title: [Reverse Chaddock sign].
abstract: It is widely accepted that the Babinski reflex is the most well-known and important pathological reflex in clinical neurology. Among many other pathological reflexes that elicit an upgoing great toe, such as Chaddock, Oppenheim, Gordon, Schaefer, and Stransky, only the Chaddock reflex is said to be as sensitive as the Babinski reflex. The optimal receptive fields of the Babinski and Chaddock reflexes are the lateral plantar surface and the external inframalleolar area of the dorsum, respectively. It has been said that the Babinski reflex, obtained by stroking the sole, is by far the best and most reliable method of eliciting an upgoing great toe. However, the Chaddock reflex, the external malleolar sign, is also considered sensitive and reliable according to the literature and everyday neurological practice. The major problems in eliciting the Babinski reflex by stroking the lateral part of the sole are false positive or negative responses due to foot withdrawal, tonic foot response, or some equivocal movements. On the other hand, according to my clinical experience, the external inframalleolar area, which is the receptive field of the Chaddock reflex, is definitely suitable for eliciting the upgoing great toe. In fact, the newly proposed method to stimulate the dorsum of the foot from the medial to the lateral side, which I term the "reversed Chaddock method," is equally sensitive to demonstrate pyramidal tract involvement. With the "reversed Chaddock method", the receptive field of the Chaddock reflex may be postulated to be in the territory of the sural nerve, which could be supported by the better response obtained on stimulation of the postero-lateral calf than the anterior shin. With regard to the receptive fields of the Babinski and Chaddock reflexes, the first sacral dermatome (S1) is also considered a reflexogenous zone, but since the dermatome shows marked overlapping, the zones vary among individuals. As upgoing toe responses are consistently observed in the case of pyramidal tract dysfunction by both the Chaddock reflex and the reversed Chaddock method, the external inframalleolar area of the dorsum as a reflexogenous zone is considered very important. In conclusion, this method, termed the "reversed Chaddock method," is not only effective but can also help avoid false positive results due to foot withdrawal or tonic foot responses elicited on stroking the sole. I would like to propose the "reverse Chaddock sign (Tashiro sign)" as one of the 15 pathological reflexes involving the foot.
authors.affiliation: Hokkaido University, Japan.
authors.forename: Kunio
authors.initials: K
authors.lastname: Tashiro
mesh_terms: D005528:Foot / Q000294:innervation*; D049672:History, 19th Century; D049673:History, 20th Century; D006801:Humans; D007564:Japan; D009462:Neurology / Q000266:history; D012021:Reflex, Abnormal / Q000502:physiology*; D001405:Reflex, Babinski / Q000266:history; D014481:United States