Lower limb

Lateral femoral cutaneous nerve (LFCN)

Nervus cutaneus femoris lateralis

Origin

Arises from the posterior divisions of the L2 and L3 anterior rami of the lumbar plexus

Insertion

Courses across the iliacus muscle, passes under or through the lateral attachment of the inguinal ligament near the ASIS, and divides into anterior and posterior cutaneous branches

Function

Pure sensory innervation to the skin of the anterolateral and lateral aspect of the thigh from the greater trochanter to the knee

Innervation

Pure sensory nerve (L2–L3)

Movement & chain

Tensioned at the rigid osteofibrous angle near the anterior superior iliac spine (ASIS)

Palpation

Tinel's sign elicited ~1-2 cm medial and inferior to the ASIS

Clinical

Meralgia paresthetica (Bernhardt-Roth syndrome: painful dysesthesias, burning sensation, and numbness over the lateral thigh from nerve entrapment under the inguinal ligament due to tight belts, obesity, or pregnancy)

Segmental innervation

L2–L3 spinal roots

In clinical practice

Managed with weight loss, loose clothing, posture correction, ultrasound-guided local anesthetic/steroid injection, and surgical decompression in refractory cases

Region in the model

Lower limb