It would appear to be established that if a muscle reacts to faradism
it will recover, but the contrary proposition does not follow. It was
formerly accepted that a muscle which exhibits the reaction of
degeneration is incapable of recovery, but observation has shown that
this is not the case. Complete destruction of the motor cells in the
anterior horn of grey matter as a result of poliomyelitis is now known
to be exceptional; as a matter of fact, damage to the nerve cells is
usually capable of being repaired. The muscles governed by these cells
may appear to be completely paralysed, but with appropriate treatment
their functional activity can be restored. As functional disability is
frequently due to the affected muscle being _over-stretched_, it is of
the first importance, when the acute symptoms are on the wane, that
every care should be taken to prevent the weak muscular groups being
put upon the stretch, and the greatest attention should be paid to
_the posture of the limb during convalescence_. For example, if the
child is allowed to lie with the wrist flexed, the flexor muscles
undergo shortening, and the extensors are over-stretched and are
therefore placed at a mechanical disadvantage. As the inflammatory
changes in the anterior horn of the cord subside, the flexor tendons,
from their position of advantage, are in a condition to respond to the
first stimuli that come from their recovering motor cells, while the
extensors are not in a position to do so. If, on the other hand, the
wrist and fingers are maintained in the attitude of extreme
dorsiflexion, the extensors become shortened, and, relieved of strain,
they soon begin to respond to the stimuli sent them from the
recovering nerve cells. Similarly in the lower extremity, when, for
example, the muscles innervated through the peroneal (external
popliteal) nerve are paralysed, if the foot is allowed to remain in
the attitude of inversion with the heel drawn up--paralytic
equino-varus--an attitude which is rendered more pronounced by the
pressure of the bedclothes, the chance of the muscles recovering their
function is seriously diminished. Another potent factor in preventing
recovery, especially in the lower limbs, is _erroneous deflection of
the body weight_. If, for example, there is weakness in the tibial
group of muscles, and the child is allowed to walk, the eversion of
the foot will steadily increase, the tibial muscles will be more and
more stretched