The Babinski Sign

July 16, 2014

By Michael Vogel

Among the key players in the neurological revolution of the early 19th Century, few may claim as much lasting relevance as Jean-Martin Charcot. Lending his eponym to phenomena such as Charcot’s Joint (diabetic arthropathy), Charcot’s Triad (acute cholangitis) and most notably Charcot’s Disease (ALS), the French physician is widely considered to be a progenitor of modern neuroscience and psychology. However, one of Charcot’s most influential contributions to medicine is that of his protégé and contemporary, Joseph Babinski. Coming to professional fruition in 1893, Babinski is credited with the analysis and identification of several neuroses, including a peculiar diagnostic cue bearing his name today. First identified in a 26-line short form presentation at the 1896 Société de Biologie meeting, Babinski’s Sign became one of the neurologist’s most notable discoveries, and remains an invaluable resource for the modern practicing physician today.

Babinski’s sign is a neuro-pathological cue embedded within the Plantar Reflex of the foot. Elicited by a blunt stimulus to the sole of the foot, the normal adult Plantar Reflex presents as a downward flexion of the toes toward the source of the stimulus. Babinski’s sign is observed when the Hallux (big toe) exhibits dorsal extension in response to the same plantar stimulation. While a response similar to the sign exists when the plantar reflex is elicited in infants, Presence of Babinski’s sign in adults can be indicative of a lesion or damage in the corticospinal tract, and identification of the sign remains one of the least-invasive methods for supporting an Upper Motor Neuron damage diagnosis. The sign became such an integral part of neurological doctrine that Babinski’s prototype reflex hammer, developed in 1912, became one of the essential tools of a modern neurologist. Even to this day, modern neurological examination textbooks refer to Babinski’s sign as “the most colorful exam finding in neurology”. All in all, Babinski’s sign and similar examinations of the plantar reflex (Chaddock sign, Cornell sign) are fond reminders of the utility of a comprehensive physical exam and that, with proper care and attention to detail, a physician can make confident diagnostic choices using simple, concise, and interactive methods.

Goetz CG (2009). “Chapter 15 Jean-Martin Charcot and the anatomo-clinical method of neurology”. Handb Clin Neurol. Handbook of Clinical Neurology 95: 203–12. doi:10.1016/S0072-9752(08)02115-5. ISBN 978-0-444-52009-8. PMID 19892118.

Goetz CG (2002). “History of the extensor plantar response: Babinski and Chaddock signs”. Seminars in neurology 22 (4): 391–8. doi:10.1055/s-2002-36761. PMID 12539060.

Campbell, W. W., & DeJong, R. N. (2013). DeJong’s The neurologic examination (7th ed.). Philadelphia: Lippincott.

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