Gluteal Muscles

Question 1

Gluteus Maximus (upper and lower fibers)

Answer 1

Upper
Origin: Posterior iliac crest, sacrum, thoracolumbar fascia
Insertion: Iliotibial tract
Action: extend thigh, external rotation thigh, abduction of thigh
Innervation: inferior gluteal nerve L5, S1, S2
Lower
Origin: sacrum, thoracolumbar fascia, sacrotuberous ligament
Insertion: Gluteal tuberosity
Action: extend thigh, external rotation thigh, adduct thigh
Innervation: Inferior gluteal nerve L5, S1, S2

Question 2

Gluteus medius

Answer 2

Origin: Superior gluteal surface of ilium
Insertion: Greater trochanter
Action: abduction thigh, Ant: flex and internal rotation of thigh, Post: extension thigh
Innervation: Superior gluteal nerve L4, L5, S1

Question 3

Gluteus minimus

Answer 3

Origin: inferior gluteal surface of ilium
Insertion: Greater trochanter
Action: abduction thigh, Ant: flexion and internal rotation thigh, Post: extension and external rotation thigh
Innervation: Superior gluteal nerve L4, L5, S1

Question 4

Tensor fascia latae

Answer 4

Origin: anterior superior iliac spine (ASIS)
Insertion: Illiotibial tract
Action: tenses fascia latae, abduction thigh, internal rotation thigh, flexion thigh
Innervation: Superior gluteal nerve L4, L5, S1

Question 5

Piriformis

Answer 5

Origin: anterior surface of sacrum
Insertion: greater trochanter
Action: External rotation thigh, abduction thigh, extension thigh
Innervation: direct branches from sacral plexus S1, S2

Question 6

Obturator internus

Answer 6

Origin: inner surface of obturator membrane
Insertion: greater trochanter
Action: external rotation of thigh, abduction of thigh, extension of thigh
Innervation: nerve to obturator internus L5, S1

Question 7

Gemellus superior

Answer 7

Origin: ischial spine
Insertion: medial greater trochanter
Action: external rotation thigh, adduction thigh < 30* abduction, abduction thigh > 30* abduction, extension thigh
Innervation: Nerve to obturator internus L5, S1

Question 8

Gemellus inferior

Answer 8

Origin: ischial tuberosity
Insertion: medial greater trochanter
Action: external rotation thigh, adduction thigh < 30* abduction, abduction thigh > 30* abduction, extension thigh
Innervation: Nerve to quadratus femoris L5, S1

Question 9

Quadratus femoris

Answer 9

Origin: ischial tuberosity
Insertion: intertrochanteric crest; quadrate tubercle
Action: external rotation thigh, adduction thigh
Innervation: Nerve to quadratus femoris L5, S1

Question 10

Obturator externus

Answer 10

Origin: outer surface of obturator membrane
Insertion: trochanteric fossa
Action: External rotation of thigh, adduction of thigh
Innervation: Obturator nerve L3, L4