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CHAPTER XI. 



Diseases of Bone, Joints, and Cartilage. 



general remarks splints enlargement op the splint bones—. 



sore shins ringbone bone spavin osteoporosis 



rickets rheumatoid joint disease stiff joints and knuck- 

 ling over sidebonbs. 



General Remarks. 



Inflammation of bone follows the same course as inflammation in other 

 tissues, allowing for diflference in structure. It may originate, as far as- I 

 can see : (1) from irritation due to the tearing away of the points of attach- 

 ment of the bone with tendon or ligament inserted on it ; (2) from direct 

 injury, as from blows ; (3) from indirect injury, as from concussion ; (4) 

 from compression ; (5) from changes brought on by chill, which changes are 

 generally ascribed to rheumatism ; and (6) from infection. Goubaux and 

 Barrier state that " it is important to remember that tumours of bones 

 which are the results of 'work,' appear. only at the points of insertion of 

 the great articular ligaments ; because it is at these particular points that 

 strain and distension impressed on the part, spreads to the periosteum 

 and sets up inflammation in it. The irritation extends gradually and soon 

 finishes by invading all the bony surfaces which are covered by these liga- 

 ments." This explanation, though undoubtedly correct in accounting for 

 the occurrence of splint, jarde, ringbone, and probably curb^ does not 

 furnish us with the cause of sore shins, navicular disease and bony tumours 

 (enlargements) due to blows ; for the inflammation in these cases does hot 

 necessarily originate at the points of insertion of the ligaments of joints. 



We may have the formation of pus on the outside or inside surface of the 

 periosteum (the membrane which covers a bone), or in the substance of the 

 bone. When the suppuration is on the outside of the periosteum, the 

 tissues which cover the periosteum will be swollen and the pus will be 

 watery and more or less tinged with blood. If it be beneath that mem- 

 brane, the pus may force the thickened and inflamed periosteum away from 

 the bone. If the pus invades the substance of the bone, it will be red in 

 colour and may give rise to death of the invaded portion of the bone by 

 reason of its interference with the local circulation. Whether the pus forms 

 on the inside surface of the periosteum or in the substance of the bone, the 

 bone, if it can be felt or seen, will be found to be swollen and the part 

 extremely painful on account of the resulting pressure on the nerves. In 

 all cases, the pus will corrode the tissues with which it is in contact, and 

 thus will tend to work its way to the surface by gravitation. Any dead 

 portion of bone will in time become separated from the living bone, and 

 will become more or less dissolved by the pus which surroimds it. If we 



