SPRAIN OF THE FETLOCK-JOINT. 359 



entering about here into its composition, may be strained or torn 

 through; or its sheath may be the seat of injury, which is proba- 

 bly the case whenever the disease appears located about the 

 middle of the leg, between the knee and fetlock. Again, the 

 seat of lesion may be lower down the leg, at the places of im- 

 plantation of the bifurcations of the ligament into the sesamoid 

 bones, and the large bursae mucosae here placed, between the liga- 

 ment and the back of the fetlock joint, may become distended and 

 enlarged. But, in such a complex part as the fetlock joint and its 

 appurtenances, it is extremely difficult to say whereabouts the 

 precise seat of lesion is, and what parts in particular are suffering. 

 What, however, most of all tends to confuse us in seeking for the 

 seat and nature of disease in cases of '' sprain of the suspensory 

 ligaments" is the fact of such sprain but rarely occurring unat- 

 tended by lesion of other parts; in particular, of the flexor tendons 

 and fetlock-joint. And the consequent general tumefaction of leg, 

 arising so soon as it does in such cases after the accident, but too 

 often confounds all attempt at diagnosis. 



Sprain of the Fetlock- Joint. 



The joint of the fetlock, which is one of more than usual com- 

 plexity of structure, occupies that peculiar situation in the limb in 

 which weight does not operate perpendicularly upon it only, as it 

 does upon the knee, but presses in two directions, obliquely forward 

 as well as directly downward. That portion of the weight which 

 tends directly downwards is received by the sesamoid bones, and 

 these bones are sustained by the suspensory ligament ; we need, 

 therefore, feel no surprise that derangement of the ligament should 

 be a frequent concomitant of disorder of the joint. And not of 

 suspensory ligament onlyj but of flexor tendons, and on occasions 

 of extensor tendon as well ; for such is the structure of this joint, 

 that to these tendons and ligament is mainly owing its great 

 strength and unusual powers of flexibility and elasticity. Upon 

 the action of the sesamoid division of the fetlock-joint depends the 

 action of the suspensory ligament. If the sesamoid bones become 

 fixtures, the suspensory becomes useless ; or, supposing the sus- 



