Lower Extremity Peripheral Nerve Blocks: Lateral Femoral Cutaneous Nerve Block

Lateral Femoral Cutaneous Nerve Block

The lateral femoral cutaneous nerve provides sensory innervation to the lateral thigh (see Figure 46–39). It may be anesthetized as a supplement to a femoral nerve block or as an isolated block for limited anes-thesia of the lateral thigh. As there are few vital struc-tures in proximity to the lateral femoral cutaneous nerve, complications with this block are exceedingly rare. The lateral femoral cutaneous nerve (L2–3) departs from the lumbar plexus, traverses laterally from the psoas muscle, and courses anterolater-ally along the iliacus muscle (see Figure 46–38). It emerges inferior and medial to the anterior superior iliac spine to supply the cutaneous sensory innerva-tion of the lateral thigh.

The patient is positioned supine or lateral, and the point 2 cm medial and 2 cm distal to the anterior superior iliac spine is identified. A short 22-gauge block needle is inserted and directed laterally, observing for a “pop” as it passes through the fascia lata. A field block is performed with 10–15 mL of local anesthetic, which is deposited above and below the fascia ( Figure 46–44).