Origin The internal obturator muscle arises from the inner surface of the antero-lateral wall of the
pelvis. It surrounds the
obturator foramen. It is attached to the
inferior pubic ramus and
ischium, and at the side to the inner surface of the
hip bone below and behind the
pelvic brim. The
pudendal nerve passes on the lateral surface of the internal obturator muscle and the
coccygeus muscle. The
sciatic nerve passes superficial to the internal obturator muscle on the posterior surface.
Insertion The tendon inserts on the
greater trochanter of the proximal
femur.
Nerve supply The internal obturator muscle is supplied by the
obturator internus nerve (
L5,
S1, and
S2).
Bursa/bands This bony surface is covered by smooth cartilage, which is separated from the tendon by a
bursa, and presents one or more ridges corresponding with the furrows between the tendinous bands. These bands leave the pelvis through the lesser sciatic foramen and unite into a single flattened tendon, which passes horizontally across the capsule of the hip-joint, and, after receiving the attachments of the
superior and
inferior gemellus muscles, is inserted into the forepart of the medial surface of the greater trochanter above the
trochanteric fossa. A bursa, narrow and elongated in form, is usually found between the tendon and the capsule of the hip-joint. It occasionally communicates with the bursa between the tendon and the ischium. == Function ==