The hamstring portion of the adductor magnus is supplied by which nerve?

The hamstring portion of the adductor magnus is supplied by which nerve?

• A. Obturator nerve
• B. Common fibular portion of the sciatic nerve
• C. Tibial portion of the sciatic nerve
• D. Femoral nerve

Answer: (C)

Two-part innervation of a single muscle shows how its different regions can be served by distinct nerves. The adductor magnus has an adductor part and a hamstring part. The adductor part is supplied by the obturator nerve, fitting its role in medially positioning the thigh. The hamstring part, which behaves like a hamstring by extending the hip and flexing the knee, is supplied by the tibial portion of the sciatic nerve. This tibial division carries fibers to the posterior thigh muscles (like the semitendinosus, semimembranosus, and the long head of the biceps femoris) and also to the hamstring portion of adductor magnus. The common fibular (peroneal) portion of the sciatic nerve innervates other muscles such as the short head of the biceps femoris, not the hamstring part of adductor magnus. The femoral nerve supplies the anterior thigh muscles, not this posterior/hamstring region.

Two-part innervation of a single muscle shows how its different regions can be served by distinct nerves. The adductor magnus has an adductor part and a hamstring part. The adductor part is supplied by the obturator nerve, fitting its role in medially positioning the thigh. The hamstring part, which behaves like a hamstring by extending the hip and flexing the knee, is supplied by the tibial portion of the sciatic nerve. This tibial division carries fibers to the posterior thigh muscles (like the semitendinosus, semimembranosus, and the long head of the biceps femoris) and also to the hamstring portion of adductor magnus. The common fibular (peroneal) portion of the sciatic nerve innervates other muscles such as the short head of the biceps femoris, not the hamstring part of adductor magnus. The femoral nerve supplies the anterior thigh muscles, not this posterior/hamstring region.