Obturator externus

The obturator externus (Latin: musculus obturatorius externus) is a triangular-shaped muscle that is located deep within the pelvis. It stretches between the hip bone and femur. The obturator externus provides lateral (external) rotation of the thigh. Therefore, it is classified as the lateral rotator.

Origin

The obturator externus muscle originates from the external surface of the obturator membrane and the boundaries of the obturator foramen.

Insertion

The obturator externus inserts on the trochanteric fossa of the femur.

Action

The obturator externus muscle provides external (lateral) rotation of the thigh at the hip joint. Also, it stabilizes the hip joint.

Innervation

The obturator externus is innervated by the obturator nerve (L2 - L4) that arises from the lumbar plexus.

Blood supply

The obturator externus muscle receives arterial blood supply from the medial circumflex femoral and obturator arteries. The first artery is a branch of the deep femoral artery, while the latter arises from the internal iliac artery.