PATHOLOGY 



249 



In some forms the amount of synovial fluid is increased, occasionally 

 turbid but — and this is characteristic of chronic arthritis— nciie;- purulent. 

 The villi of the synovial membrane are hyperemic (violet red), showing 



Fig. 5. — Metatabso-Phalangeal Articulation of a Chorus Girl, Aged Forty-Five, with 

 Beginning Chronic Arthritis "without Symptoms; Death from Contracted Kidney. 

 Fibrillation of the cartilaginous basic substance, proliferation of the cartilage ceils, the 

 capsules of which partially open into the joint cavity. Tlie capsule of the joint is intact. 



marked proliferation; occasionally fatty degeneration is noted (lipoma arl)o- 

 rescens), and in well developed cases present the appearance of sheep's wool; 

 the capsule and its surroundings show edematous infiltration. The bone 

 appears unchanged in the early stages of the disease. 



In later stages the smooth surfaces are denuded of cartilage, the bone is 

 bare, and, if joint movements have still been performed, shows grooves, re- 

 scmliling the crevasses of a glacier. Often the bared surface is dense and 

 ivory-like, or it is covered by connective tissue which extends from the borders 

 of the synovial membrane, from transformed cartilage cells, or even from 

 the surfaces bare of cartilage. This connective tissue covers the joint surface 

 (Kachel), and frequently adheres to the opposing joint ends (fibrous anky- 

 losis). These connective tissue striae may calcify and finally ossify (bony 

 ankylosis). Upon the border of the cartilage, wherever it is covered by 

 synovial moml}rane, ecchondroses develop which are transformed into osteoids 

 and finally into bony tissue. By these exostotic marginal proliferations, the 

 joint end attains a mushroom form and resembles the crown of the antler 

 of a deer. 



