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

114 INJURIES OF NERVES.
when we come to apply them to explain actual injuries,
and with their aid to recall the need for certain mechanical
conditions in order to the integrity of neural
function.
— Various forms of jyressure. It may, perhaps, seem needless
to enumerate at leno;th the various means bv which
pressure is exercised upon nerves; but it does often happen
that this cause of paralysis escapes notice, so that
again and again, both in military and civil practice, I
have met with cases in which phj'sicians had failed to
comprehend the true agency at work in producing the
symptoms.
The causes productive of pressure upon nerves may be
conveniently divided into those which act from within the
body, and physical agents which affect it from the exterior.
As a rule, the former act slowly, the latter more
rapidly, so that the results vary somewhat, as I have had
occasion to point out when discussing the physiological
pathology of nerve lesions.
Injiammatorij jjressure.— It is
extremely probable, as I
have already stated, that inflammation occasions compression
of nerve branches, and that the pain which accompanies
this condition is largely due to this physical
influence. It is also certain that the nerves of inflamed
tissues are more sensitive than others to disturbino; aojencies,
so that any
artificial or other increase ( f the normal
pressure
still further disturbs them. Compression by inflammation
is most troublesome at the points where nerves
best illustrated
pass through bony foramina, and this is
where, as in the sciatic, the inflamed nerve is so placed as
to be hurt whenever the motions \if the limb alter its
relation to the opening through which it escapes.
I am at present treating a man from Tennessee, who
received in a scuffle a kick which injured the sciatic nerve
at its point of emergence.
The blow caused intense pain,