The hamstrings are formed by which muscles?

• A. Semitendinosus, Semimembranosus, Biceps femoris
• B. Rectus femoris, Vastus lateralis, Vastus medialis
• C. Tensor fasciae latae, IT band, Gluteus maximus
• D. Gracilis, Adductor longus, Pectineus

Answer: (A)

The hamstrings are the muscles on the back of the thigh that form this group: semitendinosus, semimembranosus, and biceps femoris. The biceps femoris has two heads (long and short), but together they comprise the three-muscle set that makes up the hamstrings. These muscles are responsible for knee flexion and, especially for the long head of the biceps and the semitendinosus/semimembranosus, also assist in hip extension. The other muscles listed are not part of the hamstrings: the front of the thigh houses the quadriceps (rectus femoris, vastus lateralis, vastus medialis) which extend the knee; the tensor fasciae latae, IT band, and gluteus maximus are more involved in hip abduction/extension and lateral stabilization; and the gracilis, adductor longus, and pectineus are inner-thigh adductors.