The whole of the signs of a fracture of the neck of the humerus, taken
together, characterize its existence in a manner sufficiently evident.
But it is not always an easy matter to take a view of them all at once,
and in such a case, there are more difficulties attending the diagnosis
here, than in any other fracture of the humerus.
An acute pain is felt at the instant of the fall; and sometimes a crack
or report is plainly heard. There is always a sudden inability to move
the limb, which, being left to itself, hangs motionless. But if any
external force act on it, it yields to it without resistance, and may
be moved by it with great ease in every direction.
These motions are accompanied with severe pain, and, if carried too
far, may give rise to very troublesome affections, as has been observed
in patients, where the fracture was mistaken for a luxation.
Beneath the acromion, is discovered a depression, always situated lower
down, than that which accompanies the fracture of that apophysis. If
one hand be placed on the head of the bone, while the other is employed
in moving the lower fragment in different directions, or, while an
assistant, engaged in making the necessary extension, communicates to
this fragment a rotatory motion, 1st, the head will be perceived to
remain motionless; 2dly, the friction of the two divided ends will
produce a crepitation more or less perceptible. This twofold sign is
always decisive as to the existence of a fracture; but the swelling
of the joint may occasionally prevent the practitioner from availing
himself of it.
The fragments remain sometimes in contact, without experiencing
any displacement, in which case, most of the signs not manifesting
themselves, the diagnosis is rendered more difficult. But most
frequently a displacement occurs, and then it is the inferior fragment
that is deranged, and not the superior one which is so short that it
can be but little effected by the action of the muscles.
7. The displacement is in general but slightly perceptible in the
longitudinal direction of the bone, unless when, in a very oblique
fracture, the fragments present points which irritate the muscles,
excite them to contraction, and augment their force; or, when a blow
of great violence, continuing to act after the bone is broken, causes
the fragments to overlap each other. Thus has the body of the bone been
forcibly drawn upwards, or driven in the same direction, till having
passed through the deltoid muscle, and the external integuments, it has
even risen considerably above the level of its head.
But in general, as Petit observes, the weight of the limb hanging down
the side, opposes to the action of the muscles a sufficient degree
of resistance; and it is in the direction of the cross-diameter or
thickness of the bone, that the displacement most frequently occurs. It
is to be observed, that the lower fragment is driven either inward or
outward, rarely in any other direction. In the first case, which is by
far the most common, the elbow is somewhat removed from the body, and
cannot be brought near to it without pain; in the second, which is more
rarely met with, it is moved in an opposite direction.
In the one, the contractions of the deltoid muscle and the natural
curve of the humerus, in the other, the united action of the pectoralis
major, the latissimus dorsi, and the teres-major, appear to have an
essential influence on the displacement.
In each case, the displacement is facilitated by the mobility of the
lower fragment, and of the shoulder, when an apparatus from being
improperly constructed, fails to prevent the movements of the whole
extremity.
8. The signs which have just been detailed, do not always furnish such
luminous evidence, particularly to an inexperienced practitioner, as
to prevent the occurrence of very serious mistakes. Of this Desault
related many examples in his lectures.
CASE. J. M*** Est*** falling on his elbow, fractured the neck of the
humerus. A surgeon was immediately called, who, finding a depression
beneath the acromion, a protuberance in the hollow of the arm-pit,
and the humerus directed outwards, pronounced, without further
examination, that there existed a luxation in a downward direction.
Wishing to reduce it immediately, he employed, to no purpose, the
common processes. Acute pains were the consequence. The opening in the
capsule being too narrow was irritated, and the member subjected to
great violence of motion. At length the pains became insupportable; the
operators gave over their fruitless efforts, and Desault was called.
He discovered the mistake from the immobility of the head; from the
depression beneath the acromion being lower down than in a luxation;
and from the existence of a crepitation. A reduction was effected
without loss of time; the apparatus was applied, but in the evening
a considerable swelling occurred around the arm-pit; soon afterwards
inflammation was superadded; a vast collection of matter succeeded,
and, notwithstanding the utmost attention, it was five months before
the patient was restored to health.
9. To this example, I could add others, where the most serious
accidents have resulted from a similar mistake. It must be
acknowledged, however, that, if, in a fracture, the displacement be
inward and a little forward, the greater part of the signs herein
detailed (5) apply equally to a fracture and a luxation: but then, as
we have just seen in the preceding case, the immobility of the head,
the place of the depression beneath the acromion, and the crepitation,
will remove any doubts that may be excited in the mind of the surgeon,
by the protuberance in the arm-pit, the direction of the arm, &c. &c.
§ IV.