CHAPTER XII 
DISEASES OF THE JOINTS* 
A. SYNOVITIS. 
Definition — By the term ‘ synovitis’ is indicated an inflam- 
mation of the synovial membrane. It may be either 
(a) Simple or Acute, or it may be (b) Purulent or Suppu- 
rative. 
In the simple form there is little or no tendency for the 
affection to implicate the other structures of the joint, 
whereas in the suppurative form the joint capsule, the liga- 
ments, and the bones soon come to participate in the 
diseased processes, giving us a condition which we shall 
afterwards describe as acute arthritis. 
(a) Surete Synoviris. 
1. Acute—(Causes).—Simple or acute synovitis is nearly 
always brought about by injury to the joint—by blows 
or bruises, or by sprains of the ligaments. At other times 
it occurs without ascertainable cause, and is then put down 
to the influence of cold, or to poisonous materials (as, for 
* Properly speaking, we have in the foot of the horse but one joint 
—namely, the corono-pedal articulation. 
Although not a joint in the strict sense of the word, we, nevertheless, 
intend here to consider the navicular bursa as such. In this apparatus, 
although we have no articular cartilage proper, and no apposition of 
bone to bone, we still have a large synovial cavity, and in close proximity 
to it bone. We may, in fact, and do get in it exactly similar changes 
to those termed ‘synovitis’ and ‘arthritis’ elsewhere. Therefore, we 
include the changes occurring in it in this chapter, and hence the plural 
use of the word to which this note refers. 
413 
