THE PLANTAR REFLEX - RePub

without an ipsilateral upgoing toe sign. Conjectures about the mechanism
of its appearance included segmental irradiation of the normal response
from the stimulated side (Parhon and Goldstein, 1902; Bramwell, 1903 ).
The latter retracted his theory in 1911, when he reported a patient with
bilateral Babinski signs as well as crossed downward responses. Others
have suggested short-circuiting of cortex-bound 'flexor' impulses to the
contralateral side (Knapp, 1907), or diversion of these impulses via the
uncrossed pyramidal tract (Sana, 1901; Fairbanks, 1911).
Speculations became superfluous when again Marie and Foix (1913,
1915), and Walshe (1914) pointed out that the contralateral downward
movements of the toes were part of an extensor synergy, although often
being the minimal response. A similar interpretation had been given
earlier by Striimpell in 1899 (he produced it from the hemiplegic side,
which is rare). Accurate description of this crossed extensor reflex as a
regular accessory to the flexion reflex also stemmed from the work of
Sherrin_gton (1910) in spinal animals.
Plantar flexion of the opposite toes is not necessarily a pathological
reflex - it has been found in normal subjects by Collier ( 1899) and
Fairbanks (1911); Klippel and Wei! (1908) and Pastine (1913 a) encountered
it frequently in tuberculous patients.
2. Crossed dorsiflexion of the hallux is not met with in the absence of
pyramidal lesions. Most reports relate to patients with bilateral corticospinal
involvement (Collier, 1899; Walton and Paul, 1900; Parhon and
Goldstein, 1902; Bramwell, 1911; Fairbanks, 1911; Kidd, 1911; Brain and
Wilkinson, 1959). Only Maas (1911) and Pas tine 1913 a) found it in some
cases of hemiplegia, on stroking the sole of the non-paretic side.
A correlation with spinal synergies in animals is less obvious here than
it is in the case of the flexion reflex, crossed extension reflex or ipsilateral
limb extension. In human cases of long-standing paraplegia, however, the
occurrence of simultaneous flexor spasms in the lower limbs is welldocumented
(Riddoch, 1917: 'mass reflex').
Tonic plantar flexion of the toes in hemiplegia
Of thirty-six patients with organic hemiplegia in whom the plantar
reflexes were examined by Collier in 1899, three cases did not only show
'flexor responses' (in Collier's words) on both sides, but also the downward
movement of the toes was even' ... more marked on the paralysed side and .
very atypical, consisting of vigorous flexion of all the toes'. A similar
paradoxical downward toe response in cerebral lesions has been the subject
of a number of heterogeneous reports.
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