THECOCENTESIS 59 



are never directly connected with each other. Each one is 

 a distention of a separate synovial sac, having no communi- 

 cation with the other. 



Thoroughpin of the Knee or carpal thoroughpin, quite 

 frequently encountered in the hard-worked draft horse, is 

 to the carpal sheath what thoroughpin proper is to the tarsal 

 sheath. It is, however, much less common, and seems only 

 to occur where there is ample provocation in the form of ex- 

 ceptionally heavy work. A case is met here and there in the 

 high-stepping coach horse, but with this exception, horses 

 other than those subjected to heavy pulling are seldom ever 

 affected. This condition, which is very often accompanied 



Fig. 28 — Thoroughpin of the Knees. 



with an obstinate — if not incurable — lameness, is manifested 

 by the appearance of a fluctuating enlargement of the carpal 

 sheath just above the radio-carpal articulation. The dilated 

 cul-de-sac occupies- the space between the flexor muscles 

 and the posterior surface of the radius, bulging rather indis- 

 tinctly on both sides of the leg. Below the carpus a similar 

 but smaller distention is felt along the upper third of the 

 metacarpus. 



Other Synovial Distentions occur in the legs of horses, 

 but they are less serious from every standpoint than the ones 

 previously described. The synovials of the flexors, being 

 concerned in supporting weight and being submitted to the 

 great strain of locomotion, are more frequently affected with 



