Which nerve innervates the quadriceps and the iliopsoas, enabling knee extension and hip flexion?

Which nerve innervates the quadriceps and the iliopsoas, enabling knee extension and hip flexion?

• A. Obturator nerve
• B. Sciatic nerve
• C. Radial nerve
• D. Femoral nerve

Answer: (D)

The femoral nerve is the one that does this. It comes from the L2–L4 nerve roots and travels to the anterior thigh, where it innervates the iliacus (part of the iliopsoas muscle group) and the quadriceps femoris. Because the iliopsoas group (especially the iliacus part) powers hip flexion and the quadriceps powers knee extension, this single nerve enables both actions. Other nerves don’t fit the combination here: the obturator nerve mainly supplies the medial thigh adductors, the sciatic nerve covers most of the posterior thigh and the leg, and the radial nerve supplies the arm.

The femoral nerve is the one that does this. It comes from the L2–L4 nerve roots and travels to the anterior thigh, where it innervates the iliacus (part of the iliopsoas muscle group) and the quadriceps femoris. Because the iliopsoas group (especially the iliacus part) powers hip flexion and the quadriceps powers knee extension, this single nerve enables both actions.

Other nerves don’t fit the combination here: the obturator nerve mainly supplies the medial thigh adductors, the sciatic nerve covers most of the posterior thigh and the leg, and the radial nerve supplies the arm.