CHRONIC INFLAMMATION OF THE KNEE-JOINTS. 813 



their toes in the ground, and young race horses are often affected. 

 Not infrequently the disease is bilateral ; it is certainly more common 

 in coarse than in well-bred animals, and is favoured by putting young 

 horses to work too soon. Inflammation may extend from the 

 periosteum to the joint, particularly in horses with defective formation, 

 which are thus liable to " brush " in going, as is often the case in 

 Russian trotters. 



Symptoms. Swelling is the chief symptom, and is sometimes 

 so great that the entire knee may appear involved. The swelling 

 is usually hard and firm, consisting principally of new connective 

 tissue and later exostoses, but when the sheaths of the tendons are 

 involved, and become distended, it is soft and fluctuating. Free 

 movement of the joint is often interfered with. When resting, the 

 animals lean forward, and if forced to move go stiffly. Bending 

 the knee either produces pain or is attended with difficulty. 



Lameness may be well marked, or hardly noticeable. It occurs 

 oftener than is believed, and is shown by the limb being advanced 

 more slowly and the stride shortened, whilst the knee-joint is 

 imperfectly flexed and the limb abducted when weight is placed 

 on it. If both limbs be affected, or if the process be confined to 

 the lower portion of the joint, which in the horse is only slightly 

 movable, there may be no lameness. According to Cherry, such a 

 horse gives the rider the feeling that the thorax is pressed out of 

 position and rises with every stride. The condition is most liable to 

 be mistaken for navicular disease. The limb is extended, and turned 

 slightly outwards. The quarters of the foot often reach the ground 

 first, and on account of the peculiar gait the condition was in England 

 termed ' l chest founder." The pace naturally assumed is a short, 

 unpleasant trot, which shakes the rider. The forward stride of 

 the diseased limb is shortened, giving a certain resemblance to 

 shoulder lameness. The difference consists in — ■ 



(a) The circular sweep of the limb when moved forward. 



(6) In the horse bringing the quarter of the hoof to the ground 

 first. 



(c) In the production of pain by forcibly flexing the joint. 



Course. The nature of the disease explains why it is so often 

 chronic or incurable. The most favourable cases last from four to 

 six months, and it is therefore of great importance to know whether 

 or not the horse will afterwards be useful. The smaller the exostoses, 

 and the lower they are situated, the more favourable the prognosis. 

 The disease is, of course, not so serious in heavy working-horses 

 as in hacks. 



