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

VARIETIES OF MECHANICAL INJURIES OF NERVES. 93
side, nerve tubes are seen irregularly dilated, and presenting
the nsual alterations in calibre which are observed in
nerve bundles teased out for microscopic study. Three
or four da3's later but little effort at repair is visible, and
at the point struck the nerve tubes seem to be lost
in a granular mass. Below the contusion, they present
the appearance of granular fatty degeneration, with the
well-known coagulation of the medullar}^ sheath. Tillaux's
account is thus far perfectly correct. In like injuries
which I have followed up in rabbits, the so-called
fatty alteration of the nerve progressed exactly as in cases
of section, save that it was more or less complete as the
original injury was more or less destructive, many fibres
in the latter case escaping change altogether.
I was impressed, however, with a fact which finds
ample clinical illustration. In some cases where I struck
the nerve smartly with a smooth, broad whalebone slip,
allowing a thin layer of muscle to intervene, the paralysis
which ensued, although often temporary, w^as in degree
complete. In these instances there was usually little
hemorrhage, but a few fibres were torn, and a large proportion
suffered simply a mechanical disturbance, which
gave them for the time a baccated look and irregularities
of outline, due to displacement of their semi-fluid contents.
If a nerve, disturbed only to this degree, be examined
within a few days, when the paralysis is no longer
discernible, the nerve tubes present but very slight traces
of mechanical alteration, and a still later inspection rarely
shows greater alteration of the nerve save in a very few
fibres.
It is therefore probable that the condition described is
one which is for the most part rapidly repaired, and that
the temporary symptoms which follow slight nerve con-
be due to the definite mechanical disturbance
tusions may here spoken of.