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Anatomy pictures

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

Referred pain pattern

Semimembranosus and semitendinosus -

Muscle Type

  • Postural


  • Pain or limping while walking
  • Pain in buttocks, upper thigh or knee when sitting
  • Sciatica or pseudo-sciatica
  • Inability of complete range of motion in extension of knee
  • 'Growing pains' in children
  • Pelvic distortions and SI-joint dysfunction
  • Tendinitis or bursitis at attachment

Muscular attachments


Short version

Detailed version

Alternative short version

Alternative detailed version

Important functions

  • Gives support to the sacroiliac joint by giving a stabilizing influence via the sacrotuberous ligament

Notes of clinical importance

  • Releasing or relaxing a tense Hamstrings might put an unstable sacroiliac joint at risk by removing the hamstrings' protective influence (the Hamstrings stabilizes the SIJ joint)
  • The 4 major muscles that creates the stability for the SIJ joint is the Erector Spinae, Biceps Femoris, Latissimus dorsi and Gluteus Maximus

Myofascial lines

Dorsal line:



  • Distal part is superficial
  • The remaining part of the muscle lies deep to the semitendinosus


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


  • Posteromedial part of the medial condyle of the tibia

Main function

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

Secondary function

  • Knee
    • Medial rotation
  • Hip
    • Medial rotation

Nerve innervation

  • Segmental
    • L4-S2
  • Peripheral
    • Nervus sciaticus
    • Nervus tibialis

Arterial supply

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