Lateral Femoral Cutaneous Nerve

The lateral femoral cutaneous nerve is a purely sensory nerve that arises from the lumbar plexus and supplies the skin of the lateral thigh. It is clinically significant due to its common involvement in compression syndromes, particularly meralgia paresthetica, a condition characterized by burning pain, numbness, or tingling over the outer thigh.

Structure

This nerve is formed by posterior divisions of the L2 and L3 spinal nerves. It emerges from the lateral border of the psoas major muscle, crosses the iliacus, and passes beneath or through the inguinal ligament to reach the thigh.

Key Characteristics:

• Origin: Lumbar plexus (L2–L3)
• Type: Purely sensory
• Course: Passes over iliacus → under/through inguinal ligament → enters subcutaneous tissue of lateral thigh

Location

The nerve travels:

• Laterally across the iliacus muscle
• Usually passes under the inguinal ligament medial to the anterior superior iliac spine (ASIS)
• Enters the thigh deep to the fascia lata and then pierces it to supply cutaneous territory

Function

The lateral femoral cutaneous nerve provides cutaneous (sensory) innervation to the:

• Skin over the lateral thigh, from the greater trochanter to the lateral knee
• In some cases, upper portion of the lateral gluteal region (variable)

Clinical Significance

This nerve is prone to entrapment or compression, particularly at the inguinal ligament, leading to sensory symptoms:

• Meralgia paresthetica: Compression of the nerve causes numbness, tingling, and burning pain over the lateral thigh. It can be idiopathic or associated with obesity, tight clothing, pregnancy, or trauma.
• Risk during surgery: The nerve is vulnerable in anterior pelvic and hip procedures, especially near the ASIS.
• Diagnostic testing: Nerve conduction studies or diagnostic nerve blocks may help confirm meralgia paresthetica.
• Treatment: Conservative treatment includes weight loss, loose clothing, or nerve blocks; severe cases may require surgical decompression.

Although small and purely sensory, the lateral femoral cutaneous nerve has significant clinical relevance. Its superficial course near the ASIS makes it a common source of lateral thigh discomfort when compressed or entrapped.