BREAKDOWN 133 



It will be gathered from what has been said that diagnosis is not 

 very difficult. 



The treatment is to apply a plaster bandage to the limb and sling 

 the animal for about six weeks. After removing the bandage allow an 

 interval of about a week to elapse before firing and blistering the 

 swollen part. 



THE METACARPO-PHALANGEAL OR GREAT SESAMOID 

 SHEATH 



This is found in the channel between the sesamoid bones. The 

 anterior face is formed by the posterior surfaces of the bones, which are 

 covered by smooth cartilage concave from side to side. Below this 

 the sheath is bounded anteriorly by the superficial vertical inferior 

 sesamoidean ligament and by the posterior surface of the glenoidal or 

 complementary cartilage of the pastern joint. The tube is completed 

 posteriorly by an expanded membranous sheet, which is attached to the 

 back of the perforatus tendon. This sheet is attached laterally by three 

 fibrous bands to the phalanges. 



An extensive synovial membrane covers the walls of the tube thus 

 formed, and is reflected on to the tendons of the superficial and deep 

 flexors. 



Superiorly this membrane extends upwards to the level of the 

 button of the small metacarpal bone, and the incision in flexor tenotomy 

 should thus be made above the level of the button. The superior 

 extremity of the membrane forms a bulging, in front of which is the 

 corresponding branch of the suspensory ligament, whilst behind it is the 

 perforans tendon, the branch of the suspensory separating this membrane 

 from the synovial membrane of the fetlock joint. 



Immediately below the sesamoid bone the synovial membrane 

 presents a small cul-de-sac which appears behind the branch of the 



