Obturator externus is one of the muscles of the gluteal region. It arises from the:
- medial, external surface of the obturator membrane
- ramus of pubis
- ramus of ischium
The muscle fibres converge and pass posterolaterally to form a tendon. The tendon passes posterior to the neck of the femur and the inferior part of the capsule. It inserts into the trochanteric fossa on the medial aspect of the greater trochanter of the femur. Usually, there is a bursa interposed between the tendon and the femoral capsule.
It is innervated by the posterior branch of the obturator nerve (L2-4) which traverses the muscle.
Obturator externus acts to laterally rotate the hip joint.