134 THE SURGICAL ANATOMY OF THE HORSE 



suspensory ligament which is passing downwards and forwards to join 

 the extensor pedis tendon, whilst below this again is another dilatation 

 which makes its appearance below the fibrous band which passes from 

 the external aspect of the sufFraginis to the back of the perforatus 

 tendon. 



TENDINOUS WINDGALL 



When the synovial membrane of this sheath is abnormally distended 

 as a result of chronic synovitis, what are known as tendinous windgalls 

 make their appearance. 



Chronic synovitis is set up as a result of premature work, violent 

 exertion, or slipping when jumping, or it may be due to a weak con- 

 formation of the part transmitted from the sire and dam. 



There is an increased secretion of synovia, with the result that the 

 membrane becomes tightly distended. No distension can occur in the 

 posterior direction, on account of the powerful sheet which covers the 

 back of the perforatus tendon. Consequently we find that as the 

 condition progresses prominent rounded swellings make their appearance 

 in the position of the culs-de-sac which have been described, since these 

 are situations where there is least resistance to the outward bulging of 

 the membrane. 



At first the swellings are soft and compressible, and pressure on the 

 enlargement above the fetlock will cause a diminution in its size and 

 a corresponding increase in the size of the bulgings below the joint. 

 Later the walls of the gall become much thicker and the cavity 

 diminishes. In the latest stages the marked diminution in the 

 size of the cavity leads to increased tension on its walls. The 

 swelling is not now compressible, is more solid, and may even become 

 ossified. 



There is no difficulty in diagnosis, since the enlargement can usually 

 be seen. It is only in exceptional cases that lameness occurs, and in 



