Obturator foramen

The obturator foramen is the hole created by the ischium and pubic bones of the pelvis through which nerves and muscles pass.


 * In the male it is large and of an oval form, its longest diameter slanting obliquely from before backward.
 * in the female it is smaller, and more triangular.

It is bounded by a thin, uneven margin, to which a strong membrane is attached, and presents, superiorly, a deep groove, the obturator groove, which runs from the pelvis obliquely medialward and downward.

This groove is converted into the obturator canal by a ligamentous band, a specialized part of the obturator membrane, attached to two tubercles:
 * one, the posterior obturator tubercle, on the medial border of the ischium, just in front of the acetabular notch
 * the other, the anterior obturator tubercle, on the obturator crest of the superior ramus of the pubis

Through the canal the obturator vessels and obturator nerve pass out of the pelvis.