456 



THE EXTERIOR OF THE HORSE. 



employment is still more diffieiilt, for, not having perfect freedom in 

 the use of his fore-limbs, and l)eing })redisposed to stumble, he exposes 



his rider to falls which may prove 



Fig. 162. 



serious on rough and uneven roads. 



b. Axes of the Posterior Members. 



Axes viewed in Profile. — The 

 ])rinciple which we have employed to 

 estai)lish the axes of the anterior mem- 

 ber admit of a much sim})ler a})plica- 

 tion when referred to the posterior 

 member. The centre of suspension of 

 the latter upon the trunk is known to 

 us with sufficient accuracy ; it is the 

 coxo-femoral articulation. \Ye may 

 therefore conclude that the direct axis 

 of the posterior column will be in a 

 good position if the digital extremity 

 of this column is stationed at the bot- 

 tom, d (Fig. 162), of the vertical line 

 which pas.ses through the articular cen- 

 tre, c. In fact, it is this which obser- 

 vation demonstrates in horses of good 

 equilibrium of the posterior quarters ; 

 a plumb-line placed at the level of the 

 joint in question divides the hoof into 

 two equal parts. 



As in the anterior member, and for the 

 same reasons, the vertical line, cd, is also 

 equidistant from the perpendiculars to the 

 ground, ot and sp, or also ef and jh. It 

 intersects the leg, os, as well as ej, at its 

 middle. If the tarso-metatarsal segment 

 remain vertical, the horizontal projection, 

 fp, of the leg is double the horizontal projec- 

 tion, (Ij), of the phalangal segment. Finally, 

 any degree of opening of the angles will be 

 compatible with good axes, on condition 

 that the articular angles maintain their 

 summits upon the vertical lines of and sp. 



The axes of the hind-limbs are based, as is seen, upon the same 

 principles as those of the fore-limbs. The four locomotory columns, in 



