ABSTRACT
The testing of reflexes involving the lower extremities is a pivotal part of the modern
neurological examination. The normal response to noxious stimulation of the foot is
plantar flexion of the toes, causing them to curl downward toward the undersurface
of the foot. In 1896, Joseph Babinski described an extensor toe response that he claimed
was a consistent finding among patients with pyramidal tract lesions of the cortex,
subcortex, brain stem, or spinal cord. He considered it a distinct sign of organic
disease and found it to be absent in cases of hysterical weakness. Charles Gilbert
Chaddock admired the work of Babinski and described a modification of the Babinski
technique, demonstrating that stimulation of the lateral surface of the foot could
induce the same type of toe extension in patients with pyramidal tract lesions. The
two reflexes are complementary, and each can occur without the other, although both
are usually present in cases of pyramidal tract impairment. Although these two reflexes
are the most commonly described pathological reflexes indicative of pyramidal tract
disruption, the names of other celebrated neurologists are also linked to the study
of extensor toe signs, each having identified a variant of the Babinski sign.
KEYWORD
Extensor toe sign - Babinski - Chaddock - history of neurology - reflexes
