3880 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 swollen and tender and exhibit heat and pain. This swelling 
may not 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 showing 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 with 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. 
