CAUSE OF SPLINTS. 859 



3. By formation of extensive exostoses near the knee, which 

 interfere with free movement. The suggestion that lameness is 

 caused by the splint pressing on the suspensory or flexor tendons is 

 not well founded, though sometimes an exostosis is formed under 

 the suspensory on the posterior surface of the large metacarpal bone. 



In general, splints produce lameness, in the free limb (swinging 

 leg lameness) and abduction of the limb ; the knee is not fully flexed. 

 The lameness is better seen on hard than on soft ground, is much 

 more marked at the trot than at the walk, and is usually aggravated 

 by exercise. Weight is generally placed on the limb, and the hoof in 

 most cases is put down firmly and in the usual manner. The ex- 

 cessive tension in the fascia of the fore-arm during the last phase 

 of movement, just before the limb is lifted and during its extension, 

 causes painful jjressure on the inflamed periosteum. 



Abduction is particularly marked when the knee-joint is also 

 involved. Extensive exostoses interfering with movement of the 

 knee can be detected by passive movement ; attention is sometimes 

 drawn to them by the knee being held stiffly, and only partially 

 flexed during movement. 



(2) Local examination. The development of splint is characterised 

 by slight swelling, increased heat, and pain on pressure. The swelling 

 shows a certain degree of hardness, but in consequence of oedema of 

 the skin is at first of doughy consistence. This gradually disappears, 

 the swelling becoming firmer and harder. To detect pain the opposite 

 foot is lifted, and the hand placed with the thumb resting on the 

 outside, the fingers on the inner side, of the affected metacarpus. 

 By passing the fingers from above downwards, it is easy to estimate 

 the tenderness of the periosteum. To prevent mistakes, the same 

 process should be gone through with the sound limb. In practised 

 hands this examination is perfectly easy, though in some cases care 

 is required to avoid mistaking prominence of the ' w button " on the 

 small metacarpal for splint. On the other hand, inflammation of 

 the skin is sometimes difficult to distinguish from periostitis, though, 

 as a rule, painful lameness is here absent. Nevertheless, the other 

 portions of the limb should always be carefully examined in order 

 to confirm the diagnosis. This is particularly necessary when the 

 pain produced by pressure is slight. 



Prognosis is generally favourable, especially where the position 

 and character of the splint point to mechanical injury. Exostoses 

 of a longish form occurring on the small metacarpal and in young 

 horses are apt to be troublesome. The chance of recovery is less 

 if, in consequence of defective formation of the limb, the parts are 



