GENERAL DISEASES OE THE yoiNTS. 30? 



St;lar and binding ligaments), and synovial membrane, a thin 

 vascular structure which secretes the albuminous glairy fluid 

 known as joint-oil. 



INFLAMMATION. ARTHRITIS. SYNOVITIS. 



Here again the most common lesion is inflammation, from 

 which most of the others follow as consequences. This may 

 begin in the bones as a result of concussion, blows, etc., and 

 extend through the cartilage and ligaments to the synovial 

 membrane ; or it may originate in the ligaments as a conse- 

 quence of sprains or other injuries ; or in the synovial membrane 

 from wounds opening the joint and exposing it to the air; or it 

 may be a local manifestation of some constitutional disease 

 such as rheumatism, tubercle, glanders, farcy, etc., or finally it 

 may be due to plugging of the blood-vessels in consequence of 

 pus, ichor, or fibrinous clots washed on through the vessels 

 from some distant seat of disease. In all cases the whole of 

 the joint structures tend to be involved and the symptoms are 

 similar. 



The succession of clianges may be as follows : the inflamed 

 synovial membrane throws out a serous fluid filling the joint to 

 excess ; the ligaments and adjacent connective tissue also 

 throw out a semi-liquid exudation which forms a yielding 

 swelling around the joint, susceptible of indentation with the 

 fingers ; the cartilage covering the ends of the bones softens 

 and is changed into a fibrous material or is even absorbed, 

 leaving the bone bare; the bone exposed in this way may 

 ulcerate, if that has not previously commenced, or it may be 

 partially repaired by the deposit of a dense ivory-like layer 

 (eburnation), the smooth glistening surface of which glides 

 smoothly on that of the opposite bone ; lymph may be exuded 

 from the exposed surface of the bone and from the interior of 

 the synovial membrane, and this, as well as what is outside the 

 joint, may be developed into fibrous tissue restricting the move- 

 -nents of the joint, or more frequently into bone which binds 



