866 FRACTURES OF THE PHALANGES. 



Luxation may occur spontaneously, or without any particularly 

 violent effort. A pure-bred st a 1 lion showed very severe lameness alter- 

 nately in both hind legs. Rheumatism was suspected and treatment 

 directed accordingly. One morning the horse was found lying down 

 with the left hind fetlock luxated. On being approached to apply 

 a bandage, the horse attempted to rise and luxated the other fetlock. 

 On post-in. .item, the extensor and flexor tendons were found intact 

 hill the synovial capsules and lateral ligaments were ruptured. In 

 cases of this kind it is almost certain that inflammation or degenerat ive 

 changes must have previously occurred in the lateral ligaments. 



Johne gives the result of a post-mortem on a horse after luxation 

 of the os pedis, where the lower end of the os coronae had been 

 displaced backwards and outwards, and lay above the os naviculare. 

 The capsular ligament was consequently torn,, and the flexor perf orans 

 ruptured and inflamed. 



Treatment follows general principles. Reposition and control of 

 inflammation are, however, very difficult. Anaesthesia is generally 

 necessary before reduction can be effected. 



II.— FRACTURES OF THE PHALANGES. 



In the horse, fissures and fractures are commonest in the os 

 suffraginis, comparatively rare in the os corona? and os pedis. Such 

 fractures may be transverse, longitudinal or comminuted, simple 

 or compound. They are often the result of violent slips or sudden 

 turns, and therefore are especially frequent in race-horses. They 

 may also be caused by jumping or falling in races, but in addition 

 occur in heavy van-horses employed for slow draught, particularly 

 in winter when the roads are frozen. In riding-horses a frequent 

 cause is sudden turning, simultaneous fracture of the os suffraginis 

 in more than one limb being produced in this way. Roder saw in 

 a horse, transverse fracture of both front and of the right hind pastern 

 bones following a fall. Wentworth describes fracture of both front 

 pastern bones in a mare. Whether a peculiar predisposition existed 

 or whether the cause was the sudden strain thrown on the still intact 

 bone in consequence of the first fracture, could not, of course, be 

 decided. Tuson, in the above-described case, found a want of in- 

 organic substances in the fractured os suffraginis, but, somewhat 

 characteristically, gives no particulars of any analysis. In solipeds 

 generally, and race-horses in particular, fissure of the os suffraginis 

 is not infrequent. It was first noted in England, and Robertson 

 and Williams described split pastern as quite a common occurrence. 



