Hamstring Muscles

As the name implies, the "biceps femoris" has two heads, or immovable ends, one attached to the ischium (bone in the pelvis) and the other attached to the femur (thigh bone). The muscle passes along the back of the thigh on the lateral side and connects close to the midline ends of the fibula and tibia (bones in the lower leg). The biceps femoris is one of the hamstring muscles, and its tendon (hamstring) can be felt as a ridge behind the knee. This muscle functions to flex and rotate the leg laterally and to extend the thigh. The "semitendinosus" is another of the hamstring muscles. It is a long, bandlike muscle on the back of the thigh toward the inside, connecting the ischium to the proximal end of the tibia. It is so named because it becomes tendinous in the middle of the thigh, continuing to its movable end as a long, cordlike tendon. It functions to flex and rotate the leg medially and to extend the thigh. The "semimembranosus" is the third hamstring muscle and is the most inner-located muscle in the back of the thigh. It connects the ischium to the tibia and functions to flex and rotate the leg medially and to extend the thigh.