Babinski's sign I

A pathological reflex where the great toe extends and flexes toward the top of the foot and the other toes fan out when the sole of the foot is firmly stroked. Normally, the great toe is flexed when the sole of the relaxed foot is stroked. Babinski’s reflex is normal in children up to about two years of age. The persistence in older people is a sign of damage to the corticospinal tract. Because this tract is right- and left-sided, a Babinski’s reflex can occur on one side or on both sides. An abnormal Babinski’s reflex can be temporary or permanent.

The test for Babinski’s sign, called Babinski’s test, is running a pointed instrument up the lateral border of the foot and crossing to the medial side over the metatarsal pads.

The term Babinski’s sign also refers to a reflex of the forearm and indicates a lesion of the spinal cord.

Félix Alfred Vulpian, neuropathologist at the Hôpital de Salpêtrière in Paris, half a century before Babinski had observed the extension of the great toe in certain types of brain damage. The sign had also been reported three years before by Ernst Julius Remak (1849-1911), but it was Babinski who first realized its diagnostic significance.

In 1896, at a meeting of the Société de Biologie, Babinski first reported his discovery that while the normal reflex of the sole of the foot consists of a plantar reflex of the toes; an injury to the pyramidal tract will show up in an isolated dorsal flexion of the great toe. In 1903 he completed his report with another article containing a description of the fanning of the other toes.

• Comptes rendus de la Société de Biologie, 1896, volume 48, page 207.