe lives. Delayed presentation and diagnosis can lead to bowel infarction with gangrene and gas formation in the deep muscles as indicated by the white arrow heads in the case presented above. Delayed surgical intervention contributed to a relatively high morbidity and mortality rate. Once the incarcerated bowel is reduced, the obturator foramen is closed or repaired using sutures.


Images and text contributed and prepared by

Mr Chee Fui Chong, Department of Surgery.

All images are copyrighted and property of RIPAS Hospital.