16 MOUNTED INSTRUCTION 



Toe Cracks: Are most common in the hind feet, while quarter 

 cracks nearly always affect the fore feet. The inside quarter is more 

 liable to the injury than the outside, for the reason that this quarter 

 is not only the thinner, but during" locomotion receives a greater part 

 of the weight of the body. A sand crack may be superficial, involving 

 only the outer parts of the wall, or it may be deep, involving the whole 

 thickness of the wall and the soft tissues beneath. 



The toe crack is most likely to be complete — that is, extending from 

 the coronary band to the sole — while the quarter crack is nearly al- 

 ways incomplete, at least when of comparatively recent origin. Sand 

 cracks are most serious when they involve the coronary band in the 

 injury. They may be complicated at any time by hemorrhage, in- 

 flammation of the laminse, suppuration, gangrene of the lateral carti- 

 lage and of the extensor tendon. Relative dryness of the horn is 

 the principal predisposing cause of sand cracks. Heavy shoes, large 

 nails, and nails set too far back toward the heels, together with such 

 diseases as canker, quittor, grease, and suppurative corns, must be in- 

 cluded as occasional causes of sand cracks. 



Sidebones: A sidebone consists in a transformation of the lateral 

 cartilages found on the wings of the cofifin bone into bony matter by 

 the deposition of lime salts. The disease is a common one, especially 

 in heavy horses used for draft, in cavalry horses, cow ponies, and 

 other saddle horses, and in runners and trotters. 



Sidebones are peculiar to the fore feet, yet they occasionally de- 

 velop in the hind feet, where they are of little importance since they 

 cause no lameness. In many instances sidebones are of slow growth 

 and, being unaccompanied with acute inflammation, they cause no 

 lameness until such time as, by reason of their size, they iifterfere 

 with the action of the joint. Sidebones often grow in heavy horses 

 without any apparent injury and their development has been at- 

 tributed to the overexpansion of the cartilages caused by the great 

 weight of the animal. Blows and other injuries of the cartilages 

 may set up an inflammatory process which ends in the formation 

 of these bony growths. High-heeled shoes, high calks, and long' feet 

 are always classed among the conditions which may excite the 

 growth of sidebones. They are often seen in connection with con- 

 tracted heels, ringbones, navicular disease, punctured wounds of the 

 foot, quarter cracks, and occasionally as a sequel to founder. 



Ringbones: Is the growth of a bony tumor on the ankle. This 

 tumor is, in fact, not the disease, but simply the result of an inflam- 

 matory action set up in the bone tissue proper of the pastern bone. 



Injuries such as blows, sprains, overwork in young, undeveloped 

 animals, fast work on hard roads, jumping", etc.. are among the princi- 

 pal exciting causes of ringbone. Horses most disposed to this disease 

 are those with short, upright pasterns, for the reason that the shock 

 of locomotion is but imperfectly dissipated in the fore legs of these 

 animals. Improper shoeing such as the use of high calks, too great 



