Human leg the anterior superior iliac spine to the pes anserinus on the medial side of the knee, from where it is further extended into the crural fascia. The sartorius acts as a flexor on both the hip and knee, but, due to its oblique course, also contributes to medial rotation of the leg as one of the pes anserinus muscles (with the knee flexed), and to lateral rotation of the hip joint. There are four posterior thigh muscles. The biceps femoris has two heads: The long head has its origin on the ischial tuberosity together with the semitendinosus and acts on
Semimembranosus muscle rotate the knee: the tibia medially rotates on the femur when the knee is flexed. It medially rotates the femur when the hip is extended. The muscle can also aid in counteracting the forward bending at the hip joint. Semimembranosus muscle The semimembranosus () is the most medial of the three hamstring muscles. It is so named because it has a flat tendon of origin. It lies posteromedially in the thigh, deep to the semitendinosus. The semimembranosus, so called from its membranous tendon of origin, is situated at the back and medial side of the thigh. Its origin is the