DISTENSION OF SYNOVIAL CAVITIES IN THE FORE LIMB. 



815 



a number, and has satisfied himself of their true character by post- 

 mortem examination. 



(B) Distension of the sheaths of flexor tendons. 



It is now generally allowed that distension of the sheaths of 

 flexors calls for greater care in treatment than that of extensors. 

 The first variety may be divided as follows: — ■ 



1. Knee gall. In the carpal arch at the back of the knee, the 

 flexor tendons have a large sheath which 



begins about 2 inches above the carpus 

 and extends to near the middle of the 

 metacarpus (Fig. 471, c). Eichbaum 

 says that above and below the joint its 

 lateral walls are unprovided with fibrous 

 strengthening coats, and thus explains 

 why the swelling appears above and 

 below the knee, and frequently on the 

 inner, sometimes on the outer side. The 

 enlargement may become excessive, but 

 generally takes the form of a longish, 

 soft swelling, the outline of which 

 corresponds with the borders of the 

 sheath. When the limb is lifted, the 

 communication between the upper and 

 lower portions of the swelling is easily 

 detected by palpation. 



2. Tendinous wind galls. The 

 above-described tendon sheath only 

 extends as far as the middle third of 

 the metacarpus, the next portion of 



the flexor tendons being surrounded by loose connective tissue. At 

 the lower third the great sesamoid sheath begins and extends down- 

 wards behind the fetlock-joint to the centre of the coronet bone 

 (Fig. 471, d), where it is separated from the navicular sheath by an 

 attachment of the perforans tendon. It lines the fetlock aponeurosis 

 and sesamoid pulley and is reflected on the flexor tendons. Below 

 the fetlock a fibrous expansion surrounds it so firmly that distension 

 usually only occurs above the fetlock-joint, and (on account of 

 the position of the flexor tendons) on either side. At this point 

 the sheath is covered with loose connective tissue, which favours 

 the production of the two characteristic longish swellings lying 

 on either side of the lower end of the metacarpus, close to the 

 flexor tendons and extending upwards on the cannon bone. Their 



Fig. 470. — Distension of the extensor 



pedis and flexor sheaths. After a 



photograph. 



