Lateral 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)...

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...

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.)...

In a case report, a 52-year-old man with psoriasis and relapsing-remitting MS developed an injection site cutaneous necrosis that involved both subcutaneous and muscular tissue with massive oedema 21 months after GA treatment. Three days later he developed radial nerve palsy. After a few days another similar lesion appeared at another injection site [26 ]. 

Fig. 10.14a-d. Radial nerve, a Photograph of the lateral aspect of the wrist showing the relationship of the superficial cutaneous branch of the radial nerve (white dashed line) with the extensor tendons of the first (I) and third (111) compartment, b-d Transverse 15-7 MHzUS images over the first compartment of the extensor tendons obtained at the levels (horizontal black bars) indicated in a show the radial nerve (arrow) as it crosses the abductor pollicis longus (APL) and extensor pollicis brevis tendons (EPB) to reach the dorsal aspect of the hand. At the wrist, the radial nerve is very small and can be depicted as a tiny hypoechoic image only when very high-frequency transducers are used... 

Proximal to the carpal and Guyon tunnels, the median and ulnar nerves are recognized based on their peculiar fascicular echotexture. Approaching the wrist, the median nerve becomes more superficial and lateral and then runs toward midline and in a deeper position to enter the carpal tunnel (JAMADAR et al. 2001). The palmar cutaneous branch of the median nerve arises from its palmar-radial quadrant approximately 5 cm cranial to the proximal wrist crease (Taleisnik 1973). It remains bound at the main nerve trunk to leave it after approximately... 

The posterior ankle houses the sural nerve, a cutaneous sensory branch that supplies the skin of the posterolateral aspect of the inferior third of the leg, the lateral margin of the foot and the lateral side of the small toe. This nerve enters the ankle between the lateral malleolus and the Achilles tendon, accompanied by the small saphenous vein. Over the dorsum of the foot, the sural nerve anastomoses with branches of the superficial peroneal nerve. 

---