Which nerve innervates the pectineus?

Which nerve innervates the pectineus?

• A. Obturator nerve
• B. Tibial nerve
• C. Common fibular nerve
• D. Femoral nerve

Answer: (D)

The pectineus is in the anterior thigh and acts to flex the hip, with some adduction. Its motor supply in the vast majority of people comes from the femoral nerve (L2–L4), which travels through the thigh to innervate the muscles of the anterior compartment, including iliacus, sartorius, quadriceps, and typically pectineus. This alignment—anterior thigh muscle with innervation from the femoral nerve—fits its location and function. There is a rare variation where an accessory obturator nerve can also contribute to pectineus innervation, but the standard and most reliable source of its motor input is the femoral nerve. The other nerves listed do not typically supply the pectineus: tibial and common fibular (branches of the sciatic nerve) serve different compartments, and the obturator nerve primarily innervates most of the other medial thigh adductors, with the pectineus not usually their main target.

The pectineus is in the anterior thigh and acts to flex the hip, with some adduction. Its motor supply in the vast majority of people comes from the femoral nerve (L2–L4), which travels through the thigh to innervate the muscles of the anterior compartment, including iliacus, sartorius, quadriceps, and typically pectineus. This alignment—anterior thigh muscle with innervation from the femoral nerve—fits its location and function.

There is a rare variation where an accessory obturator nerve can also contribute to pectineus innervation, but the standard and most reliable source of its motor input is the femoral nerve. The other nerves listed do not typically supply the pectineus: tibial and common fibular (branches of the sciatic nerve) serve different compartments, and the obturator nerve primarily innervates most of the other medial thigh adductors, with the pectineus not usually their main target.