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

150 INJURIES OF NERVES.
disappears, the skin becomes dry, ragged, yellowish or
brown, and rough;
tlie nails and hair degenerate, while
the veins shrink and the arterial pulse grows feeble.
Lesser nerve injuries produce, of course, muscular atrophies
bearing a proportion
to the fibres wounded or cut.
Where a missile has divided a nerve, wholly or in part,
these changes beo-in in the connected muscles with a
slight but almost immediate loss of tension, so that the
muscle feels iiabby and relaxed.
This is certainly the first notable alteration in a muscle
the nerves of which have been severed. It is so perceptible,
within a day or two of the injury, that in some cases
it is possible to tell, by handling the part, what muscles
are thus isolated and what are not. Within a few hours
there is, in the disordered muscle, some loss of power to
move when faradised, and the difhculty increases day bj'
da}', until finally it ceases altogether to respond to this
form of stimulation. For a much longer time, perhaps
even for weeks or months, the same muscle may move
more or less readilj' when traversed by a current of twenty
to forty galvanic cells, while it is also noticeable that
mechanical irritation may produce contractions long
after induced currents have ceased to possess any such
power.
The pathological
changes which accompany
this functional
deficiency have been frequently described as fatty
degeneration but they scarcely deserve this description.
;
The following extract from Vulpian so precisely corresponds
to the alterations which I have myself seen and
studied, as to require no additions :
" Muscular atrophy from nerve section is characterized
by a considerable reduction in the diameter of the primitive
muscular bundles, accompanied in a few localities by
granular fatty changes, with total disappearance of certain
fibres. In the early stages of alteration, the primi-