Hamstring

Written by Dr Sheila Strover on March 14, 2025

A hamstring is one of three muscles at the back of the thigh - semitendinosus, semimembranosus or biceps femoris - which work to bend the knee.

Illustration from the back of the knee to show the attachment of the semitendinosus muscle to both the pelvis and the back of the tibia bone.
Semitendinosus - view from the back of the knee
semimembranosus.png
Semimembranosus - view from the back of the knee
Illustration of the back of the knee, showing the two heads of the biceps femoris tendon.
Biceps femoris - view from the back of the knee

The hamstring used in graft construction

The tendon of semitendinosus is commonly harvested and used in hamstrings grafts for cruciate ligament reconstruction.