The |biceps femoris| is included with the hamstring muscle group. The |biceps femoris| is a large muscle comprised of two heads (two points of attachment to the bone), the long head and the short head. The two muscles converge to a single ~tendon~ of insertion. This common ~tendon~ is located on the outer back corner of the knee and forms the outer hamstring. Both heads of the muscle flex (bend) the lower leg at the |knee joint| and rotate the |tibia| outward. The long head also assists with the extension and outward rotation of the thigh at the hip joint, making it a two-joint muscle, while the short head is a single-joint muscle.
