15. Here, as in all other fractures, the means of reduction must be
founded on the causes of displacement. To effect the replacement,
therefore, it is necessary, either to push backward and downward, the
angle which is displaced in a contrary direction, in order that it may
be brought into contact with the body of the bone, or else to draw the
body of the bone forward and upward, that it may meet the displaced
angle. It is thus, that in a fracture of the condyle, the body of the
jaw, is drawn into contact with the fragment.
16. But the first mode of reduction is difficult, and the means of
maintaining it impracticable. It is necessary, therefore to have
recourse to the second, which is the more easily executed, as the
scapula follows the movements of the arm, and as, by drawing this limb
forward, and the elbow of it outward, that bone is removed from the
spinous processes of the vertebræ, and directed in such a manner, as
to be brought into contact with its inferior fragment. This situation
possesses another advantage, as it throws into a state of relaxation
the muscles which tend to displace the lower fragment.
Hence it follows, 1st, That here, in like manner as in fractures of the
clavicle, it is not on the fractured bone, that the force must act, but
on the humerus. 2dly, That the humerus ought to be, during the whole
treatment, immoveably fixed, because its motions, being communicated to
the scapula, must soon derange the contact necessary to a reunion.
18. On these principles were founded the apparatus of Desault, and his
process of reduction, which consisted, 1st, in drawing the arm forward,
and separating the elbow a little from the thorax; 2dly, in fixing the
fore-arm at an angle sufficiently acute, to direct the hand to the
point of the opposite shoulder; and 3dly, to bring afterwards into
proper apposition and form, the fragments already approximated to each
other by the first movements.
19. To retain this reduction, the arm and fore-arm must be permanently
fixed in the above position. This object is attained in the following
manner, 1st, A bolster in form of a wedge, being placed between the
arm and the side, its apex situated in the arm-pit, affords the double
advantage of keeping the elbow at a distance from the thorax, and of
rendering the position of the arm less fatiguing by serving as a point
of support to it. 2dly, Compresses wet with some discutient liquid,
are applied on the part corresponding to the fracture. 3dly, The whole
is now to be secured by a roller, seven or eight yards long. The first
turns of this roller, must secure the hand of the affected side on the
sound shoulder to which it had been applied, during the reduction,
and running afterwards from before backwards, pass over the place
of the fracture, for the purpose of retaining the compresses on it.
The wedge-formed bolster is to be secured on the thorax, by circular
turns around it. Then, passing under the sound arm-pit, after having
made these circular turns, the roller must be brought behind again,
conducted obliquely over the shoulder of the diseased side, along the
anterior part of the arm, under the elbow, and behind the thorax,
where it is carried obliquely, in order to pass again under the sound
arm-pit. From this place it ascends again anteriorly over the affected
shoulder, redescends along the posterior part of the arm, repasses
under the elbow, returns under the arm-pit, and terminates finally
in circular turns round the trunk, and arm together. Hence it may be
observed, that, in the first turns of the roller, this bandage greatly
resembles the third roller applied in the fracture of the clavicle, to
retain the point of the shoulder upward and backward (Fig. 4. plate I.)
20. By this, 1st, The movements of the arm being entirely impeded,
they cannot have any influence on those of the shoulder; hence, in
this respect, the fragments are suffered to remain in contact. 2dly,
The serratus-major and teres-major muscles, being kept in a state of
habitual relaxation, can no longer draw the inferior fragment forward,
which cannot, therefore, be separated from the body of the bone.
3dly, Nor can the body of the bone, being permanently held in this
situation, be removed from the fragment; whence, in both respects, a
displacement will be effectually prevented. This threefold advantage
is not possessed by any of the different kinds of apparatus hitherto
proposed, such as the sling and cross-bandage, employed by Petit, which
have the fault of suffering the arm to move backward, of allowing the
scapula to be easily separated from its insulated angle, of retarding
by that means the cure, and even of preventing it entirely, while, by
the process just described, it is usually completed by the thirtieth
day.