The plantar reflex : a historical, clinical and electromyographic study

The plantar reflex is one of the most important physical signs in medicine. Few patients undergoing a full medical examination can avoid having their soles stroked, because an upgoing great toe is regarded as a reliable sign of dysfunction of corticospinal nerve fibres. So far, there is little to justify a new study. One problem is, however, that it can be difficult to determine the direction of the reflex response: the movements of the great toe may be slight, wavering, inconstant, or masked by voluntary activity. Soon after the introduction of the reflex the comment had already been made that ' the average ward clerk's notes are quite worthless on the subject of the plantar reflex, though he may make fair notes on the knee jerk and the pupil reflex to light' (Harris, 1903 ). Anyone who is a regular participant in medical ward rounds knows that controversies about plantar reflexes still abound today. Decisions in such cases are ususally guided by a mixture of seniority and ill-defined intuition. This is because the toe response is widely regarded as an oracle which often speaks in riddles, rather than as a definite reflex phenomenon, subject to the rules of physiology. But to give the plantar reflex its proper value, the neurologist must be aware of what is happening in the spinal cord. Therefore the first leading theme of this study was to ascertain the connections between the roe responses and other spinal reflexes, and to apply these physiological relationships to the interpretation of equivocal plantar responses. A review of previous clinical studies about the plantar reflex precedes the actual experiments. Since Babinski discovered the toe response in 1896, he has been awarded a prominent place on the neurological Olympus, and his papers on the subject have been canonized (Wilkins and Brody, 1967). However, to get full insight into the meaning of Babinski's words, we must connect these with pre-existing concepts, with the subsequent development of Babinski's own ideas, and with additional clinical and physiological observations of others.