The muscles that show up on an anatomy chart of a hamstring are the semitendinosus, the semimembranosus and the biceps femoris, according to the American Academy of Orthopaedic Surgeons. The biceps femoris is a muscle that is found at the back of the thigh, says Healthline. It has a long head and a short head.
The long head of the biceps femoris muscle connects to the ischium, which is the lower back of the hip bone, claims Healthline. The short head is attached to the thigh bone, or the femur. It is largely responsible for the way the knee flexes, how the hip extends and how the leg rotates.
The semimembranosus muscle runs from the area of the pelvic bone known as the tuberosity of the ischium to the back of the tibia, the stronger of the two bones found in the lower leg, states Healthline. It helps the leg rotate and flex and helps the extension of the thigh.
The semitendinosus muscle is a long, strap-like muscle found on the inside of the back of the thigh, claims Innerbody. It connects the ischium to the end of the tibia. It was given its name because it becomes more like a tendon around the middle of a person's thigh. It also helps to extend the thigh and rotate the leg.