3862 DISEASES OF THE HORSE, 
Sometimes a bone is fractured in the immediate vicinity of a joint. 
The knowledge of this fact requires us to be able to diagnose between 
a dislocation and such a fracture. In this we generally have three 
points to assist us: (1) The immobility of a dislocated joint as 
against the apparently remarkable freedom of movement in frac- 
ture; (2) in a dislocation there is no true crepitus—that peculiar 
grating sensation heard as well as felt on rubbing together the rough 
ends of fractured bones; however, it must be remembered that in a 
dislocation two or ‘Hives, days old the inflammatory changes around 
the joint may give rise to a crackling sensation similar to that in 
fracture; (3) asa rule, in luxations, if the ligamentous and muscular 
tissues about the joint are not badly torn, the displacement, when re- 
duced, does not recur. 
Prognosis —The prognosis of a luxation is comparatively less seri- 
ous than that of a fracture, though at time the indications of treat- 
ment may prove to be so difficult to apply that complications of a 
very severe character may arise. 
Treatment.—The treatment of luxations must, of course, be similar 
to that of fractures. Reduction, naturally, will be the first indica- 
tion in both cases, and the retention of the replaced parts must fol- 
low. The reduction involves the same steps of extension and counter 
extension, performed in the same manner, with the patient subdued 
by anesthetics. 
The difference between the reduction of a dislocation and that of a 
fracture consists in the fact that in the former the object is simply to 
restore the bones to their true, normal position, with each articular 
surface in exact contact with its companion surface, the apparatus 
necessary afterwards to keep them in situ being similar to that which 
is employed in fracture cases, and which will usually require to be 
retained for a period of from 40 to 50 days, if not longer, before 
the ruptured retaining ligaments are sufficiently firm to be trusted 
to perform their office unassisted. A variety of manipulations are 
to be used by the surgeon, consisting in pushing, pulling, pressing, 
rotating, and, indeed, whatever movement may be necessary, until 
the bones are forced into such relative positions. that the muscular 
contraction, operating in just the right directions, pulls the opposite 
matched ends together in true coaptation—a head into a cavity, an 
articular eminence into a trochlea, as the case may be. The “setting” 
is accompanied with a peculiar, snapping sound, audible and signifi- 
cant, as well as a visible return of the surface to its normal sym- 
metry. 
Special dislocations.—While all the articulations of the body are 
liable to this form of injury, there are three in the large animals 
which may claim a special consideration, viz: 
