What nerve innervates the biceps femoris long head?

What nerve innervates the biceps femoris long head?

• A. Tibial nerve
• B. Common fibular nerve
• C. Deep fibular nerve
• D. Superficial fibular nerve

Answer: (A)

Tibial division of the sciatic nerve supplies the biceps femoris long head. This muscle is part of the posterior thigh and, like the other hamstring muscles (semitendinosus and semimembranosus), it gets innervation from the tibial portion of the sciatic nerve. The short head, by contrast, is innervated by the common fibular (peroneal) nerve, which explains why two heads have different nerve supplies. The tibial nerve travels through the posterior compartment and provides motor innervation to the muscles that flex the knee and extend the hip, aligning with the function of the biceps femoris long head. Deep and superficial fibular nerves, branches of the common fibular nerve, supply the anterior and lateral compartments of the leg, not the long head of the biceps femoris. Therefore, the innervation by the tibial nerve best fits the anatomy and function of the long head.

Tibial division of the sciatic nerve supplies the biceps femoris long head. This muscle is part of the posterior thigh and, like the other hamstring muscles (semitendinosus and semimembranosus), it gets innervation from the tibial portion of the sciatic nerve. The short head, by contrast, is innervated by the common fibular (peroneal) nerve, which explains why two heads have different nerve supplies. The tibial nerve travels through the posterior compartment and provides motor innervation to the muscles that flex the knee and extend the hip, aligning with the function of the biceps femoris long head. Deep and superficial fibular nerves, branches of the common fibular nerve, supply the anterior and lateral compartments of the leg, not the long head of the biceps femoris. Therefore, the innervation by the tibial nerve best fits the anatomy and function of the long head.