Injuries of nerves and their consequences - Reflex Sympathetic ...

190 INJURIES OF NERVES.
have no electric contractility, the currents applied to
them always causing contraction of the flexor group.
This case well enough illustrates how sensation may
escape, and motion be largely destroyed. The triceps
and long supinator were nearly unharmed, while the
remainder of the extensor group was totally palsied.
Such was the nature of the wound that it was easy to
see how the triceps and other brachial
muscles escaped
injury to their nerves. On the other hand, it was very
difiicult to perceive how the muscular branches to the
forearm
injury
could be so completely palsied with such trivial
to the cutaneous and radial branches of tactile
endowments.
When sensation is injured, together with motion, the
former is apt to return first. Thus, for example, a man
is shot through the arm, so as to partiallj* injure the bundle
of brachial nerves. The first result is entire loss of
both motion and sensation; but within a day or two the
latter returns to a great extent, then by degrees certain
muscles recover their power, and except for inflammatory
accidents we are in a position, at the close of a week, to
say how much of the original
loss of function is to be
permanent. Let us again examine this case at the, close
of a year, and we shall find that, counting from this time,
the gain in sensation is out of proportion greater than
that of motion.
In alluding to this fact in our little volume on nerve
wounds, and while acknowledging the difiiculty of fully
explaining the matter, we sought to account for it in the
following manner:
"When a function is partially paralyzed,
its continued
exercise is one of the conditions of its ultimate return to
full activit}' so soon as the neural injury has become repaired.
Now, the sense of touch is in constant automatic
use, so to speak, every contact being a continuous stimu-