History of the Extensor Plantar Response: Babinski and Chaddock Signs

Christopher G. Goetz, MD


Semin Neurol. 2002;22(4) 

In This Article

Babinski Sign

Joseph F.F. Babinski

In 1896, prior to the founding of the French Neurological Society, new neurological phenomena, pathological cases, and recent scientific discoveries in Paris were usually presented at the lively meetings of the Société de Biologie.[2] It was here that Charcot himself had presented his early cases of amyotrophic lateral sclerosis, Duchenne had expressed his novel views on muscular dystrophy, and Broca had presented cases of subfluent aphasia.[14] Rubbing shoulders at these meetings, neurologists, other physicians, basic scientists, physiologists, and anthropologists interested in the evolution of behavior met and argued diverse topics in an informal, though often heated, forum of debate. Describing the ambience of these meetings, the young J.J. Putnam wrote to his family:

This afternoon, he took me to a séance of the Société de Biologie, where all the swells make reports. Claude Bernard, a fine-looking old man in a velvet cap and fur-trimmed coat presided, and Charcot and Vulpian and Ranvier all had their say, of which I understood more or less. . . . For all their French blood, the members behaved a good deal like schoolboys, and for all the rings of his bell, M. Bernard couldn't keep the room quiet. [17]

On February 22, 1896, 21/2 years after Charcot's death, Joseph Babinski made a short presentation summarized in just twenty-eight lines in the minutes of the society, calling attention to the extensor toe sign (Fig. 1) and linking the phenomenon directly to organically based disorders of the central nervous system.[2] The Appendix includes a translation of the presentation, but the highlights were:

Figure 1.

Extensor toe sign, demonstrated by Babinski, from his early publication.[5]

  • The sign occurred in cases of hemi- or monoplegia of organic central nervous system origin.

  • To a painful, pricking stimulus on the sole of the foot: (1) The healthy side showed flexion of thigh, leg, foot, and toes; (2) The paralyzed side showed flexion of thigh, leg, foot, but the toes extended.

  • The sign occurred as early as a few days after the onset of weakness.

  • The sign persisted in the context of chronic weakness.

In a subsequent communication on the same subject that year, Babinski noted that stroking or tickling the sole of the foot elicited the same phenomenon.[2] In later publications, he emphasized that the sign correlated with pyramidal tract disease and could be seen with cortical, subcortical, or spinal cord lesions.[18] Seven years after the initial report, Babinski further expanded his description to delineate not only the extensor toe sign but also the fanning or abduction of the toes. A contemporary humorist drew a portrait of Babinski for the popular tabloid Chanteclair (Fig. 2), where both elements of his observation were captured with the combined imagery of the toes and a fan.[15]

Figure 2.

Front cover of the popular tabloid Chanteclair (1911), showing Babinski, the extensor toe sign, a fan to emphasize the toe fanning of the reflex, and the reflex hammer Babinski used in practice.[15]

When Babinski published a full report on the reflex in the widely circulated medical weekly Semaine Médicale,[4] he articulated his views on the significance of the extensor toe sign, especially emphasizing that it did not occur in hysteria. Weakness with extensor toe signs effectively excluded hysteria as a diagnosis.[18]

This point may seem a secondary concern today, but it was at the core of Babinski's research effort. As already emphasized, Babinski's generation that succeeded Charcot's can be largely credited with the development of the clinical neurological examination as it is practiced today. Charcot and his colleagues relied predominantly on historical information and only rarely touched the patient. After Chariot's death and the resultant medical political backlash in France, students allied to Charcot, such as Pierre Marie, Gilles de la Tourette, and Babinski himself, were at a severe disadvantage for academic advancement.[19] Babinski, consciously or unconsciously, distanced himself from his mentor by emphasizing the primacy of the neurological examination to diagnosis and developed a reputation for a painstakingly meticulous examination at the bedside. He used objectively demonstrated neurological signs to study numerous conditions and also applied the technique to Charcot's cherished topic of hysteria. Again, he distanced himself from his mentor by demonstrating that hysterics could develop weakness, but the pattern of reflexes was distinct in that the extensor toe sign categorically did not appear. Charcot had maintained a clear conviction that hysteria was emotionally based but caused neurologic syndromes largely equivalent to organic disorders by affecting the same structures through functional mechanisms. The patient's history, therefore, was of diagnostic importance, but the specific signs elicited in hysteria could be identical to those of organic etiologies. Babinski's extensor toe sign proved to be a pillar in his own argument against Charcot's claims, and this discovery necessarily pulled him against the tenets of his mentor and established him as an independent neurologist.

