750 THE BONES AND JOINTS. 



largely as flocculi in the serum, or it may form false membranes over the 

 surfaces of the joint. 



Suppurative Arthritis may follow or be associated with the above forms 

 of inflammation. The synovial membrane is thickened and cloudy, and 

 there may be but a moderate amount of pus iu the joint, and a slight 

 degree of infiltration of the synovial membrane with pus cells. Under 

 these conditions resolution may occur. 



In other cases the accumulation of pus in the cavity may be great, 

 the synovial membrane and its surrounding tissue densely infiltrated 

 with pus cells. Under these conditions granulation tissue is apt to 

 form and the cartilages of the joints are apt to become involved. 

 There are swelling and proliferation or degeneration of the cartilage 

 cells; the basement substance becomes disintegrated, ulcerates, and 

 exposes the bone, in which osteitis, caries, rarefaction, etc. , may occur. 

 The new-formed granulation tissue may penetrate the cartilage, absorb- 

 ing the basement substance, and by metaplasia the cartilage tissue may be 

 converted into embryonal or granulation tissue. The pus may break 

 through the capsule of the joint and form large abscesses in the adjacent 

 soft parts. Sometimes the inflammation is not only suppurative but gan- 

 grenous, and runs a rapidly fatal course. The synovial membrane, artic- 

 ular cartilages, and ends of the bone all undergo a rapid suppuration 

 and gangrene. Acute arthritis may be incited by trauma, or it may 

 be associated with pyaemia, smallpox, measles, scarlet fever, pneumonia, ' 

 gonorrhosa, 2 diphtheria, mumps, typhus fever, glanders, the puerperal 

 condition, or other infectious diseases. In these cases the process is apt 

 to be suppurative, and is induced by various forms of bacteria. 



Chronic Arthritis may begin as such, or it may be the result of previous 

 acute inflammation. There is an increase of fluid in the joint. This 

 fluid is thin and serous, or is thickened with flocculi of fibrin and epi- 

 thelial and lymphoid cells, or is thick, syrupy, or even gelatinous. The 

 synovial membrane is at first congested, its tufts are prominent. Later it 

 becomes thickened, sclerosed, and anaemic ; the epithelium is destroyed, 

 and the tufts become large and projecting. From the distention of the 

 capsule there may be subluxations or luxuations of the joint, or the cap- 

 sule may be ruptured. 



Rheumatic Arthritis. An acute inflammation, usually exudative in 

 character and involving one joint after another, is characteristic of acute 

 articular rheumatism. The exudate is usually serous. 



A chronic form of so-called rheumatic arthritis is most common in 

 elderly persons, usually affecting several joints and advancing slowly and 

 steadily. There is a fibrous thickening of the synovial membrane and 

 the adjacent tissue. Fluid accumulations are not common. The artic- 

 ular cartilages are apt to degenerate or ossify, or become softened and 

 fibrillated, and they may disappear. The contracting synovial mem- 

 branes and fibrous tissue render the joints stiff and may cause consider - 



1 For bibliography of pneumococcic arthritis see Cave, Lancet, 1901, vol. i., p. 82. 



2 See bibliography, p. 194. 



