DISEASES OF BURS^E. 145 



DISEASES OF BTJKS^E. 



A bursa is strictly speaking a closed sac wholly lined with 

 synovial membrane. Some sub-tendinous so-called bursae have 

 direct communications with joint cavities, and are then in reality 

 extensions from the joint and are lined with a prolongation of 

 synovial membrane continuous with that of the joint itself. 



Enlargement of Bursse. Bursitis. A bursa may become 

 enlarged, usually by over-distension with bursal fluid, without 

 any obvious signs of inflammation, though probably inflammatory 

 influences are the ultimate cause of the increase in secretion. 

 There are certain bursse which from their anatomical position 

 are peculiarly liable to intermittent pressure or irritation, and 

 are consequently those which are most frequently enlarged. 



Pre-patellar bursa. The bursa which is found in the tissue 

 between the skin and the anterior aspect of the patella is more 

 commonly over-distended than any other in the body. This 

 bursa lies over the lower part of the patella and the upper part 

 of the ligamentum patellae, and is usually called the prepatellar 

 bursa. It is the largest bursal sac which normally exists. 

 Often its interior is divided by crossing bands of fibrous tissue 

 and it is not infrequently multilocular. 



Inflammation of this bursa with a large excess of bursal fluid 

 is very apt to occur from kneeling, and particularly in that form 

 of kneeling and leaning forwards with a certain amount of 

 movement of the parts knelt upon, as is occasioned in the 

 process of washing a floor. It is thus that the enlargement is 

 often seen in housemaids, carpet layers and others whose occupa- 

 tion entails such a position. Sometimes the walls of the bursa 

 become very much thickened, and the tumour formed may be 

 practically a solid one, but its position indicates its probable 

 origin. 



Excision of the bursal sac is the most satisfactory treatment. 

 This can be accomplished without difficulty or danger, though 

 perhaps warning should be given on two points. The first is 

 that the skin over the front of the knee is not infrequently much 



C.A.A. 10 



