274 DISEASES OF BONE. 



(p. 675). For further information on this subject see " The Veteri- 

 nary Record," 21st December, 1896, Eccles's " The Practice of 

 Massage," and Moller's work. Stiffness of the knee may be 

 similarly combated. 



Sidebones. 



NATURE. — Sidebones is the term used to express an ossified 

 condition of the lateral cartilages. The ossification may be partial 

 or complete, and may afiect both cartilages, or only one. The 

 lateral cartilages are plates of cartilage mixed with fibrous tissue 

 which, on each side, are attached to and placed above the wings 

 of the pedal bone. They may be looked upon as cartilaginous and 

 fibrous prolongations, above and to the rear, of the wings of the 

 pedal bone. Fig. 105 gives a representation of a pedal bone 

 from which the lateral cartilages have been removed ; and Fig. 106, 

 that of the same pedal bone with these cartilages intact. In Fig. 

 107, which is a transverse and vertical section of a horse's foot, thfe 

 lateral cartilages can be seen as white curves. Each cartilage in 

 an ordinary saddle-horse is about 3 inches long, J inch in thickness, 

 and is about 1| inches high at the end of the wing of the pedal 

 bone, behind which it projects for about 1^ inches. These carti- 

 lages, which are peculiar to the horse family, are attached to 

 the plantar cushion (Figs. 61 and 70), a fibrous and more or less 

 elastic body that acts as a buffer between the frog and the bones 

 which are above it. The lower part of the plantar cushion is 

 covered by the sensitive frog, which is a membrane tha,t secretes 

 the frog. The lateral cartilages are more largely developed in the 

 fore feet than in the hind feet. When these cartilages are ossified, 

 they usually present more or less the appearance shown in Figs. 108 

 and 109. Sometimes only the front part of the cartilage (at the 

 quarters) becomes ossified, as in Fig. 110, in which case the carti- 

 lages at the heels preserve their elasticity. 



OCCURRENCE. — Sidebones are almost always confined to the 

 fore feet; and in the majority of cases affect only cart-horses. I 

 may say that at least 50 per cent, of heavy draught animals 

 in large towns in England and Scotland suffer from them. The 

 outer cartilage is more frequently affected than the innet ; and, 

 according to Lungwitz, the near fore foot, than the off fore. 

 Sidebones are rarely seen in young horses which have not been put 

 to work. 



CAUSES. — The chief causes of sidebones appear to be : (1) de- 

 privation of frog pressure ; and (2) injury. High calkins, the use 

 of which is almost entirely confined to cart-horses, deprives the 



