OSSIFICATION OF THE LATERAL CARTILAGE. SIDE-BONE. 



899 



Expansion of the hoof is always diminished, and may be entirely 

 suspended. Side-bones produce a clumsy, constrained action, and 

 at times lameness. The symptoms are aggravated by rapid work 

 on hard roads, by allowing the hoofs to become dry, and by using 

 high calkins. When, however, the hoof is kept moist, animals may 

 work for a long time without inconvenience. 



The diagnosis of side,-bone is easy as soon as the upper margin 

 of the cartilage has become ossified ; it then feels hard. On the 



Fig.513.— .4, Pedal bone; B, lateral Fig. 514.— Right fore foot. A, Coronet bone 



B, pedal bone ; G, outer lateral carti- 

 lage ; a, outer lateral ligament of pedal- 

 joint ; b, ligament connecting lateral 

 cartilage to coronet bone ; c, band 

 connecting lateral cartilage to pedal bone. 



cartilage cut through horizon- 

 tally at the level of the pedal- 

 joint; a, surface, formed by 

 pedal and navicular bones, for 

 articulation with coronet bone ; 

 b, postero-lateral ligaments of 

 navicular bone cut through ; 

 b ', portion of above which are 

 attached to back of navicular 

 bone. 



other hand, when ossification has only attacked the lower anterior 

 portion of the cartilage lying within the hoof, it is either very difficult 

 or absolutely impossible to detect the change, though the form of 

 the hoof sometimes gives valuable indications. 



The recognised causes are — (1) congenital predisposition, in 

 heavy, coarse-bred horses ; (2) excessive concussion produced by 

 work on hard roads, for which reason the disease is frequent in large 

 towns ; and occasionally, (3) shoeing with calkins, by which the 

 frog is prevented taking any bearing on the ground and the lateral 

 cartilages are subjected to a continuous inward and downward 

 dragging strain. This is concentrated at the fixed, i.e., anterior, 



