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Practical use of the flexion reflex<br />
Having accepted the EMG results (inconsistencies excluded), we can<br />
now compare them with the notes of the two clinical examinations which<br />
were performed in each patient. On these occasions special attention was<br />
paid to the flexion reflex as a whole, and to the time relations of this<br />
synergy to any toe movements which occurred. The action of proximal<br />
flexor muscles was particularly noted, i.e. of tensor fasciae latae, hamstring<br />
muscles, and hip flexors. This stands in some contrast to the emphasis on<br />
the tibiali' anterior as a reference muscle in the EMG procedure. The<br />
reason for the shift of attention is the supporting hand on the foot during<br />
plantar stimulation. This position sometimes makes it difficult to see<br />
dorsiflexion of the foot, and the 'tug' felt by this hand is the compound<br />
action of all flexor muscles - which is very useful information as such!<br />
In view of all previous work on the relationship between the Babinski<br />
sign and the flexion reflex, it is perhaps not surprising that in all six<br />
patients with electromyographically pathological plantar reflexes the<br />
upgoing toes were clinically found to be synchronous with activity in<br />
proximal flexors. This number is small, but I can add some results from the<br />
next chapter: of 50 patients with a unilateral Babinski sign, 48 showed<br />
activity in other (more proximal) flexor muscles.<br />
In two cases (patients 9 and 10, table XIII), there was, on clinical<br />
examination, simultaneous activity of the extensor hallucis longus and<br />
flexors of knee and hip, but electromyography showed a pathological reflex<br />
on only one occasion in each (they account for half of the four EMG<br />
inconsistencies in the study). The referring clinicians doubted if the<br />
Babinski signs were 'real', because they did not fit easily into the clinical<br />
picture, and also because they were unusually fast - but so was the flexion<br />
reflex as a whole in these two patients. Failure of the EMG technique to<br />
confirm the Babinski signs on one occasion in these two patients must also<br />
be attributed to the high speed of movement, which did not always<br />
correspond with the chosen criteria. The reproducibility of the clinical<br />
phenomena was decisive in establishing the pathological nature of the<br />
upgoing toe movements.<br />
The clinical features were even more vital in explaining why the<br />
referring physicians had had their doubts about plantar reflexes which<br />
proved to be normal electromyographically: often there were in fact<br />
upward movements of the great toe, but out of phase with the flexion<br />
reflex and in some cases not even caused by action of the extensor hallucis<br />
longus. Sometimes the confusing movements coincided accidentally with<br />
the flexion reflex and were not reproducible; fatigue of the Babinski sign<br />
(Bauer and Biach, 1910) is a negligible factor. Almost all these observations<br />
bear on patients in the first two diagnostic categories, in whom the<br />
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