DISEASES OF THE HOESE. 337 



fractured bones; however, it must be remeuibered that in a dislocation- 

 two or three days old the inflanimator}- 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 displacement, when reduced^ does not recitr. 



Prognosis. — The prognosis of a luxation is comparatively less serious 

 than that of a fracture, though at times the indications of treatment 

 maj^ 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 fractuj-cs. Keduction, naturally, will be the first indicatiort 

 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 h& 

 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 bj^ the surgeon, consisting in pushing, pulling, pressing-, 

 rotating, and indeed whatever movement may be necessar}^, 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 ma}^ 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 S3'mmetr3\ 



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 nvdj escape 

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

 it— outward, inward, backward, or forward — and the deformity which 

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