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

26 INJURIES OF NERVES.
nerve contains an equal share of the nerve tnhes, hoth
of sense and motion, is not at present very clear. Such,
however, is the popular medical belief, though there is
a good deal of reason to think that the nerve filaments
of either function remain in bundles; because, as we
shall see later, it is
very common to find that a nerve
trunk, injured by a missile, has sufl:ered in its sensory
or motor functions alone, which could scarcely be accounted
for upon any other supposition than that last
mentioned. Any other explanation must presuppose some
greater susceptibility to injury in one set of fibres than in
another.
In passing from the centre to the periphery, the nerves
give ofi* branches which, as a rule,
leave the main stem at
an acute angle, and more rarely at a right angle. JSTerves
in certain positions are liable during movement of limbs
to be acutely bent, as happens at the elbow; and although
such flexion is harmless when not prolonged,
it is liable
to cause loss of function when continued for some time,
as may be felt by retaining the arm in a position
of extreme
flexion for ten or fifteen minutes.*
In their branchings nerves come into relation with
other nerves, and give or get fibres; but the function of
these is not altered thereby, nor do the nerve tubes in
man anastomose in the sense in which vessels do.
A considerable number of nerve fibres appear to form
loops, for the most part having their convexity towards
* It would appear, however, from the following instance, that recovery
from this may occur when a limb remains bent for long periods. I saw
lately, at the Hospital for Deformities and Nervous Diseases, a girl whose
left arm had been bent at a most acute angle for years, owing to the
cicatricial contraction following a burn. Although at first there was
some loss of tactile power, at present there is absolutelj- perfect sensation
thi-oughout the limb, and the intrinsic finger movements are well
preserved.