What is the anatomy of the femoral nerve in nerve entrapment syndromes of the lower extremity?

Updated: Oct 15, 2019
  • Author: Minoo Hadjari Hollis, MD; Chief Editor: Thomas M DeBerardino, MD  more...
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The femoral nerve arises from the posterior divisions of the ventral primary rami of L2, L3, and L4 within the psoas major. These nerves join to form the largest branch of the lumbar plexus. The femoral nerve emerges from the lateral border of the psoas major and courses inferiorly in the intermuscular groove between this muscle and the iliacus. It passes under the inguinal ligament lateral to the femoral artery and vein and then divides into multiple branches within the femoral triangle.

In the proximal thigh, the femoral nerve divides into sensory branches, which innervate the upper and anterior thigh, and muscular branches, which innervate the quadriceps. One of the major branches is the lateral femoral cutaneous nerve. [8] Probably the best-known cutaneous nerve arising from the femoral nerve is the saphenous nerve.

Another important branch of the femoral nerve is the medial femoral cutaneous nerve, which originates just distal to the inguinal ligament, descends on the sartorius muscle, and penetrates the deep fascia about the distal third of the thigh, at which point it splits into two terminal nerve branches.

One branch of the medial femoral cutaneous nerve innervates the skin covering the medial aspect of the distal thigh and knee joint region. The second branch supplies the skin superior to the patella and shares several communicating branches with the saphenous nerve. The posterior branch of the medial cutaneous nerve travels along the medial border of the sartorius and pierces the deep fascia about the knee, also communicating with the saphenous nerve in providing cutaneous sensation to the patellar region.

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