lameness: its causes and tbeatment. 361 



One of the essentials of treatment, and probably an indispensable 

 condition when recovery is in any wise attainable, is the suspension 

 of the patient in slings. He should be continued in them so long as 

 he can be made to submit quietly to their restraint. 



DISLOCATIONS. 



Dislocations and luxations are interchangeable terms, meaning the 

 separation and displacement of the articulating surfaces of the bones 

 entering into the formation of a joint. This injury is rarely en- 

 countered in our large animals on account of the combination of 

 strength and solidity in the formation of their joints. It is met with 

 but seldom in cattle and less so in horses, while dogs and smaller 

 animals are more often the sufferers. 



Cause. — The accident of a luxation is less often encountered in the 

 animal races than in man. This is not because the former are less 

 subject to occasional violence involving powerful muscular contrac- 

 tions, or are less often exposed to casualties similar to those which 

 result in luxations in the human skeleton, but because it requires the 

 cooperation of conditions — anatomical, physiological, and perhaps 

 mechanical — ^present in the human race and lacking in the others, 

 which, however, can not in every case be clearly defined. Perhaps 

 the greater relative length of the bony levers in the human forma- 

 tion may constitute a cause of the difference. 



Among the predisposing causes in animals may be enumerated 

 caries of articular surfaces, articular abscesses, excessive dropsical 

 conditions, degenerative softening of the ligaments, and any exces- 

 sive laxity of the soft structures. 



Symptoms and diagnosis. — Three signs of dislocation must usually 

 be taken into consideration. They are: (1) An alteration in the 

 shape of the joint and in the normal relationship of the articulating 

 surfaces; (2) an alteration in the length of the limb, either shorten- 

 ing or lengthening; (3) an alteration in the movableness of the joint, 

 usually an unnatural immobility. Only the first, however, can be 

 relied upon as essential. Luxations are not always complete; they 

 may be partial; that is, the articulating surfaces may be displaced 

 but not separated. In such cases several symptoms may not be 

 present. And not only may the third sign be absent, but the mobility 

 of the first be greatly increased when the character of the injury has 

 been such as to produce extensive lacerations of the articular 

 ligaments. 



In addition to the above signs, a luxation is usually characterized 

 by pain, swelling, hemorrhage beneath the skin from damaged op 

 ruptured blood vessels, and even paralysis, when important nerves 

 are pressed on by the displaced bones. 



