OPERATIONS UPON FIBROUS TISSUES. 315 



collateral of the cannon, and the internal plantar nerve as its 

 satellite on the inside, and the external plantar nerve on the out- 

 side of the leg; while on the posterior leg the princijyal artery of 

 the cannon, which is the collateral metatarsal, is situated on the 

 outside of the bone, and comes in relation with the tendons only 

 in the lower part of the metatarsus. 



In the anterior legs, the carpal bursa, hned with its synovial 

 sac, extends downward on the flexor tendons as far as below the 

 superior third of the metacarpal region ; the synovial vaginal sac 

 of the sesamoid sheath runs upward along the tendons, as far as 

 the lower extremities of the small metacarpal bones. It is at about 

 the center of the middle third of the cannon that the operation 

 can be performed without fear of injuring either of these synovial 

 sacs. 



In the hind legs the tarsal sheath extends as far as the upper 

 part of the middle thii'd of the metatarsal region, and the sesamoid 

 sac being the same as in the anterior leg, a little larger space is 

 left for the operation. 



Modus Operandi. — To perform plantar tenotomy, the animal 

 must be thrown. Some practitioners operate with the horse on 

 his feet, but this position is dangerous, although by the use of 

 cocaine, much of the risk attending it may be obviated. The 

 animal is thrown on either side, according to the leg upon which 

 the operation is to be performed. If on the fore leg, it must be 

 on the side of the leg to be operated on in order to expose the 

 inside of the limb ; if on the hind leg, the animal should be thrown 

 in such a manner as to make the leg upon which the operation is 

 to take place the upper one. The arrangement, according to 

 Gourdon, makes the operation feasible both on the inside of the 

 fore, and the outside of the hind leg. 



Several modes of proceeding have been practiced. The old 

 method is by a large lateral incision, in which the tendon is ex- 

 posed, divided either with a bistoury, or by being raised from the 

 wound and then divided. But this style of procedure necessitates 

 the formation of large wounds, and is Hable to severe and trouble- 

 some complications, which the modern or subcutaneous method 

 ob^^ates. 



In performing the subcutaneous division, two instruments are 

 necessary. These are the straight and curved tenotomes. The 

 blade of the former is narrow, straight, thin and pointed ; that of 



