We are the deep external rotators of the hip – who are we?
A Muscle A Day – hip
Who are we?
We laterally/externally rotate the hip joint.
We abduct the flexed femur at the hip joint.
We help hold and stabilise the head of the femur in the acetabulum.
There are 6 of us.
Who are we?
We are:
obturator internus
gemellus inferior
gemellus superior
Summary
ORIGIN:
Piriformis: anterior surface of sacrum
Obturator internus: medial side of greater trochanter.
Obturator externus: obturator membrane
Gemellus superior: ischial spine
Gemellus inferior: ischial tuberosity
Quadratus femoris: lateral border of ischial tuberosity
INSERTION:
Piriformis: greater trochanter
Obturator internus: greater trochanter
Obturator externus: Trochanteric fossa of femur
Gemellus superior: greater trochanter
Gemellus inferior: greater trochanter
Quadratus femoris: intertrochanteric crest
NERVE:
Piriformis: Sacral plexus L(5), S1, 2
Quadratus femoris: sacral plexus L4, 5, S1, (2).
Obturator internus & gemellus superior: sacral plexus L5, S1
Gemellus inferior & quadratus femoris: sacral plexus L5, S1
Action: Laterally rotates hip joint. Abducts flexed femur at the hip joint. Helps stabilise the head of the femur in the acetabulum.
Common problem when tight: feet turn outwards when standing