Description: The obtruator externus m. is a fan-shaped, deeply placed m. in the supromedial part of the thigh, external to the true pelvis. It attaches to the margins of the obturator foramen and its' membrane, inserting on the trochanteric fossa of the femur posteriorly. Circulation is via the internal iliac a., and innervation is from L3-L4 by the obturator a.