Which nerve has spinal levels L2, L3, L4 and primarily innervates the anterior thigh muscles, including the quadriceps?

Which nerve has spinal levels L2, L3, L4 and primarily innervates the anterior thigh muscles, including the quadriceps?

• A. Obturator nerve
• B. Genitofemoral nerve
• C. Lateral femoral cutaneous nerve
• D. FemorAL nerve

Answer: (D)

The nerve in question is the one that carries L2–L4 contributions and principally supplies the anterior thigh, including the quadriceps. That’s the femoral nerve. It arises from the posterior divisions of L2–L4, travels under the inguinal ligament into the thigh, and then its motor branches innervate the quadriceps femoris group (the main knee extenders) as well as sartorius and part of the pectineus. It also provides a sensory branch, the saphenous nerve, to the medial leg. Other nerves with L2–L4 roots don’t match this pattern: the obturator nerve also comes from L2–L4 but targets the medial thigh adductors; the lateral femoral cutaneous nerve is mainly sensory to the lateral thigh; the genitofemoral nerve (L1–L2) doesn’t innervate the quadriceps.

The nerve in question is the one that carries L2–L4 contributions and principally supplies the anterior thigh, including the quadriceps. That’s the femoral nerve. It arises from the posterior divisions of L2–L4, travels under the inguinal ligament into the thigh, and then its motor branches innervate the quadriceps femoris group (the main knee extenders) as well as sartorius and part of the pectineus. It also provides a sensory branch, the saphenous nerve, to the medial leg.

Other nerves with L2–L4 roots don’t match this pattern: the obturator nerve also comes from L2–L4 but targets the medial thigh adductors; the lateral femoral cutaneous nerve is mainly sensory to the lateral thigh; the genitofemoral nerve (L1–L2) doesn’t innervate the quadriceps.