Back pain occurring without external force is extraordinarily prevalent in all segments of society. The practicing internist is often faced with the complaint, a need to define its cause, and a request to render an opinion as to whether the patient is disabled in the context of his employment. This opinion will have some weight in determining compensability under workmen's compensation law. This essay examines the inferences, as regards back pain, upon which compensation law is based. These inferences are then tested in light of our current understanding of the pathophysiology of back pain. A number of fallacies become apparent that may provide impetus for remedial legislation and clearly mandate further clinical investigation.