LAMENESS: ITS CAUSES AND TREATMENT. 357 



tion of the shank bone (the tibia) and one of the bones of the hock 

 (the astragalus). The tendinous sac lies back of the articulation 

 itself and extends upward and downward in the groove of that joint 

 through which the flexor tendons slide. The dilatation of this articu- 

 lar synovial sac is what is denominated bog spavin, the term 

 thoroughpin being applied to the dilatation of the tendinous capsule. 



The bog spavin is a round, smooth, well-defined, fluctuating tumor 

 situated in front and a little inward of the hock. On pressure it 

 disappears at this point to reappear on the outside and just behind 

 the hock. If pressed to the front from the outside it will then appear 

 on the inside of the hock. On its outer surface it presents a vein 

 which is quite prominent, running from below upward, and it is to 

 the preternatural dilatation of this blood vessel that the term blood 

 spavin is applied. 



The thoroughpin is found at the back and on the top of the hock 

 in that part known as the " hollows," immediately behind the shank 

 bone. It is round and smooth, but not so regularly formed as the 

 bog spavin, and is most apparent when viewed from behind. The 

 swelling is usually on both sides and a little in front of the so-called 

 hamstring, but may be more noticeable on the inside or on the 

 outside. 



In their general characteristics bog spavins and thoroughpins are 

 similar to windgalls, and one description of the origin, symptoms, 

 pathological changes, and treatment will serve for all equally, except 

 that it is possible for a bog spavin to cause lameness, and thus to 

 involve a verdict of unsoundness in the patient, a circumstance which 

 will, of course, justify its classification by itself as a severer form of 

 a single type of disease. 



We have already referred to the subject of treatment and the 

 means employed — rest, of course — with liniments, blisters, etc., and 

 what we esteem as the most active and beneficial of any, early, deep, 

 and well-performed cauterization.* There are, besides, commenda- 

 tory reports of a form of treatment by the application of pressure 

 pads and peculiar bandages upon the hocks, and it is asserted that 

 the removal of the tumors has been effected by their use. Our 

 experience with this apparatus, however, has not been accompanied 

 with such ■ favorable results as would justify our indorsement of 

 the flattering representations which have sometimes appeared in its 

 behalf. 



OPEN JOINTS, BROKEN KNEES, SYNOVITIS, AND ARTHRITIS. 



The close relationship which exists among these several affections, 

 their apparently possible connection as successive developments of a 

 fiimilar, if not an essentially identical, origin, together with the 

 advantage gained by avoiding frequent repetitions in the details 



