262 OPERATIONS ON BONES. 



of plaster ot Paris, with a high shoe, as about the only indications 

 which science and nature are able to ofifer. When the fracture is 

 an occurred event, and the toes, one or more, are turned up, any 

 further resort to treatment will be futile. 



DISLOCATIONS. 



Strength and soUdity are so combined ia the formation ot the 

 joints of our large animals that dislocations or luxations are inju- 

 ries which are but rarely encountered. They are met with but 

 seldom in cattle and less so in horses, whUe dogs and smaller 

 anim.als are more often the sufferers. 



The accident of a luxation or (its synonym) dislocation (dis- 

 placement) is less often encountered in the aniCaal races than 

 in man. This is not because the former are less subject to oc- 

 casional violence involving powerful muscular contractions, or are 

 less often exposed to casualties similar to those which result in 

 luxations in the human skeleton, but because it requires the co- 

 operation of conditions, anatomical, physiological, and perhaps 

 mechanical, present in one of the races and lacking in the other, 

 but which can not in every case be clearly defined. Perhaps the 

 greater relative length of the bony levers in the human formation 

 may constitute a cause of the difference. 



Among the predisposing causes in animals, caries of articular 

 surfaces, articular abscesses, excessive dropsical conditions, de- 

 generative softening of the Ugaments, and any excessive laxity of 

 the soft structures, may be enumerated. 



The symptoms of fractures and of dislocations are not always 

 so variant as to preclude the possibility of error in determining a 

 case without a thorough examination, but the essential difference, 

 as it must always exist, must always be discoverable. 



In a dislocation there is one very pecuhar and characteristic 

 feature in the impossibility of motion associated with an excessive 

 liberty of movement — the impossibility of active or controlled 

 motion, and a facUity of passive movement (or movableness) at 

 either the affected joint or at another of the same leg near to it. 

 In a dislocation of the scapulo-humeral (or shoulder) joint the 

 animal possesses no power of motion over the limb — ^no muscular 

 contraction can avail to cause it to perform, its various functions 

 — but in the hands of the surgeon it may be made to describe a 



