DISLOCATIONS. 337 



fractured bones; however, it must be remembered that in a disloca- 

 tion two or three days old the inflammatory changes around the joint 

 may give rise to a crackling sensation similar to that in fracture; (3) 

 as a rule, in luxations, if the ligamenous and muscular tissues about 

 the joint are not badly torn, the displaceTnent, when reduced, does 

 not recur. 



Prognosis. — The prognosis of a luxation is comparatively less seri- 

 ous than that of a fracture, though at times the indications of treat- 

 ment may prove to be so difficult to apply that complications may 

 arise of a very severe character. 



Treatment. — The treatment of luxations must, of course, be similar 

 to that of fractures. Reduction, naturally, will be the first indication 

 in both cases, and the retention of the replaced parts must follow. 

 The reduction involves the same steps of extension and counter exten- 

 sion, 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 forty to fifty 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 

 employed 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 con- 

 traction, 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 by a peculiar snapping sound, audible and significant, 

 as well as a visible return of the surface to its normal symmetry. 



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 : 



THE SHOULDER JOINT. 



We mention this displacement without intending to imply the prac- 

 ticability of any ordinary attempt at treatment, which is usually 

 unsuccessful, the animal whose mishap it has been to become a victim 

 to it being disabled for life. The superior head of the arm bone as it 

 is received into the lower cavity of the shoulder blade is so situated as 

 to be liable to be forced out of place in four directions. It may escape 

 from its socket, according to the manner in which the violence affects 

 M. Doc. 795, 59-2 2Z 2 



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