lateral femoral cutaneous nerve

The lateral femoral cutaneous nerve, also known as the lateral cutaneous nerve of the thigh, is a sensory branch of the lumbar plexus arising from the posterior divisions of the anterior rami of L2 and L3 spinal nerves. The nerve supplies the skin on the anterior and lateral aspects of the thigh to the level of the knee.

Gross anatomy

Origin

The lateral femoral cutaneous nerve is formed by the posterior divisions of L2 and L3 spinal nerves (whereas the anterior divisions of these nerve roots contribute to the obturator nerve). The nerve emerges from the lateral border of the psoas major muscle inferior to the iliolumbar ligament and then courses laterally around the iliac fossa on the anterior surface of the iliacus muscle deep to the iliac fascia.

Course

Approximately 3 cm (1 inch) above the inguinal ligament the lateral femoral cutaneous nerve slopes gently forward to lie within the fibrous tissue of the iliac fascia. The nerve passes below, or occasionally perforates, the inguinal ligament to enter the thigh within a fibrous compartment just medial to the anterior superior iliac spine, passing over the sartorius deep to the fascia lata where it divides into anterior and posterior branches.

Branches and supply

The lateral femoral cutaneous nerve divides into anterior and posterior branches to supply the anterior and posterior aspects of the lateral thigh as far inferiorly as the knee.

• the anterior branch typically contains all L3 fibers of the nerve and terminal branches are distributed along the anterolateral surface of the thigh with terminal twigs also donated to the patellar plexus
• the posterior branch typically contains all L2 fibers and continues down the posterolateral aspect of the thigh along the iliotibial tract contributing terminal filaments that pass across the lateral and posterior surfaces of the thigh

Relations

The lateral femoral cutaneous nerve, like the femoral nerve, is formed from the posterior divisions of the anterior rami of L2 and L3 spinal nerves. It courses on the anterior surfaces of the iliacus muscle after becoming secured in the fibrous sheath overlying the iliacus muscle, the iliac fascia. The nerve passes under the lateral aspect of the inguinal ligament, in a compartment sometimes called the muscular lacuna, approximately 10-15 mm medial to the ASIS to lie on the anterior surface of the sartorius muscle and deep to the fascia lata. Both the anterior and posterior divisions of the nerve eventually pierce the fascia lata to give terminal cutaneous branches.

Variant anatomy

Occasionally the lateral femoral cutaneous nerve may arise from L1 and L2 nerve roots and very occasionally from L2 alone. The lateral femoral cutaneous nerve is derived from the femoral nerve in approximately 10% of cadavers studied ostensibly, because the femoral nerve is also derived from posterior divisions of the anterior rami of the lumbar nerves.

Cases of the lateral femoral cutaneous nerve bifurcating within the pelvic cavity have also been documented.

Related pathology

• meralgia paraesthetica: the lateral cutaneous nerve of the thigh is sometimes compressed as it passes under the inguinal ligament or occasionally where it pierces the fascia lata and may cause pain in the lateral aspect of the thigh; decompression of the nerve may be required

Siehe auch:

• Leistenkanal
• Meralgia paraesthetica