LAMENESS AND DISEASES, ETC. 



189 



axis of the coffin bone to 

 the ground, which indi- 

 cates the perfect poise of 

 the coffin bone when the 

 foot is at rest. This 

 is the crucial test of a 

 foot both level and bal- 

 anced. If the coffin bone 

 is out of position with 

 reference to the median 

 line, B, B, the entire foot 

 and limb are out of bal- 

 ance. The journals of 

 the joints at the ankle 

 and knee do not articu- 

 late in equilibrio, and the 

 tendons and ligaments are 

 unduly taxed or relieved, 

 dependent upon which 

 side of the hoof bears an 

 undue strain. The ac- 

 companying drawings will illustrate this point. Fig. 81 shows 

 the proper position. Fig. 86, with the vertical dropping through 

 the apex of hoof, is the reproduction of a perfect coffin bone, 

 photographed from nature. The line of pressure was thrown, 

 back from its correct vertical position by an undue length 

 and height of the wall at the toe (see Fig. 82). The reverse 

 result is obtained by an excessive height of the heel, as shown 

 in Fig. 85. In the one instance a preponderance of the weight 

 is thrown upon the flexors, and in the other upon the extensors; 

 and in both cases depriving the bone structure of the limb of 

 its primary function of being the organic weight bearer. 



The practical result of thus placing the foot out of line 

 with reference to the vertical position of the cannon bone, and 



Fig. 81. coffin bone. 

 Lateral view — correct position. 



