380 DISEASES OF THE HORSE. 



under the body is subject to considerable pressure. If the leg is flexed 

 under the body so that the hoof or shoe is directly in contact with the 

 elbow, which may occur in horses having an extremely long cannon 

 bone or excessive length in the shoes, the greater part of the weight 

 of the chest is concentrated at this point and the pressure may cause a 

 bruise or an inflammation. 



Symptoms. — Under these conditions the point of the elbow may 

 become sw^ollen and tender and exhibit heat and pain. This swelling 

 may net only cover the point of the elbow, but sometimes reaches the 

 axilla and assumes such proportions that there is great difficulty in 

 using the leg, the animal show^ing signs of lameness even to the extent 

 of the circumflex step, as in shoulder lameness. This edematous con- 

 dition, however, does not remain stationary. It may by degrees' 

 subside or perhaps disappear. In the first instance it will become 

 more distinctly defined, with better marked boundaries, until it is 

 reduced to a soft, round, fluctuating tumor, with or without heat or 

 pain. There is then either a bloody or serous tumor or a purulent 

 collection, and following the puncture of its walls w^ith the knife 

 there will be an escape of blood, serum, or pus, as the case may 

 be, in variable quantities. In either case, but principally in that of 

 the cystic form, the tumor will be found to be subdivided by septa, 

 or bands running in various directions. 



Various changes will follow the opening of the tumor and the 

 escape of its contents. In a majority of cases the process of cica- 

 trization will take place, and the cavity fill up by granulation, the 

 discharge, at first abundant, gradually diminishing and the wound 

 closing, usually without leaving any mark. At times, however, and 

 especially if the disease has several times repeated its course, there 

 may remain a pendulous sac, partly obliterated, which a sufficient 

 amount of excitement or irritation may soon restore to its previous 

 dimensions and condition. 



In other cases an entirely different process takes place. The walls 

 of the cavity, cyst, or abscess become ulcerated and thickened, the 

 granulations of the sac become fibrous in their structure and fill up 

 the cavity, and it assumes the character of a hard tumor on the back 

 of the elbow, sometimes partly and sometimes entirely covered by the 

 skin. It is fibrous in its nature, painless to the touch, well defined 

 in its contour, and may vary in size from that of a small apple to 

 that of a child's head. 



This last form of capped elbow is the most serious of any, resisting 

 all known forms of mild treatment, and removable by the knife only. 

 The other forms, even that with the inflammatory aspect and its large 

 edematous swelling which interferes with the work of the animal, 

 may justify a much milder prognosis, and, aside from their liability 

 to recur, may be ranked with the comparatively harmless affections. 



