LL, Buttock, & Pelvis OIA

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

Innvervation: inferior gluteal nerve (L5-S2)

Main action: ext and ER

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 (L4-S1)

Main action: Abducts femur at hip joint. Also keeps pelvis level when ipsilateral limb is WB. Anterior fibers: IR at hip

Question 3

Gluteus minimus

Answer 3

Origin: between inferior and anterior gluteal lines

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

Innervation: superior gluteal nerve (L4-S1)

Main action: abducts femur at hip joint and IR (anterior fibers). Also keeps pelvis level when ipsilateral limb is WB

Question 4

TFL

Answer 4

Origin: ASIS

Insertion: iliotibial tract of fascia lata

Innervation: superior gluteal nerve (L4-S1)

Main action: ABD femur at hip joint and IR (anterior fibers). Also keeps pelvis level when ipsilateral limb WB

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 (nerve to piriformis)

Main action: ER extended thigh and ABD 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 nerves from L5-S2 (nerve to obturator internus)

Main action: ER extended hip and ABD flexed thigh; steady femoral head in acetabulum

Question 7

Obturator externus

Answer 7

Origin: external surface of obturator foramen

Insertion: trochanteric fossa of femur

Innervation: obturator nerve (L3, L4)

Main action: ER of the extended hip; ABD of flexed hip

Question 8

Superior gemellus

Answer 8

Origin: ischial spine

Insertion: medial surface of greater trochanter

Innervation: spinal nerves L5-S1

Main action: ER extended thigh and ABD flexed thigh

Question 9

Inferior gemellus

Answer 9

Origin: ischial tuberosity

Insertion: medial surface of greater trochanter

Innervation: spinal nerves L5-S1

Main action: ER extended thigh and ABD flexed thigh

Question 10

Quadratus femoris

Answer 10

Origin: lateral border of ischial tuberosity

Insertion: intertrochanteric crest of the femur

Innervation: spinal nerves L5-S1 (nerve to quadratus femoris)

Main action: ER hip