obturator foramen

The obturator foramen is the large, obliquely oriented, ovoid aperture located at the anterior aspect of both sides of the pelvis, bounded by parts of the ischium and pubis. It is covered by thin fibrous membrane, the obturator membrane, which is covered on the internal and external surfaces by the muscles obturator internus and obturator externus respectively. At its superior margin, the membrane is devoid forming the obturator canal which allows the obturator nerve, artery and vein to exit the pelvis and enter the medial compartment of the thigh.

Gross anatomy

  • superior: superior pubic ramus and inferior margin of the acetabulum
  • anterior: pubic body
  • inferior: ischiopubic ramus (inferior pubic ramus)
  • posterior: ischiopubic ramus (inferior pubic ramus) and acetabulum


It is larger and more oval in males, whereas it is smaller and more triangular in females.

Clinical importance

Although uncommon, an obturator hernia can pass through the foramen and cause bowel obstruction.

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