338 DISEASES OF THE ARTICULATIONS 



The cartilage of the end of the joints is rarely affected by the various 

 inflammatory conditions. In acute cases of suppuration of the joints, 

 the cartilage may he softened, perforated, or partially destroyed, so 

 that the bone is bare in some places. In many chronic cases of inflam- 

 mation of the joints the cartilage becomes macerated and dissolved into 

 fibres, or it may be overgrown with abnormal synovial extensions. As 

 soon as the bone proper becomes involved in the inflammatory process, 

 extensive granulations form, causing a peculiar spongy growth on the 

 cartilage. These granulations crowd and perforate the bone here and 

 there and also affect a cartilage of the opposing bone, leading to a cic- 

 atricial growth on the end of the joint. In some cases we also see the 

 fibres and cells of the cartilage becoming soft and finally growing up with 

 numerous raised cartilaginous cells, and presenting an acute inflammation 

 of the ends of the joints. From these periodical conditions we may find 

 a marked alteration in the form of the joint in which the edges of the 

 joint protrude, and the inner surface is hollowed and grooved. A 

 peculiarity of deforming inflammation of the joints is an inflammation of 

 the synovial membrane, with abnormal excretion of synovia and a great 

 enlargement of the free or loose portion of the membrane which may 

 develop into papilla-shaped masses. 



The bone, as a rule, does not become affected in acute inflammation 

 of the joint; but if it should become uncovered from suppuration of the 

 cartilage, the inflammation extends to the spongiosa, and we see occasion- 

 ally the formation of purulent or granular centres on the surface of the 

 bone. In rare cases the periosteum becomes covered with osteophytes. 



Acute Synovial Inflammation of the Joints. 



{Synovitis Acuta Serosa.) 



The joint is swollen and hot, and the animal shows pain on pressure 

 or movement of it. These symptoms indicate an inflammation of the 

 synovial membrane and a lessening of the secretion of synovial fluid 

 in the joint. It is very rare that we see intense fibrinous excretions 

 (synovitis sero-fibrinosa) , and still more rare are those cases of colorless 

 blood-cells mixed with detached epithclia. The animals are lame when the 

 joint is moved, especially at the beginning and toward the end of any 

 movement of the joint. Very frequently small dogs will only walk on 

 three feet, carrying the inflamed member. 



The following causes may produce synovitis: Crushing or con- 

 cussion of the joint, ])lows, sprains (such as falling from a height). In 

 cases of injuries of the joints, we may expect only a simple synovitis 

 when the injuring object is clean and the wound is cleansed immediately 

 after the injury (removing the blood-clots and applying antiseptic 



