810 



HYGROMA OF THE KNEE IN CATTLE. 



or fibrosa, which sometimes affects the tendon sheath of the extensor 

 pedis, but more frequently the sheath of the extensor metacarpi 

 magnus. The swelling is sometimes chiefly formed by the sheath 

 of the tendon distended with serum (tendovaginitis chronica serosa), 

 sometimes by the greatly thickened connective tissue of the sheath 

 and its surroundings (tendovaginitis chronica fibrosa). This disease 

 of the tendon sheaths has often been found due to tuberculosis. 



A soft and hard form can be distinguished. The tendon sheaths 

 are often greatlv distended ; in one Gurlt found 17 lbs. of fluid. 



Fig. 469. — Knee tumour (cutaneous form), after StookHeth. 



Small papilla? form on the inner surface of the sheaths, and when 

 rubbed off appear like grains of rice ; this condition is termed 

 hygroma proliferum. Pus formation may also occur. 



The articular form presents a true tumour albus, that is, pro- 

 gressive increase and induration in the peri- and para- articular 

 connective tissue, and is always associated with exostosis formation 

 on the bones of the knee, fore-arm, and metacarpus. The swellings 

 are of variable hardness, and result from chronic inflammation of 

 the knee-joint. Ossification in the new connective tissue increases 

 the hardness of the swelling. 



