• The semimembranosus (also semimembranosus muscle, latin: musculus semimembranosus) is a flat, long muscle situated in the posterior region of the thigh. The semimembranosus is so called from its membranous tendon of origin.

    The semimembranosus originates from the ischial tuberosity and inserts onto the medial condyle of tibia.

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