This article provides an overview of the neurological examination and diagnostic studies commonly used in the evaluation of low back pain, information that is essential for both clinical assessment and impairment rating in the AMA Guides to the Evaluation of Permanent Impairment. Clinical evaluation begins with a careful review of medical records. After taking a thorough history, the physician performs the physical examination, including neurological testing, on the patient. The clinical evaluation also determines data needed for impairment evaluation. Neurological examination helps distinguish among the various types of pathology suggested by the history, but to some extent the neurological examination lacks sensitivity and specificity and only about two-thirds (69%) of patients with documented L4-L5 or L5-S1 disc herniations demonstrated weakness or deep tendon reflex changes. To maximize information from the evaluation, physicians routinely test for nonorganic physical signs. Isolated positive signs have no clinical or predictive value, and only a score of three or more positive signs is considered clinically significant. Further, these tests were not designed to detect malingering. Used in isolation, the history, neurological examination, and various diagnostic studies do not have the necessary sensitivity and specificity to diagnose and identify the structural pathology responsible for lumbar radiculopathy. Integrating these components into a logical, unbiased evaluation, physicians usually can perform an accurate assessment.