The Lateral Femoral Cutaneous Nerve (n. cutaneus femoralis lateralis; external cutaneous nerve) arises from the dorsal divisions of the second and third lumbar nerves.
It emerges from the lateral border of the Psoas major about its middle, and crosses the Iliacus obliquely, toward the anterior superior iliac spine. It then passes under the inguinal ligament and over the Sartorius muscle into the thigh, where it divides into two branches, and anterior and a posterior.
The anterior branch becomes superficial about 10 cm. below the inguinal ligament, and divides into branches which are distributed to the skin of the anterior and lateral parts of the thigh, as far as the knee. The terminal filaments of this nerve frequently communicate with the anterior cutaneous branches of the femoral nerve, and with the infrapatellar branch of the saphenous nerve, forming with them the patellar plexus.
The posterior branch pierces the fascia lata, and subdivides into filaments which pass backward across the lateral and posterior surfaces of the thigh, supplying the skin from the level of the greater trochanter to the middle of the thigh.