Obturator membrane is a thin fibrous sheet that almost completely closes the obturator foramen of hip bone, leaving only a small gap, the obturator canal, for the passage of obturator nerve and vessels.
The fibers of the obturator membrane are arranged mainly in transverse direction. The membrane is attached to the sharp margins of the obturator foramen. At its lower lateral angle, the membrane is fixed to the pelvic surface of the inferior ramus of ischium.
Obturator membrane provides attachment for both obturator internus and obturator externus.