posterior/lateral muscles

Question 1

Answer 1

gluteus maximus

• *proximal attachment**: ilium posterior to posterior gluteal line; posterior surface of sacrum and coccyx; and sacrotuberous ligament
• *distal attachment**: most fibres end in illiotibial tract, which inserts into lateral condyle of tibia; some fibres insert on gluteal tuberosity of femur
• *action**: extends hip joint between flexed and standing positions and assists in its lateral rotation; steadies thigh and assists in rising from sitting position
• *innervation** : inferior gluteal nerve (L5, S1,S2)

Question 2

Answer 2

gluteus medius

proximal attachment: external surface of ilium between anterior and posterior gluteal lines

distal attachments : lateral surface of greater trochanter of femur

action : abduct and anterior portions medially rotate hip joint, keep pelvis level when opposite limb is elevated

innervation : superior gluteal nerve (L4, L5, S1)

Question 3

Answer 3

gluteus minimus

proximal attachment : external surface of ilium between anterior and inferior gluteal lines

distal attachment: anterior surface of greater trochanter of femur

action : abduct and anterior portions medially rotate hip joint, keep pelvis level when opposite limb is elevated

innervation : superior gluteal nerve (L4, L5, S1)

Question 4

Answer 4

tensor fascia latae

proximal attachment : anterior superior iliac spine; anterior part of iliac crest

distal attachment : illiotibial tract, which attaches to lateral condyle of tibia (Gerdy tubercle)

action : flexes hip joint; acts with gluteus Maximus to stabilize the extended knee joint

innervation : superior gluteal nerve (L4, L5, S1)

Question 5

illiotibial tract

Answer 5

• thick band of fascia that runs laterally on the side of the thigh from the iliac crest and attaches to the knee.
• dense fibrous connective tissues that come from tensor fascia latae and gluteus maximus

Question 6

Answer 6

Piriformis

Proximal attachment: 2nd-4th sacral ligaments, greater sciatic notch and sacrotuberous ligament

distal attachment : superior border of greater trochanter of femur

action : laterally rotate extended hip joint; abduct flexed hip joint; steady femoral head in acetabulum

innervation: branches of anterior rami of S1,S2

Question 7

Answer 7

obturator internus

proximal attachment: pelvic surface of ilium and ischium; obturator membrane

distal attachment: medial surface of greater trochanter

action: laterally rotate extended hip joint; abduct flexed hip joint; steady femoral head in acetabulum

innervation : nerve to obturator internus (L5, S1)

Question 8

Answer 8

Gamelli (superior and inferior)

proximal :

• superior*: ischial spine
• inferior*: ischial tuberosity

distal: medial surface of greater trochanter

action : laterally rotate extended hip joint; abduct flexed hip joint; steady femoral head in acetabulum

innervation :

• superior* : same as obturator internus
• inferior* : same as quadratus femoris

Question 9

Answer 9

quadratus femoris

Proximal attachment : lateral border of ischial tuberosity

distal attachment : quadrate tubercle on intertrochantic crest of femur and area inferior to it

action : laterally rotates hip joint; also pulls femoral head into acetabulum to stabilize hip joint/pelvis

innervation : nerve to quadratus femoris (L5, S1)