Lower limb

Obturator externus

Musculus obturatorius externus

Origin

Outer surface of the obturator foramen and the surrounding pelvic bone (rami of the pubis and ischium)

Insertion

Trochanteric fossa of the femur

Function

External rotation and slight adduction of the hip

Innervation

Obturator nerve (L3-L4)

Movement & chain

Part of the deep external rotator group of the hip, together with piriformis, quadratus femoris and the obturator internus and gemelli muscles; contributes to stabilization of the femoral head during stance phase.

Palpation

Located deeply on the external surface of the obturator membrane; cannot be palpated through the thick adductor mass.

Clinical

Dynamic posterior hip stabilizer; involved in ischiofemoral impingement and at risk during anterior/posterior hip approaches.

Segmental innervation

L3-L4.

In clinical practice

Frequent repositioning to prevent trochanteric and heel pressure ulcers; ensure hip dislocation precautions in total hip arthroplasty patients.

Region in the model

Lower limb