358 THE STIFLE. 



necessary to repeat the blister, while absolute rest should accompany every 

 stage of the treatment. It may even be requisite to fire the part,— or, as a 

 last, resort, a charge may be placed over the joint, and the horse turned out for 

 two or three months. 



Proceeding from the body of the bone is a large irregular projection, rising 

 from a kind of pyramidal eminence (see p. 108), and into which are implanted 

 various powerful muscles. 



THE STIFLE. 

 The inferior extremity presents a pulley-like articulatory surface in front, 

 over which plays the patella, and two condyles, rounded and smooth, presenting 

 interiorly and posteriorly, and which are received into slight depressions on the 

 upper surface of the lower bone ; while in front is a curious groove, over which 

 plays a small irregular bone, the patella, or stifle bone. The whole is com- 

 monly called the stifle joint. The patella (Q, p. 108) answers to the kneepan 

 in the human subject. Some of the tendons of the strongest muscles of the 

 upper bone of the thigh are inserted into it, and continued from it over the lower 

 bone. This important joint is hereby much strengthened ; for the proper liga- 

 ments between the upper and lower bones, and these additional tendons and 

 ligaments from the patella, must form altogether a very powerful union. The 

 patella likewise answers another and even more important purpose. Thetendonsof 

 s jme strong muscles are inserted into it. When these muscles are not in action, 

 the patella lies in the groove which nature has contrived for it ; but when they 

 begin to contract, it starts from its partial hiding-place, becomes prominent from 

 the joint, and alters the line of direction in which the muscles act. It increases 

 the angle, and thus very materially increases the power of the muscles. 



The lower bone of the thigh is double. The larger portion, in front, extend 

 ing from the stifle to the hock, is called the Tibia. The smaller bone, on fibula, 

 behind (see R, p. 108), reaches not more than a third of the way down. It is 

 united to the shank bone, like the splint bone, by a cartilaginous substance, 

 which is soon changed into a bony one. Of the use of these little bones we 

 cannot speak. 



The lower bone of the thigh forms an angle with the upper one, being the 

 reverse of that which exists between the upper bone and the pelvis. The object 

 of this is twofold, — to obviate concussion, and to give a direction to the muscles 

 favourable to their powerful action ; and in proportion to the acuteness of the 

 angle, or the degree in which the stifle is brought under the horse, will these 

 purposes be accomplished. There is much difference in this in different 

 horses, and the construction of this part of the frame is a matter worthy of 

 more regard than is generally paid to it. 



This part of the thigh should likewise be long. In proportion to the length 

 of the muscle is the degree of contraction of which it is capable ; and also in 

 proportion to the contraction of the muscle is the extent of motion in the limb : 

 but it is still more necessary that this part of the thigh should have considerable 

 muscle, in order that strength may be added to such extent or compass of 

 motion. Much endurance would not be expected from a horse with a thin 

 arm. A horse with thin and lanky thighs will not possess the strength which 

 considerable exertion would sometimes require. In the cuts, p. 365 and 356, the 

 principal muscles of this part of the thigh are delineated. They are usually 

 somewhat prominent, and may readily be traced in the living animal : "a 

 very brief notice of them may not be uninteresting. 



The continuation from g, p. 356, is the tendinous expansion given to bind and 

 strengthen these muscles. 

 n is a very important muscle. It is the principal extensor muscle of the 



