O & I: Posterior Thigh Muscles

Question 1

Origin: Semitendinosus

Answer 1

Ischial tuberosity

Question 2

Insertion: Semitendinosus

Answer 2

Pes Anserine Medial surface of superior part of tibia

Question 3

Innervation: Semitendinosus

Answer 3

Tibial Division of sciatic nerve part of tibia (L5, S1, S2)

Question 4

Action: Semitendinosus

Answer 4

extend thigh; flex leg and rotate it medially when knee is flexed. When thigh and leg are flexed, these muscles can extend trunk

Question 5

Origin: Semimembranosus

Answer 5

Ischial tuberosity

Question 6

Insertion: Semimembranosus

Answer 6

posterior part of medial condyle of tibia. Reflected attachement forms oblique popliteal ligament (to lateral femoral condyle)

Question 7

Innervation: Semimembranosus

Answer 7

Tibial Division of sciatic nerve part of tibia (L5, S1, S2)

Question 8

Action: Semimembranosus

Answer 8

extend thigh; flex leg and rotate it medially when knee is flexed. When thigh and leg are flexed, these muscles can extend trunk

Question 9

Origin: Biceps Femoris

Answer 9

Long head: ischial tuberosity

Short head: linea aspera and lateral supracondylar line of femur

Question 10

Insertion: Biceps Femoris

Answer 10

lateral side of head of fibula. Tendon is split at this site by fibular collateral ligament of knee

Question 11

Innervation: Biceps Femoris

Answer 11

Long Head: tibial division of sciatic nerve (L5, S1, S2)

Short head: common fibular division of sciatic nerve (L5, S1, S2)

Question 12

Action: Biceps Femoris

Answer 12

flexes leg and rotates it laterally when knee is flexed; extends thigh (e.g. accelerating mass during first step of gait)