Pelvis & Buttock

Question 1

Gluteus Maximus

Answer 1

Origin: ilium, posterior gluteal line, dorsal surface of sacrum and coccyx, and sacrotuberous ligament

Insertion: iliotibial tract and gluteal tuberosity

Innervation: inferior gluteal nerve

Action: extension and external rotation

Question 2

Gluteus Medius

Answer 2

Origin: between anterior and posterior gluteal lines

Insertion: lateral surface of greater trochanter of the femur

Innervation: superior gluteal nerve

Action: abducts femur, keeps pelvis level when ipsilateral limb is weight bearing. Anterior fibers: internal rotation of hip

Question 3

Gluteus Minimus

Answer 3

Origin: between inferior and anterior gluteal lines

Insertion: antero-lateral aspect of the greater trochanter of the femur

Innervation: superior gluteal nerve

Action: abducts femur at hip joint and internal rotation. Also keeps pelvis level when ipsilateral limb is weight bearing

Question 4

Tensor Fascia Lata

Answer 4

Origin: ASIS

Insertion: iliotibial tract of fascia lata

Innervation: superior gluteal nerve

Action: same as glue min and med. Also stabilizes knee extension

Question 5

Piriformis

Answer 5

Origin: anterior surface of sacrum between S1-S4

Insertion: superior border of greater trochanter of femur

Innervation: spinal nerves L5-S2

Action: externally rotate extended thigh and abducts flexed thigh; steady femoral head in acetabulum

Question 6

Obturator Internus

Answer 6

Origin: inner surface of the obturator foramen

Insertion: medial surface of greater trochanter

Innervation: spinal nerve from L5-S2

Action: externally rotate extended hip and abduct flexed thigh; steady fem. head in acetabulum

Question 7

Obturator Externus

Answer 7

Origin: external surface of obturator foramen

Insertion: trochanteric fossa of femur

Innervation: obturator nerve

Action: external rotation of the extended hip; abduction of flexed hip

Question 8

Superior and Inferior Gemellus

Answer 8

Origin: Superior: ischial spine, Inferior: ischial tuberosity

Insertion: medial surface of greater trochanter

Innervation: spinal nerves L5-S1

Action: externally rotate extended thigh and abduct flexed thigh

Question 9

Quadratus femoris

Answer 9

Origin: lateral border of ischial tuberosity

Insertion: intertrochanteric crest of the femur

Innervation: spinal nerves L5-S1 (nerve to quad fem.)

Action: externally rotate hip