ELEMENTS OF HIPPOLOGY. 113 



great strength and mass, and its position and movements are 

 entirely obscured by them. The thighs should be well filled up, 

 viewed from behind, leaving no open space between the legs. 

 The stifles should be slightly wider apart than the hips, to insure 

 freedom of movement in the stride. 



The stifle, or patella, corresponds to the human knee-cap. 

 Its function is to afford additional leverage to certain muscles 

 that advance the leg. It lies in front of the stifle-joint, and is 

 held in place by several ligaments. Dislocations of the patella 

 are rare, but are much more frequent than dislocations of any 

 other joint. A horse suffering from this dislocation is said to 

 be stifled. 



The leg-bone, or tibia, lies between the stifle-joint and the 

 hock. The lower part of the muscles of the tibia is termed the 

 gaskin, and it is important for fast work that these muscles be 

 well developed. The muscles of the thigh start the propulsion; 

 it is accelerated by the upper muscles of the tibia and the muscles 

 of the gaskin give the final impulse to the stride. They are 

 smaller and shorter than the upper muscles of the hind leg and 

 their action correspondingly quicker. It is therefore important 

 that their development be considerable. 



Aside from the rare dislocations of the patella, and fract- 

 ure of the points of the hips, there are no common injuries 

 to be looked for in the region of the hind leg, above the hock. 

 This joint, however, is very liable to be disabled by an obscure 

 disease, often difficult to discover, and always, when existing, 

 of a nature that makes the animal permanently unsound. This 

 disease is bone spavin. 



The hock is a more complicated joint than the knee. It 

 is composed of six bones, five of which are interposed between 

 the tibia and the cannon-bone, and a sixth placed behind them 

 to act as a lever for certain of the tendons of the leg. In Figure 

 77 the cannon-bone is the bone at the bottom of each drawing. 

 The tibia, leg-bone, is entirely removed. It articulates with the 

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