WHAT IS INVOLVED

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Lateral Cutaneaous Nerve of Thigh


LOCATION

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Lateral Cutaneaous Nerve of Thigh in the upper and outer thigh


COMMON SYMPTOMS

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- Pain, burning in the thigh

- Poor tolerance to touch, clothes, cover or anything that rubs against thigh

- In mothers (or fathers) pain/burning with children sitting on lap

- No thigh or leg weakness or atrophy

- Usually unilateral

- Symptoms always present, no night/day preference


ONSET

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- Usually Gradual over days, weeks

- May be Sudden


RISK FACTORS

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- No gender preference

- Diabetes or family history of Diabetes, Alcoholism or other occupational or nutritional causes of Neuropathies, HIV infection

- Overweight

- Tight undergarments or clothing in the inguinal area


EXAM

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- Decreased sensation over upper and lateral area of thigh

- Sometimes decreased sensation all the way to the patella

- Difficult to examine because of pain/burning induced by touching or rubbing

- Normal strength, no atrophy in thigh muscles

- Preserved Knee Jerk (if absent or unilaterally decreased suspect L3 root lesion)


LOCALIZATION

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Pure sensory branch involvement at the upper and lateral end of the inguinal ligament


EMG

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- Study Lateral Cutaneous Nerve of Thigh, usually small amplitude (<10 μV)

- Study both sides to compare amplitudes

- Response may be absent or significantly (<50%) smaller than healthy side

- Nerve Conductions may be difficult to perform in overweight subjects

- Rule out L3 root lesion by studying other Femoral and non-Femoral innervated muscles to include:

.... - Vastus Lateralis (derived from Femoral Nerve below Inguinal ligament)
.... - Ilio-Psoas (from Femoral Nerve above Inguinal ligament)
.... - Thigh Adductors (from Obturator Nerve)

- In Meralgia Paresthetica, the needle exam of the Thigh muscles will be normal

- In L3 root lesions, Vastus Lateralis, Ilio-Psoas, Thigh Adductors and/or paraspinals could be involved

- In Femoral Nerve lesions, Vastus Lateralis and Ilio-Psoas, but not Thigh Adductors, are involved

- In Obturator Neuropathy, only Thigh Adductors are involved


RECOMMENDATIONS

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- Can be very annoying

- Symptomatic treatment

- Stop/decrease cause, tight undergarments, clothing

- Lose weight

- Anti epileptics, tricyclics have been tried with various degrees of success

- Nerve blocks/Injections


WHAT ELSE COULD IT BE?

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- Could be an L3 root lesion if associated muscle weakness (Vastus Lateralis, Ilio-Psoas and/or Thigh adductors) or absent or unilaterally decreased Knee jerk

- Few other conditions can cause the same symptoms