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

CHAPTER III.
NEURO-PHYSIOLOGY.
Varieties of nerves. — The nerves wliicli connect a limb
with the centres fulfill the following functions :
They
convey outwardly motor impressions, resulting in voluntary
or involuntary motion, as the case may be. They
carry centripetally the myriads of impressions which constitute
sensations, or which, unfelt as sensations, are excitomotory
in purpose.
sympathetic, exercises control over the flow of blood to the
tissues. Section of these nerves paralytically dilates the
Lastly, a system of nerves, known as
vessels; galvanization contracts them. This s^'stem originates
in the spinal cord, but there is also evidence that
certain spinal nerves, unrelated to the sympathetic, possess
the power to cause directly enlargement of arterioles and
increase of vasal supply.
Through this compound group of nerves occur such
nutritive changes as depend on increased or lessened flow
of blood, but these are insuflicient to account for all the
trophic changes which we witness from disease or injury;
and hence has arisen the belief that there are also trophic
nerves proper, which, apart from variable blood supplies,
or in connection with these, bring about in the tissues
alterations, examples of which I shall have to point out
from time to time.
In connection with nerve wounds and their consequences,
we have to deal with alterations due to the
destruction or irritation of the various fibres of nerves
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