DISEASES OF THE JOINTS 415 



Si/m2)toms and Diagnosis. — Acute synovitis of a joint leads 

 to heat of the parts, pain, distension of the capsule, and, 

 where the joint may be easily felt, fluctuation. In the 

 articulation with which we are dealing, however, these last 

 two symptoms are not easily detected, for the surrounding 

 structures — namely, the lateral and other ligaments of the 

 joint, the extensor pedis tendon in front, and the perforans 

 behind, together with the dense and comparatively un- 

 yielding nature of the skin of the parts — are such as to 

 prevent distension and fluctuation becoming marked to a 

 visible extent. We are able to diagnose the case as one of 

 foot lameness, and, with a history of a severe blow or other 

 injury, are able to assume that this condition, perhaps 

 attended with periostitis, is in existence. 



When other symptoms present themselves diagnosis may 

 be more certain. The animal becomes slightly fevered, 

 throbbing pains in the joint manifest themselves by irre- 

 gular pawing movements on the part of the patient. The 

 animal comes out from the stable stiff, even dead-lame, and 

 the limb is carried with the lower joints semiflexed. The 

 breathing is hurried and the pulse firm and frequent, while 

 in a bad case patchy perspiration breaks out at intervals on 

 various parts of the body. If with this we get a puffy and 

 tender swelling in the hollow of the heel, our diagnosis may 

 be certain at any rate as to the existence of joint trouble, 

 although, from reasons we have given, we may not be able 

 to mark its exact nature. 



2. Chronic. — Simple synovitis may in many instances 

 become chronic. In this case we have simply a pouring 

 into the synovial capsule of serous fluid, and with it an 

 increased quantity of synovia — this time with an absence 

 of the usual inflammatory phenomena. Beyond the swell- 

 ing of the capsule there is little to be noticed. The joint 

 becomes perhaps a little weaker, but pain or tenderness and 

 heat are entirely absent. Such a condition, by reason of 

 the natural rigidity of the parts, is not to be observed in 

 the foot, although at times it must most certainly occur. 

 Examples of such a condition are to be found in bog-spavin, 