Babinski, the Man

Had one been fortunate enough to attend the 1896 meeting of the Société de Biologie, what would one have seen? At 38 years of age, Babinski was a large man, the second son of Polish immigrants, physically embodying his Slavic heritage against the backdrop of his Mediterranean colleagues (Fig. 3). Unmarried, he remained a bachelor his entire life, living with his older brother Henri, to whom he was greatly devoted. He had met Charcot through the circumstances of placing second in a medical competition; the reward was a post on the Charcot service in 1885.[14] He therefore arrived at the celebrated Salpêtrière Hospital at the very height of Charcot's career, shortly after Charcot had been named Professor of Diseases of the Nervous System. In this environment, Babinski participated in all of the major efforts of the Charcot program, and his early career was inextricably linked to Charcot's success. When he qualified for the competitive faculty post of agrégé or Associate Professor, however, Charcot's influence was waning. Babinski failed the examination, likely as a result of fixed balloting. Babinski and his fellow Salpêtrière colleague who also failed, Gilles de la Tourette, officially protested but the vote remained unchanged. In private correspondence related to this fateful competition, A. d'Arsonval wrote to his colleague, C.E. Brown-Séquard: "Hence, the reign of Charcot at the Medical School is over."[20]

Figure 3.

Joseph Babinski (1904). From the Bibliothèque Charcot, Salpêtrière Hospital, Paris, France.

As a result of these events, Babinski never received a faculty position in the French medical system and never worked at Charcot's cherished Salpêtrière after his mentor's death. Instead, he ran the medical service that included neurology and neurosurgery cases at the nearby Pitié Hospital. Babinski's post at the Pitié Hospital was not an illustrious one.[21] It provided him, however, with the patient material for neurological studies that would result in important contributions on cerebellar ataxia and neurosurgical cases that would be studied by him and his colleagues, Thierry de Martel and Clovis Vincent. In a quiet bourgeois lifestyle, he occupied a large apartment on the Boulevard Haussmann in the fashionable neighborhood surrounding the Paris Opera. His brother was perhaps more celebrated in French society, being the culinary expert whose Gastronomie Pratique was a well-known cooking reference source of the time. He wrote using the name Ali Bab, retaining part of his surname in his clever nom de plume. In these ways, both Babinski brothers embodied the early 20th century images of self-made men, born of displaced immigrant parents, but integrated at least partly into the fabric of traditional French society.

Context and Significance

Babinski made his observations in the context of other past and contemporary discoveries. The mass flexor reflex in paralyzed animals had been known since Prochaska's early experiments[22] and had been correctly interpreted as a spinal reflex by Marshall Hall[23] and Brigham.[24] The toe extensor reflex was not specifically described in these studies.

Medieval, Renaissance, and Baroque painters had captured the extensor toe response in normal babies, and several celebrated pictures, including those of Botticelli and Raphael, show the infant Jesus responding with this reflex to various tickling maneuvers by his mother, cherubims, or other attendants (Fig. 4).[25]

Figure 4.

Small Cowper Madonna (1505) by Raphael (Raffaello Sanzio) from the National Gallery of Art, Washington DC. The portrait shows Mary's hand stroking the undersurface of Jesus' foot with an extensor toe response.

In 1874, Wernicke[26] reported toe dorsiflexion and hemiparesis, and Strümpell[27] described the sign in amyotrophic lateral sclerosis. These investigators did not provide any interpretation of the observations beyond the vague concept of a spinal reflex. In 1893, Remak noted toe extension in a patient with transverse myelitis but again did not recognize its significance.[28] For these reasons, though not the first to observe the extensor toe sign in pyramidal tract lesions, Babinski is justifiably credited for its appropriate interpretation.[29]

Following Babinski's report, several confirmatory articles appeared in the European and American literature. These studies solidified the link between the Babinski sign and lesions of the cortical spinal tract in the cortex, subcortex, and spinal cord. The first publication on the topic in English was by J. Collier in 1899, and he introduced the term in English, extensor response.[30] Throughout his career, Babinski was more celebrated internationally than in France itself. He was awarded Honorary Member status of the American Neurological Association in 1925 and was elected to the Royal Medical Society of London and the Warsaw and Cracow Neurological Societies. He was even nominated for the Nobel Prize.[21]