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

VARIETIES OF MECHANICAL INJURIES OF NERVES. 99
no careful
examination has been made as to the nervous
condition, so that when, after reduction, the arm appears
paralyzed, the surgeon is apt to refer it to the last disturbing:
cause, and not to the accident.
.— Dislocation causing nerve mjury That dislocation of the
humerus should sometimes cause paralysis is not surprising,
since even a severe blow upon the shoulder is competent
to tins result, as every surgeon well knows. Cases
of this nature are related by Cansard, and I have faradised
two patients for injuries thus produced.
Without following further the classical discussions upon
this accident, it will be suthcient to state the opinions
which I have reached after careful examination.
In the first place, falls on the shoulder or on the hand
being competent to cause palsies of the arm, we may expect
to meet with the latter even ia such cases of dislocation
as put out of the question any possible compression of
nerves by the head of the humerus. In dislocation of the
humerus backward, a rare accident, no nerve lesion is
likely to occur. In luxation downward into the axilla,
the capsule
is of course torn, the muscles and tendons are
bruised and elongated, and the circumflex nerve, extremely
liable to injury from its close relation to the capsule, is very
apt to be torn or stretched. This latter lesion, which has
been actually found post mortem, is the cause of the atrophy
of the deltoid which sometimes ensues. Hamilton
thinks that the muscular loss is often due to the mere
contusion of the deltoid; but on the whole it is more in
accordance with modern views to see in the atrophy a consequence
of nerve lesion, of which rheumatic or scrofulous
inflammations of the joint are so apt to furnish examples.
In dislocations of the humerus under the coracoid process,
or under the clavicle, the circumflex nerve and the
muscles about the joint are prone to sutt'er severely, while
the brachial nerves are liable to be carried forward with