Which of the following is NOT a hamstring muscle?

• A. Biceps Femoris
• B. Semitendinosus
• C. Semimembranosus
• D. Gastrocnemius

Answer: (D)

The main idea here is knowing which muscles belong to the hamstring group. The hamstrings are a set of three muscles on the back of the thigh: biceps femoris (long head and short head), semitendinosus, and semimembranosus. They cross the hip and knee and are the primary movers for hip extension and knee flexion.

The gastrocnemius, by contrast, is a calf muscle in the posterior leg. It crosses the knee as well as the ankle but its main job is plantarflexion of the ankle (and it can assist knee flexion under certain conditions). Because it’s located in the calf rather than the thigh and not part of the hamstring group, it is not considered a hamstring muscle.