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

38 INJURIES OF NERVES.
sometimes abnormal in character;
meanwhile the irresfular
and retarded circulation fails to remove these products
with even the normal rapidity, and their accumulation
may come to act as local poisons to limited regions of
tissue, and so be efficient in bringing about the diseased
conditions of which I have spoken.
The most interesting generalizations as to trophic
changes consequent upon lesions of nerve trunks are
these :
Total section of the main nerves of a limb results
invariably in atrophy, but not necessarily in any inflammatory
conditions. It does not, however, forbid these,
nor is repair always interfered with to any great extent.
Partial wounds of nerves, and especially gunshot
lesions,
are apt to give rise to a large number of trophic
changes in the skin, hair, nails, areolar tissue, and muscles.
Except the entire arrest, for a time, of nail growth, every
trophic alteration capable of arising from injuries or diseases
of the centres is also to be met with as a consequence
of wounds of the nerves.
Section of muscle nerves causes atrophy and contraction
of the related muscles. Partial wounds occasion
various degrees of wasting, with more or less loss of muscular
sensation, and impairment or loss of power to respond
to electric, galvanic, or mechanical irritation.
Exceptional cases exist of atrophy without defect of excitability
under stimulation.
Trophic changes in the skin, hair, and nails are never
present after nerve wounds without some affection of sensation,
such as dysasstbesia, anaesthesia, or hyperpesthesia;
but any of these latter states may exist without the nutritive
alterations in question.
Trophic changes are most prone to follow wounds of
nerves which are distributed to the hands and feet, and
more rarely occur when the injury has involved only the