obturator foramen n.
A large oval or irregularly triangular aperture in the hipbone.
The obturator foramen is a small oval opening posteroventral to the acetabulum between the ischium and the pubis.
The larger ventral part arises directly from the anterior and ventral edges of the obturator foramen.
The acetabulum is deep and the obturator foramen large, and there is frequently a well-marked ischial tuberosity.
The dorsal part arises directly from the ischium along the dorsal edge of the obturator foramen.