Femoral nerve: L2–L4, course to the thigh and the muscles it supplies

Where does the femoral nerve run?

Climbing stairs or rising from a chair, the quadriceps at the front of the thigh straighten the knee. Where does the signal to those muscles come from? From the femoral nerve, coming down from the lower back.

It is the largest branch of the lumbar plexus, the network of nerves beside the lumbar vertebrae, with roots from L2, L3 and L4. In the view above it runs obliquely down and out from beside the lumbar spine along the inner wall of the pelvis toward the groin.

From the lower back to the groin

Its roots unite within the psoas major. It emerges from the lateral border of the psoas, runs down in the groove between the psoas and iliacus (supplying the iliacus), and passes under the inguinal ligament into the thigh. There it lies just lateral to the femoral artery: nerve, artery, vein from lateral to medial (NAV). The artery and vein are enclosed in the femoral sheath; the nerve lies outside it.

Branching in the front of the thigh

Within a few centimetres of the inguinal ligament it spreads into many branches like a broom.

Functionally it extends the knee through the quadriceps and flexes the hip through the iliacus and sartorius. The pectineus may also receive a branch from the obturator nerve; which nerve dominates varies between people.

Name and terms

Femoral means of the thigh. Related terms: lumbar plexus, saphenous nerve, anterior cutaneous branches. The similarly named genitofemoral nerve is a separate nerve of the same plexus. The Latin is nervus femoralis.

See it in the app

Hidden between muscles in the pelvis and branching as soon as it enters the thigh, the femoral nerve is hard to follow in one drawing. In the 3D anatomy app teamLabBody you can keep only the bones and the nerve and follow it from beside the lumbar spine to the groin, then select its anterior cutaneous branches and the saphenous nerve. Cross sections are available with the PREMIUM plan.

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