SPRAINS TO JOINTS, TENDONS, AND LIGAMENTS 289 



SPRAINS TO JOINTS, TENDONS, AND LIGA.AIENTS 



The severe etibrts wliicli horses are called upon to make, and often 

 under the most trying circumstances, render them specially liable to 

 overtax the muscles, tendons, ligaments, and joints of the extremities, 

 or in other words unduly stretch or strain them. Sprain is one of the 

 most common ailments affecting the legs of horses. It may consist in 

 a mere overstretching of the fibres of a structure, or some may at the 

 same time be ruptured. 



Its origin cannot be considered altogether apart from conformation, 

 for it is found that any considerable departure of the legs from the 

 perpendicular tending to disturb the centre of gravity has the effect of 

 unequally distributing the weight of the body, and predisposing certain 

 parts on which it falls in excess to sprain. Knees in-bowed or out-bowed, 

 knees set unduly backwards, feet turned outward or inward, cow hocks, 

 and various other defects of conformation are conditions favourable to 

 this accident. 



Big joints, besides providing a large surface of support to diffuse and 

 minimize concussion, are also furnished with large strong ligaments by 

 which they are able to resist sprain, while small joints, whose connecting 

 structures are wanting in substance and strength, more readily yield to the 

 force applied to them. 



These unfavourable conditions are aggravated when left out of con- 

 sideration in the operation of shoeing. When one part of the crust is 

 unduly lowered beyond another the already unecjual distribution of the 

 weight on the structures which bear it may be materially increased. 



Narrow, leggy horses, which lack staljility owing to their narrow base 

 of support, are rendered liable to sprain by their tendency to slip. 



The exciting causes of sprains consist in violent extension of the 

 structures involved; but Williams observes "extension is not always the 

 cause of a strain, as a muscle may be injured by the opposite condition, 

 namely, violent contraction, its fibres and their thccte broken across 

 their long axes, or its tendinous fibres torn from their attachments at 

 either or both of its extremities". 



Slips and false steps, severe efforts at draught, or in the gallop or 

 jumping, or in struggling to remove a limb from a fixed position, are 

 causes of the Aiolent extension from which sprains result. 



Symptoms. — These will vary with the structure affected. Generally 

 they comprise lameness, tenderness of the part with or without swelling, 

 resting of the limb in such a way as to relieve tension and take the weight 



Vol. II. 53 



