Femoral Nerve Pathway

The femoral nerve originates from the lumbar plexus and is the largest branch of this plexus. Below is its detailed pathway from origin to termination:

1. Origin: Lumbar Plexus L2-L4
   • Formed by contributions from the ventral rami of L2, L3, and L4.
   • Emerges from the lateral border of the psoas major muscle.
2. Course in the Abdomen
   • Travels inferiorly and laterally between the psoas major and iliacus muscles.
   • Remains posterior to the iliac fascia.
3. Passage Under the Inguinal Ligament
   • Passes deep to the inguinal ligament in the iliac fossa.
   • Enters the femoral triangle lateral to the femoral artery and vein (outside the femoral sheath).
4. Branching in the Thigh
   • Anterior Division:
     • Intermediate and medial cutaneous nerves of the thigh (sensory).
     • Branches to the sartorius and pectineus (motor).
   • Posterior Division:
     • Motor branches to the quadriceps femoris (rectus femoris, vastus medialis, vastus intermedius, vastus lateralis).
     • Saphenous nerve (sensory).
5. Termination: Saphenous Nerve
   • The saphenous nerve is the longest branch, providing cutaneous innervation to the medial leg and foot.
   • It follows the femoral artery into the adductor canal, emerging at the medial knee.

Summary:

• Originates from L2-L4 in the lumbar plexus.
• Travels between the psoas major and iliacus muscles.
• Passes under the inguinal ligament into the femoral triangle.
• Divides into anterior and posterior branches that supply motor and sensory functions.
• Terminates with the saphenous nerve, providing sensation to the medial leg and foot.