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Obturatorius internus



  • Deep


  • Obturator foramen
    • Internal surface
  • Ischium posterior
    • Internal surface
  • Obturator membrane
  • Obturator fascia


  • Trochanter major
    • Medial surface, proximal to trochanter fossa

Main function

  • Hip
    • Lateral rotation

Secondary function

  • Hip
    • Abduction
  • Pelvis
    • Contralateral rotation

Nerve innervation

  • Segmental
    • L5-S2
  • Peripheral
    • Plexus sacralis

Arterial supply

  • Superior gluteal artery
  • Inferior gluteal artery
  • Obturator artery


  • Patient position
    • Prone
  • The obturator internus is deep and is difficult to palpate
    • You can palpate the deep lateral rotator group of the hip, of which the obturator internus is a part of, but it is difficult to isolate the palpation of the muscle
  • Place your hand just lateral to the sacrum, halway between SIPS and apex of the sacrum
  • Ask the patient to flex the knee to 90°
  • Give resistance to the patient in the direction of medial rotation, so that the patient is giving force towards lateral rotation while you feel for the contraction of the lateral rotators
  • Note that the deep lateral rotators of the hip consists of the quadratus femoris, obturator externus, piriformis, gemellus superior and gemellus inferior. It can be difficult to distinguish between these muscles, but be aware that they are all active during the movement
  • Also note that the gluteus maximus can also be activated during the movement, if you are giving too much force, so that the patient's resistance increases, this too will become active

Strength test

  • Patient position
    • Sitting with 90° flexion of the knee, while the leg is hanging freely above the ground
  • Place your one hand laterally on the patient's thigh on the side which is to be tested
  • Use the opposite hand to give resistance to the patient, place the hand along the medial side of the calf and pull the leg into an internally rotated position of the hip, so that the patient is giving force towards external rotation
  • Note that this test also tests the quadratus femoris, obturator internus, obturator externus, gemellus superior, gemellus inferior that are all a part of the deep lateral rotators of the hip