Posterior Thigh Region: Origin, Insertion, and Action

Question 1

Gluteus Maximus

Answer 1

O: surface of posterior ilium; gluteal line; post. Inf. Surface of sacrum and coccyx
I: gluteal tuberosity; IT Band
A: extends and externally rotates hip; abducts thigh

Question 2

Gluteus medius

Answer 2

O: outer surface of ilium, between post and ant gluteal lines
I: lat and sup surfaces of greater trochanter
A: abducts thigh; anterior fibers-medically rotates thigh; posterior fibers-laterally rotates thigh

Question 3

Gluteus minimus

Answer 3

O: outer surface of ilium
I: ant surface of greater trochanter
A: abducts thigh; anterior fibers- medically rotates thigh

Question 4

Piriformis

Answer 4

O: ant surface of lateral sacrum
I: greater trochanter
A: laterally rotates thigh; abducts thigh if hip is flexed

Question 5

Quadratus femoris

Answer 5

O: lateral border of ischial tuberosity
I: quadrate tubercle near base of greater trochanter
A: laterally rotates; adducts thigh

Question 6

Biceps femoris

Answer 6

O: longhead-ischial tiberosity; shorthead- distal lines aspera and lateral supracondylar ridge
I: head of fibula and lateral consul of tibia
A: flexes and laterally rotates knee; extends thigh

Question 7

Semimembranous

Answer 7

O:ischial tuberosity
I: post medial condyle of tibia
A: extends thigh; flexes leg At knee; medially rotates knee when knee is flexed

Question 8

Semitendinosus

Answer 8

O: ischial tuberosity
I: pes anserine
A: extends thigh; flexes leg at knee; medically rotates knee when knee is flexed