Erb and Westphal: simultaneous discovery of the deep tendon reflexes.

Although the deep tendon reflexes (DTRs) were first introduced simultaneously into the medical literature by Erb and Westphal (1875), there is some evidence that the knee jerk response was well known to laymen prior to that time. Erb wrote that while he was not calling attention to anything new, he realized the utility of the phenomenon in diagnosing certain disease states. Erb viewed the phenomenon more clearly as a true reflex arc, whereas Westphal interpreted it as a local muscle phenomenon. By 1885, the maneuver was used in Europe and across the Atlantic in America. By then, the DTRs had become one of the cardinal features of the neurological examination.