236 THE EXTERIOR OF THE HORSE. 



When the articular dilatations of the knee are very old, their wall becomes 

 indurated and even ossified. This constitutes, in the latter case, one of the 

 varieties of hooped knee, of which we will speak farther on. 



The dilatations of the tendinous synovial bursce are of two varieties: they 

 appear either along the course of the flexor tendons or along that of the exten- 

 sors. Larger than the preceding, they may acquire very great dimensions. It 

 sometimes happens, at least with the second variety, that they communicate 

 between themselves or with the articular capsules, 1 an important peculiarity, 

 which should warn us against the danger of opening them. 



Hydropsy of the carpal sheath, better known under the name of carpal 

 or tendinous thorough-pin of the knee, is manifested by the formation of two tumors 

 posterior to the carpus, between the radius and the flexor muscles of the meta- 

 carpus. Each one of these is ovoid in shape ; the internal is ordinarily smaller 

 than the external, and both extend higher up than the articular dilatation. 

 Inferiorly, the tendinous dilatation is prolonged below the knee by a soft, 

 elongated, and irregularly- lobulated swelling, which follows the course of the 

 flexor tendons, and transmits its fluctuation and palpation to the two superior 

 culs-de-sac, thus giving evidence of its communication with them. This is a cir- 

 cumstance which is never noticed in the articular synovial dilatation. 



The synovial dilatations of the tendinous biirsse situated upon the anterior 

 capsular ligament of the carpus present analogous characteristics. They con- 

 sist of elongated tumors, from one to three in number, located under each of the 

 extensor tendons, and always perfectly distinct at the beginning of their forma- 

 tion. In advanced stages they become diffused over the anterior surface of the 

 knee, and may communicate among themselves and with the articular synovial 

 membranes; their parietes become indurated and, in some places, ossified. 

 They might be easily confounded with the cysts, which are always more super- 

 ficial, were it not for their relative situation with the tendinous cords. 



d. Osseous Apparatus. Xot even the osseous apparatus is exempt from 

 the traces of the wear and tear resulting from age or from excessive work. Ex- 

 ostoses appear, in time, upon the anterior surface of the carpal bones and upon 

 their articular edges, at the points which correspond to the insertions of the lig- 

 aments. These osseous tumors of the knee have received the generic name of 

 osselets. Their formation begins at the head of the rudimentary metacarpal, 

 preferably on the internal side, and then they gradually extend, little by little, 

 to the pieces of the two rows. When they are thus generalized, it has been the 

 custom to say that the knee is hooped, a very appropriate expression, which con- 

 veys to the mind the idea of the alterations of which the region is the seat 

 These osselets, like the tendinous and articular dilatations, are grave blemishes ; 

 they disfigure the animal, produce a deviation of the forearm and of the canon, 

 and, finally, often give rise to a rebellious and, very often, persistent lameness 

 of variable intensity. 



As the regions situated below the knee and the hock offer but few 

 differences in their anatomy and their external appearance, we will 

 study them with the posterior members. 



1 1 have examined a large number of articulations and have not once verified such a condi- 

 tion. (Harger.) 



