THE PLANTAR REFLEX - RePub

The plantar reflex before Babinski
DISCOVERY
Retraction of the leg caused by plantar stimulation has of course been
observed since time immemorial. The modern theory of reflex action was
founded by Descartes (1664); he postulated that certain actions resulted
from 'reflection of spirits' within the brain, in which the will took no part.
That the spinal cord, widely regarded as a bundle of cranial nerves, could
also mediate automatic acts was implied by occasional experiments of 18th
century scientists such as Hales and Whytt (see Clarke and O'Malley,
1968). The Czech physician Prochaska (1784) theorized that the reflection
of external impressions from sensory nerves into motor nerves was
mediated by a local 'sensorium commune'. Hall (1833) confirmed the
existence of the 'spinal soul' by systematic experiments, and caused great
excitement and controversy.
In the course of the 19th century, however, scientists and physicians
became accustomed to these ideas. Withdrawal of the leg in man was
particularly analogous with Hall's animal experiments, and continued to be
regarded as a medullary automatism even when at one time the pathways
of later discovered reflexes were in dispute. It was found in normal subjects
as well as in disease. One way of evoking this reflex was by forceful passive
flexion of the toes. Brown-Sequard (1868) relates how he first observed
this manoeuvre in Paris, nine years before, performed by the valet of a
young American suffering from paraplegia- it stopped extensor spasms
and made dressing possible. Brown-Sequard introduced the procedure into
both the French and the English school of neurology. Later it was
rediscovered by Sinkler (1888) - his claims were voiced by Wartenberg
(1947, 1951)- and again by Bechterew (1906).
It was more usual, however, to stimulate the sole of the foot in order to
bring about reflex withdrawal of rhe leg, and depending on the stimulus
intensity this resulted either in dorsiflexion of the foot alone, or in flexion
of knee and hip as well. It is in this sense that we encounter the 'plantar
reflex' as part of the neurological examination: in articles by Schwarz
(1882) and Geigel (1892), and in the well-known textbooks by Wernicke
(1881), Gowers (1892) and Blocq & Onanoff (1892). Most authors
concurred that the plantar reflex was 'diminished' in hemiplegia.
Movements of the toes during reflex flexion of the leg were initially
overlooked or mentioned only in passing. Oppenheim (1889) noted
plantar flexion of the toes in a few normal subjects. On the other hand,
Wernicke ( 1881) mentioned dorsiflexion of the toes as being the normal
response, and this mistaken belief was widely shared, at least in Germany.
This is testified by the many surprised reactions to Babinski's discovery,
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