Posterior Thigh Muscles

Question 1

3 muscles in posterior compartment of thigh

Answer 1

1. biceps femoris (long and short head)
2. semitendinosus
3. semimembranosus

Question 2

Semitendinosus:
origin -
insertion -

Answer 2

O: ischial tuberosity

I: medial surface of proximal tibia (pes anserinus)

Question 3

Semitendinosus:
innervation -
function -

Answer 3

innervation: tibial part of sciatic n.

function:

1. extend thigh
2. flex leg
3. internally rotate flexed leg
4. contribute to trunk extension

Question 4

Semimembranosus:
origin -
insertion -

Answer 4

O: ischial tubersoity

I: posteromedial aspect of proximal tibia

Question 5

Semimembranosus:
innervation -
function -

Answer 5

innervation: tibial part of sciatic n.

function:

1. extend thigh
2. flex leg
3. internally rotate flexed leg
4. contributes to trunk extension

Question 6

Biceps Femoris
origin -
insertion -

Answer 6

LONG HEAD O: ischial tuberosity
SHORT HEAD O: linea aspera

insertion: head of fibula (tendon is split by lateral collateral ligament)

Question 7

Biceps Femoris
innervation -
function -

Answer 7

LH innervation: tibial part of sciatic n.
SH inner.: common fibular part of sciatic n.

function:

1. extend thigh
2. flex leg
3. externally rotate flexed leg
4. contributes to trunk extension
   * (only long head works on hip)