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Semimembranosus -posteromedial view
Semimembranosus -posterior view
Semimembranosus - posteromedial insertion

General information

  • This section is strictly limited to anatomy, you might be looking for clinical relevant information which is found under the clinical chapters -- muscles section, click here to go to that page


  • Partly superficial
    • Distal part of the muscle is superficial
    • Rest of the muscle is deep to semitendinosus


  • Tuberositas ischiadicum
    • Proximal and lateral to biceps femoris and semitendinosus


  • Medial condyle tibia
    • Posteromedial part

Main function

  • Knee
    • Flexion
  • Hip
    • Extension
  • Pelvis
    • Posterior tilt

Secondary function

  • Knee
    • Medial rotation
  • Hip
    • Medial rotation

Nerve innervation

  • Segmental
    • L4-S2
  • Peripheral
    • Sciatic nerve
    • Tibial nerve

Arterial supply

  • Inferior gluteal artery
  • Deep part of femoral artery
  • Obturator artery
  • Popliteal artery


  • Patient position
    • Prone
  • Place a pillow or place a chair on the treatment bench so that the patient can rest with the knee iin flexion
  • Place your hand distally and posteromedially on the patient's thigh
  • Place the other hand on the patient's heel and have the patient perform resistance in the direction of flexion
  • Feel for the contraction of the muscle
  • The muscle is both at the medial and lateral side of the semitendinosus tendon (which is superficial to the semimembranosus)

Strength test

  • Patient position
    • Prone
  • Fixate the patient's thigh down towards the bench with your one hand
  • Bend the patient's knee to 60°
  • Position the hip so that it is in slight medial rotation
  • Position the knee so that too is in slight medial rotation
  • Give resistance posteriorly and distally on the patient's calf, just proximal to the ankle
    • The pressure should be in an extension direction of the knee so that the patient is giving force towards flexion

Weakness of

  • In weakness, the patient may have problems holding the foot in the rotated position which is the starting point for the test
  • In weakness of the medial hamstrings, the medial stability will be diminished, which can result in valgus position of the knee, also called 'knock-knee'
  • If all of the hamstrings group is weak, this will lead to the knees being hyperextended
  • In bilateral weakness of both hamstrings, the pelvis will compensate by tilting anteriorly so that the patient often has a lordosis of the lower back