Lumbar radiculopathy may be caused by, or confused with, many different conditions. The nature of the patient's pain-its quality, intensity, location, and profile over time-is an important guide in the evaluation. A careful but directed physical examination is necessary for the clinical evaluation of patients with lumbar spine disease. Evaluation involves inspection of the back and limbs, palpation, and observation of the patient. A careful neurological evaluation, examination of strength, deep tendon reflexes, sensation, and muscular function is necessary. Electromyography is often useful. The most commonly involved nerve roots are L3, L4, L5, and S1. Lesions of each produce distinct symptoms, and other conditions can mimic the radiculopathies. Specific investigation is necessary for an accurate diagnosis. © 1993 W.B. Saunders Company. All rights reserved.