Muscles of Gluteal Region and Hip

Question 0

Gluteus Medius

Answer 0

Origin: external surface of ilium between anterior and posterior gluteal lines
Insertion: lateral surface of greater trochanter of femur
Innervation: superior gluteal nerve (L4, L5, S1)
Action: abduct and anterior portions medially rotate hip joint (posterior laterally rotate the hip joint); keep pelvis level when opposite limb is elevated

Question 1

Gluteus Maximus

Answer 1

Origin: Ilium posterior to posterior gluteal line; dorsal surface of sacrum and coccyx; sacrotuberous ligament
Insertion: most fibers in iliotibial tract, which inserts into lateral condyle of tibia; some fibers insert on gluteal tuberosity of femur
Innervation: Inferior Gluteal Nerve (L5, S1, S2)
Action: Extends hip joint between flexed and standing positions and assists in its lateral rotation; steadies thigh and assists in rising from sitting position

Question 2

Gluteus Minimus

Answer 2

Origin: external surface of ilium between anterior and inferior gluteal lines
Insertion: anterior surface of greater trochanter of femur
Innervation: superior gluteal nerve (L4, L5, S1)
Action: abduct and anterior portions medially rotate hip joint (posterior laterally rotate the hip joint); keep pelvis level when opposite limb is elevated

Question 3

Piriformis

Answer 3

Origin: pelvic surface of 2nd-4th sacral segments; superior margin of greater sciatic notch and sacrotuberous ligament
Insertion: greater trochanter of femur
Innervation: Anterior rami of S1 and S2
Action: laterally rotates hip joint; abducts hip joint; assists in holding head of femur in acetabulum

Question 4

Gemellae Superior

Answer 4

Origin: ischial spine
Insertion: medial surface of of greater trochanter (trochanteric fossa) of femur
Innervation: nerve to obturator internus (L5, S1)
Action: Laterally rotate extended hip joint; abduct flexed hip joint; steady femoral head in acetabulum (stabilizes hip joint)

Question 5

Gemellae Inferior

Answer 5

Origin: ischial tuberosity
Insertion: medial surface of of greater trochanter (trochanteric fossa) of femur
Innervation: nerve to quadratus femoris (L5, S1)
Action: Laterally rotate extended hip joint; abduct flexed hip joint; steady femoral head in acetabulum (stabilizes hip joint)

Question 6

Obturator Internus

Answer 6

Origin: pelvic surface of ilium and ischium; obturator membrane
Insertion: greater trochanter of femur
Innervation: nerve to obturator internus (L5, S1, S2)
Action: laterally rotates hip joint, assists in holding head of femur in acetabulum

Question 7

Quadratus Femoris

Answer 7

Origin: lateral border of ischial tuberosity
Insertion: Quadrate tubercle on intertrochanteric crest of femur and area inferior to it
Innervation: Nerve to quadratus femoris (L5, S1)
Action: laterally rotates hip joint; pulls femoral head into acetabulum to stabilize hip joint/pelvis

Question 8

Tensor Fasciae Latae

Answer 8

Origin: ASIS, anterior part of iliac crest
Insertion: iliotibial tract, which attaches to the lateral condyle of tibia (Gerdy condyle)
Innervation: superior gluteal nerve (L4, L5, S1)
Action: flexes hip joint; acts with gluteus maximus to stabilize the extended knee