• The semitendinosus (also semitendinosus muscle, latin: musculus semitendinosus) is a long, thin muscle located in the posterior region of thigh superficially to the semimembranosus. The semitendinosus is so called because of the long length of its tendon of insertion, extending from the middle of the thigh.

    The semitendinosus originates from the ischial tuberosity and inserts onto the tibial tuberosity.

    The functions of the semitendinosus are extension of the femur, flexion and internal rotation of the knee.