Bauhaus-Universität Weimar

OP ANTAGONIST GROUPS OP MUSCLES. 
669 
of the spinal cord, though the cause has here a uniform action, gives rise to tetanic 
convulsions, which occur in paroxysms. These phenomena, together with the periodic 
character of the attacks of epilepsy, while the operation of their causes is constant, 
seem to show that the excitability of the nervous centres is exhausted by the constant 
impression of morbid irritation, just as the excitability of the nerves is temporarily 
lost under the influence of impressions which excite them, in consequence of the 
change produced in the nervous matter by the excitement, and that the power of re¬ 
acting depends in both cases on the excitability being restored by rest. The fading 
away of the image of a coloured spot on which the eyes are long fixed, and its reap¬ 
pearance after an interval, and the periodic daily return of the states of sleep and 
waking in the sensorium, are phenomena which are typical of all such healthy or 
morbid periodic actions; for in these instances also the reaction ceases at intervals for 
a time, although the exciting impressions are constantly the same. 
3. Antagonistic movements.—The action of muscles is not restricted 
to their occasional contraction when excited by discharges of nervous 
influence. There are grounds for believing that the muscular fibres, 
particularly those of the animal system of muscles, are constantly in a 
state of slight contraction, even during their apparent repose. The re¬ 
traction of divided muscles in a living body, and, still more, the mani¬ 
fest contraction of muscles of which the antagonists are divided or 
paralysed, are in favour of this opinion. When the muscles of one 
lateral half of the face are paralysed, those of the opposite half draw 
the features towards their side. The tongue, when one-half of it is 
paralysed, is always drawn to the opposite side; and in cases of 
removal of the middle portion of the lower jaw, whereby the muscles 
which draw the os hvoides and tongue forwards,—namely, the ante¬ 
rior belly of the digastricus, the mylo hyoideus, the genio-hyoideus, and 
the genio-glossus,—lose their fixed point of attachment, the os hyoides 
is drawn backwards by the stylo-hyoideus, and the tongue by the stylo¬ 
glossus, so forcibly, that great danger of suffocation arises. Hence it 
would appear that the state of inaction of the different parts of our 
body does not indicate an absolutely relaxed condition of the muscles, 
but rather that the different groups of muscles antagonise and balance 
each other; and that when the position of a part is changed from the 
medium state of apparent rest, one or more of the muscles, already in 
a state of antagonistic action, are merely thrown into more powerful 
contraction. 
The antagonism of muscular motions is of great pathological import¬ 
ance. Distortions are produced by the balance of the action of muscles 
being destroyed. Clubfoot, for example, which may take its rise dur¬ 
ing the first months of pregnancy as well as after birth, is frequently 
owing to the prope/ balance in the antagonistic action of the muscles 
which elevate the inner and outer borders of the foot being lost, and is 
often cured by restoring the balance of action. Either the peroneal 
muscles which elevate the outer border of the foot are partially para¬ 
lysed, or the muscles which raise the inner border are in a state of 
“ paralytic contraction.” In either case the foot rests on its outer 
margin, and is drawn inwards by the tibialis posticus muscle. After a 
time, however, the position of the bones forming the joints is altered; 
the os naviculare is generally turned inwards, and the head of the 
astragalus, left partly exposed, forms a prominence on the dorsum of the 
foot. In pes equinus, in which the heel is drawn up and the foot rests
        

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