Author: Dr Peter de Souza
Last modified: 7 November 2022

The semimembranosus muscle is one of the 3 muscles of the posterior compartment of the thigh. The posterior compartment muscles of the thigh are collectively referred to as the "hamstrings", and function to extend the thigh at the hip joint, and flex the leg at the knee joint.

The other two muscles of the posterior compartment are the biceps femoris and the semitendinosus.


  • Ischial tuberosity


  • Posteriorly on the medial tibial condyle


  • Flexion of knee
  • Extension of hip
  • Medial rotation of tibia (esp. when knee flexed)


  •  Tibial nerve: L5, S1, S2

Blood Supply

  • Profunda femoris artery
  • Popliteal artery
  • Inferior gluteal artery