Meralgia paresthetica or Meralgia paraesthetica is numbness or pain in the outer thigh not caused by injury to the thigh, but by injury to a nerve that extends from the thigh to the spinal column. This chronic neurological disorder involves a single nerve—the lateral cutaneous nerve of thigh, which is also called the lateral femoral cutaneous nerve (and hence the syndrome lateral femoral cutaneous neuropathy).
The lateral femoral cutaneous nerve most often becomes injured by entrapment or compression where it passes between the upper front hip bone (ilium) and the inguinal ligament near the attachment at the anterior superior iliac spine (the upper point of the hip bone). Less commonly, the nerve may be entrapped by other anatomical or abnormal structures, or damaged by diabetic or other neuropathy or trauma such as from seat belt injury in an accident.
Diagnosis is largely based on patient description and relevant details about recent surgeries, hip injuries, or repetitive activities that could irritate the nerve. Examination checks for sensory differences between the affected leg and the other leg. Accurate diagnosis may require an abdominal and pelvic examination to exclude problems in those areas. Electromyographic (EMG) nerve-conduction studies may be required.
The incidence rate of MP is 4.3 per 10,000 person years. MP is more often present in patients suffering from carpal tunnel syndrome OR 7.7 (95 % CI 1.9-31.1) and is related to pregnancy OR 12.0 (95 % CI 1.2-118.0). Using a cohort (in total 173,375 patient years) of registered persons in primary care from a computerized registration network for general practitioners (GPs) in the Rotterdam area from 1990 to 1998, persons with the diagnosis MP were included.