STRUCTURAL EXAMINATION 39 



that forms the pastern and below this there are two others 

 continuing the slope of the pastern; while the fourth is 

 located at the juncture of the two just mentioned. It is evi- 

 dent that it is desirable for the pastern bone to slope at least 

 forty-five degrees, for if it is straighter than this, the concus- 

 sion given to the foot is not dissipated over all the structures 

 as it should be. A horse putting the foot down (except 

 when severely taxed in draft and then the toe reaches the 

 ground first) receives the concussion on the frog which trans- 

 mits it to the tendinous tissue padding the heel of the foot. 

 From there it passes to the bones of the foot apparently 

 about the region of the first joint made by the three bones, 

 the navicular, coffin and the coronary, which are admirably 

 arranged in the leg having a sloping pastern to each receive 

 a share of the buffeting. If the pastern is sloping it would 

 seem that only a small part of the concussion is likely to 

 reach the pastern bone and this seemingly would be com- 

 pletely spent before the fetlock joint would be reached. This 

 joint when the pastern slopes properly, swings in a sling ot 

 ligaments and tendons and consequently when the parts 

 below slope considerably, it is much more effective in pro- 

 tecting the bones of the leg from the irritation that arises 

 from concussion. It is easy to see why navicular disease, 

 ridebones and ringbones, are most frequently associated 

 with straight pasterns. The concussion from the foot in the 

 straight pastern falls most severely on the first joint formed 

 by the navicular, coffin and coronary bones and consequently 

 it is about this region that these various bone diseases are 

 located. Concussion produces irritation, which continued 

 results in inflammation followed by bony deposits. To give 

 the pastern the proper springiness, a proportionate length 

 should be associated with the slope. The slope however, is 

 of still more importance than length or size. The features 

 of the joints at both ends should be clearly defined, showing 



