142 THE SURGICAL ANATOMY OF THE HORSE 



injury lameness is usually severe. There is heat in the part, which swells 

 and presents the usual symptoms of acute inflammation. 



Regarding the treatment, should there be a cutaneous wound, this 

 should be dressed with antiseptics, and cold applications utilised to 

 reduce the swelling. The tendon can usually be replaced without 

 much difficulty, but great difficulty is experienced in keeping it in 

 position until the ruptured slip has reunited. As a rule the result is 

 unsatisfactory, and rarely can the animal be afterwards utilised for fast or 

 heavy work. Macqueen replaces the tendon and fixes it in position by 

 means of sutures with satisfactorv results. 



THE TARSAL SHEATH— TENDINOUS THOROUGHPIN 



The tarsal sheath is the name given to a tube which is placed at the 

 back of the hock. It is bounded anteriorly in its superior portion by 

 the posterior face of the posterior common ligament of the tibio- 

 astragaloid articulation, and below this by the back of the tarso- 

 metatarsal ligament. Outwardly it is bounded by the grooved inner face 

 of the tuber calcis, whilst posteriorly and inwardly its boundaries are 

 completed by a fibrous arch which stretches across from the back of the 

 calcis to blend with the internal lateral ligament. 



There is thus formed a complete tube which is open above and 

 below, and through the tube the tendon of the flexor perforans muscle, 

 together with a number of vessels and nerves, passes. The tube is lined 

 by an extensive synovial membrane, which covers the posterior surface of 

 the ligaments to which we have referred above, and which also envelops the 

 tendon playing through the tube. The membrane extends in the upward 

 direction above the limit of the tube for a distance of from two to three 

 inches, a little in front of the tendo- Achilles, whilst inferiorly it presents 

 a cul-de-sac which extends to the middle third of the metatarsal region. 



This svnovial membrane is of great importance. Its function is to 



