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The obturator foramen is a narrow hole surrounded in part by the pubic bone and the base of the hip bone. When part of the abdominal wall pushes through the obturator foramen, it is called an obturator hernia. This type of hernia is extremely rare, very difficult to diagnose, and is most common in women older than 70 who have recently lost a significant amount of weight. Symptoms include nausea, vomiting, and possibly abdominal pain. Once diagnosed, an obturator hernia is treated with surgery to remove the hernia.
There are three progressive steps in the development of an obturator hernia. The first step is the seeping of some abdominal fat into the obturator foramen, producing a fat plug. A dimple then develops in the fat plug and migrates inward to form a sac which then entraps a portion of an internal organ, primarily the intestines. Treatment for an obturator hernia is surgery, typically using laparoscopy, to remove the hernia, and then sutures or a mesh patch are sometimes used to reduce the opening and prevent further herniation. If the bowels have been damaged, they may need to be repaired during the surgery.
Mortality rates for obturator hernias are often the highest of all the abdominal hernias because proper diagnosis is difficult and is often not made in time. This type of hernia is so rare that it is not typically considered by doctors when reviewing a case. It also cannot be felt during a physical exam, so CT scans are necessary to even see the problem. CT scans do not always reveal the obturator hernia, and the hernia will be missed on the images altogether. Obturator hernias are often misdiagnosed as a bowel obstruction due to the similarity of symptoms.
Two helpful tools for diagnosing an obturator hernia are the Howship-Romberg sign and the profile of the patient. The Howship-Romberg sign is a shooting pain in the thigh caused by the hernia pinching the obturator nerve during hip rotation. This sign, however, is not present in all obturator hernia cases. An obturator hernia is most often present in women older than 70 who have recently experienced sudden weight loss. Women are prone to obturator hernias because they have wider hips and therefore a larger obturator foramen, and sudden weight loss reduces the abdominal fat typically protecting the foramen, making this opening even larger and more apt to develop a hernia.