STRUCTURAL EXAMINATION 39 



small bones below the fetlock joint. The first one below 

 this joint is the one that forms the pastern and below this 

 there are two others continuing the slope of the pastern ; 

 vrhile the fourth is located at the juncture of the two just 

 mentioned. It is evident that it is desirable for the pastern 

 bone to slope at least forty-five degrees, for if it is 

 straighter than this, the concussion 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 transmits it to the ten- 

 dinous 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 completely 

 spent before the fetlock joint would be reached. This 

 joint when the pastern slopes properly, swings in a sling 

 of 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, 

 sidebones 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 pro- 

 portionate length should be associated with the slope. The 

 slope, however, is of still more importance than length or 



