posterior hip: Deep: rotators of the hip joint

Question 1

piriformis

Answer 1

• origin: anterior surface of sacrum
• insertion: greater trochanter of femur
• action: abducts flexed thigh, laterally rotates extended thigh, helps stabilise hip joint

Question 2

superior gemellus

Answer 2

• origin: ischial spine
• insertion: obturator internus tendon on greater trochanter
• action: laterally rotates the femur

Question 3

obturator internus

Answer 3

• origin: the internal surface of the obturator membrane and margin of the obturator foramen
• insertion: greater trochanter
• action: laterally rotates extended thigh and abducts the flexed thigh

Question 4

inferior gemellus

Answer 4

• origin: ischial tuberosity
• insertion: obturator internus tendon
• laterally rotates extended thigh and abducts flexed thigh at hip

Question 5

obturator externus

Answer 5

• origin: the external surface of the obturator membrane and the superior and inferior pubic rami
• insertion: trochanteric fossa of femur
• action: laterally rotates the thigh
• the tendon of the obturator externus m. passes inferior to the neck

Question 6

quadratus femoris

Answer 6

• origin: ischial tuberosity
• insertion: quadrate line of the femur
• action: laterally rotates the thigh