Adductor magnus has a hamstring poion and adductor poion and is, therefore, pa of both the medial and posterior compaments and is dually innervated by the obturator and sciatic nerves. The common hamstring origin is the ischial tuberosity. The tibial pa of sciatic nerve innervates all the muscles of the posterior compament of the thigh , with the exception of the sho head of biceps which is innervated by its common peroneal component. Its terminal divisions go on to innervate all the muscles of the leg. Biceps femoris has a long head which arises from the Ischial Tuberosity, and a sho head which arises from the distal pa of the inferolateral aspect of the femur.