Lateral Femoral Cutaneous Nerve

Epidural anesthesia can mask a neurological deficit, such as nerve compression of the femoral nerve and lateral femoral cutaneous nerve of the thigh from the lithotomy position (SEDA-22, 137). 

FIG. 66-2 PINS sacrum and pelvis point patterns. Anterior 6, rectus abdomlnus muscle/pubic 7, Inguinal ligament 8, lateral femoral cutaneous nerve 9, adductor (gracilis) muscle 70, sartorius. 

The lateral femoral cutaneous nerve courses more lateral relative to the femoral nerve. It arises from the L2 and L3 spinal nerve roots, emerges from the lateral border of the psoas muscle and crosses the iliacus muscle passing through a tunnel formed by a small split in the lateral end of the inguinal ligament in close proximity with the anterior superior iliac spine (Fig. 12.10b). This nerve is purely sensory and supplies the skin of the anterior and lateral aspects of the thigh. 

Fig. 12.16. Lateral femoral cutaneous nerve. Transverse 12-5 MHz US image obtained over the anterior superior iliac spine (ASIS) in a healthy subject depicts the nerve (arrow) as it passes through the tunnel formed by a split in the lateral end of the inguinal ligament (arrowheads)...

Anatomical scheme of the lateral femoral cutaneous nerve. 

Figure 108. Distribution of lateral femoral cutaneous nerve. (From Omer, G. E. and Spinner, M. Management of Peripheral Nerve Problems. Philadelphia, W. B. Saunders Co., 1980.)...

Fig. 12.42. Lateral femoral cutaneous neuropathy in a patient with chronic sensory symptoms irradiated over the anterolateral region of the thigh. Long-axis 12-5 MHz US image of the lateral femoral nerve (arrows) demonstrates a fusiform hypoechoic swelling (asterisks) of the nerve at the point where it crosses the anterior superior iliac spine (ASIS) below the inguinal ligament...

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