Abnormal pyramidal sign Chaddock reflex 2010-09-07T12:11:07Z HP:0010875 A diagnostic reflex elicited by stimulation of the skin over the surface of the lateral malleolus of the foot. The Chaddock refelx is present if there is extension of one or more or all of the toes with or without fanning of them when the external inframalleolar skin is stimulated. The Chaddock sign, similar to the Babinski sign, is taken to be an indication of disease of the spinocortical (pyramidal) tract. SNOMEDCT_US:413813004 UMLS:C1531651