Answer: The adductor magnus (AM) muscle is composed of a pubofemoral portion (innervated by the posterior branch of the obturator nerve) and an ischiocondylar portion, the latter of which also arises from the ischial tuberosity and shares a common innervation and action as the hamstring tendons. Because of this, the ischiocondylar portion is considered by some to be part of the hamstring muscle group.