Obturator Internus
Musculus obturator internus
The obturator internus arises inside the pelvis, turns sharply around the lesser sciatic notch like a pulley, and joins the two gemelli to form the triceps coxae that externally rotates and stabilizes the hip. It abducts the flexed hip and is an important deep stabilizer of the femoral head. It is conditioned through rotational and single-leg control rather than direct loading.
- Actions
- Hip external rotation (extended hip), Hip abduction (flexed hip), Hip joint stabilization
- Origin
- Internal surface of the obturator membrane and surrounding bony margins of the obturator foramen
- Insertion
- Medial surface of the greater trochanter of the femur (trochanteric fossa)
- Innervation
- Nerve to obturator internus (L5-S2)
- Blood supply
- Internal pudendal and inferior gluteal arteries
Antagonists Tensor Fasciae Latae