I20 THE SURGICAL ANATOMY OF THE HORSE 



a seton tape may be passed subcutaneously across the affected area, the 

 tape being smeared with a counter-irritant. 



THE CARPAL SHEATH 



This is the name usually given to the tube placed at the back of the 

 knee through which the tendons of the superficial and deep flexors of 

 the digit play. The tube is bounded anteriorly by the posterior aspect 

 of the posterior common ligament of the knee. Outwardly it is 

 bounded by the inner face of the pisiform bone, whilst posteriorly and 

 inwardly its formation is completed by the thick band of white fibrous 

 tissue which arches over the tendons and extends from the pisiform 

 bone to the edges of the scaphoid and trapezoid. Superiorly this band 

 is continuous with the fibrous aponeurosis of the forearm. The inner 

 aspect of the tube is lined by a synovial membrane which also surrounds 

 the flexor tendons. This membrane extends upwards above the knee 

 between the tendon of the extensor suffraginis and that of the flexor 

 metacarpi externus, and descends to the middle third of the metacarpal 

 region, where it will be found immediately in front of the edge of the 

 perforans tendon. These points should be carefully remembered. 



Traumatic Injuries to the synovial bursa lining the carpal 

 sheath are by no means uncommon. From what we have said in our 

 description of the membrane, little protection is afforded it above the 

 knee on the outer side of the limb in the area between the tendons of 

 the extensor suffraginis and flexor metacarpi externus muscles. Punc- 

 tured wounds received over this area from forks, projecting nails, &c., 

 thus very readily extend into the membrane and set up inflammation. 

 Below the knee the membrane is not infrequently accidentally opened 

 during the performance of tenotomy. 



The usual local symptoms of inflammation are presented. The part 

 is hot, and painful when palpated. The limb is held with the knee 



