hamstring muscles

In human anatomy, a hamstring is any one of the three posterior thigh muscles in between the hip and the knee (from medial to lateral: semimembranosus, semitendinosus and biceps femoris). Etymology The word "ham" is derived from the Old English ham or hom meaning the hollow or bend of the knee, from a Germanic base where it meant "crooked". It gained the meaning of the leg of an animal around the 15th century. String refers to tendons, and thus, the hamstrings are the string-like tendons felt on either side of the back of the knee. Criteria The common criteria of any hamstring muscles are: Muscles should originate from ischial tuberosity. Muscles should be inserted over the knee joint, in the tibia or in the fibula. Muscles will be innervated by the tibial branch of the sciatic nerve. Muscle will participate in flexion of the knee joint and extension of the hip joint. Those muscles which fulfill all of the four criteria are called true hamstrings. The adductor magnus reaches only up to the adductor tubercle of the femur, but it is included amongst the hamstrings because the tibial collateral ligament of the knee joint morphologically is the degenerated tendon of this muscle. The ligament is attached to medial epicondyle, two millimeters from the adductor tubercle.