Lower limb
Femoral nerve
Nervus femoralis
- Origin
- Largest branch of the lumbar plexus, formed by the posterior divisions of anterior rami L2, L3, L4
- Insertion
- Descends through the psoas major, enters the thigh through the muscular lacuna deep to the inguinal ligament, and branches immediately in the femoral triangle into motor and sensory divisions
- Function
- Motor to the anterior thigh muscles (iliacus, pectineus, sartorius, quadriceps femoris); sensory to the anterior/medial thigh and, via the saphenous nerve, the medial leg and foot
- Innervation
- Major mixed nerve responsible for hip flexion, knee extension, and patellar reflex arc
- Movement & chain
- Powers knee extension against gravity (standing, stair climbing) and assists hip flexion
- Palpation
- Palpable in the femoral triangle immediately lateral to the femoral artery (NAVEL arrangement: Nerve-Artery-Vein-Empty space-Lymphatics)
- Clinical
- Femoral neuropathy causing knee buckling and inability to extend the knee; compressed by retroperitoneal/iliopsoas hematomas; absent patellar tendon reflex (L3–L4)
- Segmental innervation
- L2, L3, L4 spinal cord segments
- In clinical practice
- Target for ultrasound-guided femoral nerve block providing analgesia for femur fractures and total knee arthroplasty; quadriceps strength monitoring prior to unassisted ambulation
- Region in the model
- Lower limb