The femoral nerve is formed by the ventral rami of L2-L4, specifically the posterior divisions of the lumbar plexus.
The femoral nerve travels posterior to the inguinal ligament within the muscular lacuna. The muscular lacuna also contains the iliopsoas muscle.
NAVEL is a mnemonic for remembering the neurovascular structures that travel deep to the inguinal ligament into the femoral triangle.
N = femoral nerve
A = femoral artery
V = femoral vein
EL = empty space (femoral canal) and lymphatics
The femoral nerve provides motor innervation to the muscles of the anterior compartment of the thigh, with a few exceptions:
-the psoas portion of iliopsoas is innervated by muscular branches of the lumbar plexus
-tensor fasciae latae is innervated by the superior gluteal nerve
-pectineus is occasionally innervated by the obturator nerve
The femoral nerve provides sensory innervation to the skin of the anterior thigh and the anteromedial aspect of the leg. The afferent innervation of the leg is provided by the saphenous nerve (a branch of the femoral nerve that travels in the adductor canal).
Injury to the femoral nerve typically produces: weakness of hip flexion, loss of knee extension (no patellar reflex), and sensory loss over the territories described above.