Muscles of the gluteal region

Question 1

Piriformis

Answer 1

Origin:

• Anterior surface of sacrum between anterior sacral foramina

Insertion:

• Medial side of superior border of greater trochanter of femur

Innervation:

• Branches from S1 and S2

Function:

• Laterally rotates the extended femur at hip joint, abducts flexed femur at hip

Question 2

Obturator internus

Answer 2

Origin:

• Anterolateral wall of true pelvis, deep surface of obturator membrane and surrounding bone.
• Originates from the pubis and ischium at the obturator foramen.

Insertion:

• Medial side of greater trochanter of femur

Innervation:

• Nerve to obturator internus (L5, S1)

Function:

• Laterally rotates the extended femur at hip joint, abducts flexed femur at hip joint

Question 3

Gemellus superior

Answer 3

Origin:

• External surface of ischial spine

Insertion:

• Along length of superior surface of the obturator internus tendon and into the medial side of greater trochanter of femur with obturator interns tendon

Innervation:

• Nerve to obturator internus (L5, S1)

Function:

• Laterally rotates the extended femur at hip joint, abducts flexed femur at hip joint

Question 4

Gemellus inferior

Answer 4

Origin:

• Upper aspect of ischial tuberosity

Insertion:

• Along length of inferior of the obturator interns tendon and into the medial side of the greater trochanter of femur with obturator internus tendon

Innervation:

• Nerve to quadratus femoris (L5, S1)

Function:

• Laterally rotates the extended femur at hip joint, abducts flexed femur at hip joint

Question 5

Quadratus femoris

Answer 5

Origin:

• Lateral aspect of the ischium just anterior to the ischial tuberosity

Insertion:

• Quadrate tubercle on the intertrochanteric crest of the proximal femur

Innervation:

• Nerve to quadratus femoris (L5, S1)

Function:

• Laterally rotates femur at hip joint

Question 6

Gluteus minimus

Answer 6

Origin:

• External surface of ilium between inferior and anterior glutial lines

Insertion:

• Linear facet on the anterolateral aspect of the greater trochanter

Innervation:

• Superior gluteal nerve (L4, L5, S1)

Function:

• Abducts femur at hip joint, holds pelvis secure over stance leg and prevents pelvic drop on the opposite swing side during walking
• Medially rotates thigh

Question 7

Gluteus maximus

Answer 7

Origin:

• Fascia covering gluteus medius,
• external surface of ilium behind posterior gluteal line,
• fascia of erector spinae,
• dorsal surface of lower sacrum,
• lateral margin of coccys,
• external surface of sacrotuberous ligament

Insertion:

• Posterior aspect of iliotibial tract of fascia lata
• Gluteal tuberosity of proximal femur

Innervation:

• Inferior gluteal nerves (L5, S1, S2)

Function:

• Powerful extensor of flexed femur at hip joint, lateral stabiliser of hip joint and knee joint, laterally rotates and abducts thigh

Question 8

Tensor fasciae latae

Answer 8

Origin:

• Lateral aspect of crest of ilium between anterior superior iliac spine and tubercle of the crest

Insertion:

• Iliotibial tract of fascia lat

Innervation:

• Superior gluteal nerve (L4, L5, S1)

Function:

• Stabilises the knee in extension