Muscles in posterior compartment of the thigh

Question 1

Name the muscles in the posterior compartment of their thigh, what they do and what nerve innervates them

Answer 1

Bicceps femoris

Semitendinosus

Semimembranosus

Act to extend as the hip and flex at the knee

Innervated by the sciatic nerve

Question 2

Biceps femoris: attachments, actions and innervations

Answer 2

Long head from ischial tuberosity while short head from linea aspera. Heads form a tendon that inserts into head of fibula.

Flexion at the knee, extends at the hip, laterally rotates at hip and knee

Long head innervated by tibial part of sciatic nerve, short head by common fibular

Question 3

Semitendinosus: attachments, actions and innervations

Answer 3

Originates from ischial tuberosity and attaches to medial surface of tibia

Flexes leg, extends thigh, medially rotates thigh and leg

Tibial part of sciatic nerve

Question 4

Semimembranosus: attachments, actions and innervations

Answer 4

Originates from ischial tuberosity and attaches to medial tibial condyle

flexes leg, extends thigh, medially rotates thigh and leg

Tibial part of sciatic nerve