OSSIFICATION OF THE LATERAL CARTILAGES. 219 



lameness at the time or not, the animal is to be classed as 

 unsound, for the reason that, on being put to fast or road 

 work, especially where there are hard roads, lameness will 

 appear. Hard work will cause sidebones, and going faster 

 than a walk tends to produce it in heavy draught horses. 

 The plough horse that goes in the furrow frequently suffers. 

 The most prolific cause in light horses is fast work, and 

 more particularly when on hard roads. Sidebones may also 

 be caused by injuries, as a tread, bruise, puncture, etc., by 

 which the lateral cartilages are injured, causing inflamma- 

 tion to become established in the parts, and the various 

 changes to take place which result in ossification. 



Symptoms. — Sometimes the inflammation is of a very 

 mild character, and the process of ossification very slow, in 

 which case ossification of the lateral cartilages may take 

 place without any appreciable lameness or irritation ever 

 having been observed. But such a case is the exception 

 and not the rule. The condition is oftenest met with in 

 the fore-foot, very seldom occurring in the hind limb. In 

 some instances the cartilage becomes considerabl}'' enlarged, 

 giving rise to an external enlargement, which may be easily 

 seen; in other cases no visible enlargement can be detected. 

 On manipulation, the cartilage, which in health is very 

 flexible, is found to be inflexible, hard, and unyielding to 

 the touch. During progression the toe of the foot is first 

 brought to the ground, and there is — in case both fore feet 

 are involved — a peculiar stilty action and stiffness of gait, 

 somewhat resembling that of navicular arthritis. There is 

 also, during the inflammatory stage, great heat and tender- 

 ness of the parts, especially where the animal is worked or 

 the exciting cause kept up. In some cases suppuration may 

 occur. After ossification is comj^leted, the sidebones are 

 liable to fracture the same as any other osseous structure. 

 In certain cases, ossification of the lateral cartilages gives 



