CAUSE OF SPLINTS. 
589 
Lameness is less common in coarse-bred than in well-bred horses. 
When periostitis is caused by mechanical injury, lameness disappears 
with its subsidence, and only returns if the injury be repeated. In 
such cases it lasts about three weeks. Partial rupture of the inter¬ 
osseous ligament recurs very easily, causing the lameness not only to 
continue for longer periods, but also to return, and therefore splints of 
a longish shape occurring on the small metacarpal continue to interfere 
with the animal’s usefulness for a long time, frequently for many 
months. In periostitis near the knee there is danger of inflammation 
extending to the knee-joint; the lameness then continues for longer 
periods, sometimes indeed becomes chronic, from changes in the knee 
producing arthritis deformans, and from mechanical interference with the 
mobility of the joint by large exostoses in its immediate neighbourhood. 
Splints at this point following on injury often produce chronic lameness. 
Lameness may therefore be caused— 
1. By periostitis. 
2. By inflammation of the knee-joint. 
8. By formation of extensive exostoses near the knee, which interfere 
with free movement. The idea that lameness is caused by the splint 
pressing on the flexor tendons is erroneous. 
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 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 excessive 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 
pressure 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 periostitis 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 
