KNEE JOINT LAMENESS. 251 



therefore the bones more especially the seat of disease are the 

 scaphoid and lunar of the upper, and the trapezoid and os magnum 

 of the lower row ; also the head of the inner small metacarpal 

 bone, and that portion of the articular surface of the large metacar- 

 pal which corresponds to the os magnum, more particularly towards 

 its inner margin. I have often found that, while the bones situate 

 on the inner side could only be separated by fracture, those on the 

 outer have not been at all united by ossific matter. 



" It will also frequently occur, that the trapezoid and os magnum 

 are united by osseous deposit to the heads of the large and inner 

 small metacarpal bones, and this without any connexion with 

 splent. It is a common remark, that a splent is only of serious 

 consequence when it is situate close to the knee joint : in fact, this 

 form of carpitis has been confounded with splent ; and though the 

 disease will extend to the inner small metacarpal bone, it will be 

 found to affect only the head and its articular surface, and must 

 not be confounded with true splent. 



'' I think it probable that the existence of splent is the precursor 

 of that form of carpitis which affects only the trapezoid and head 

 of the inner small metacarpal. From this latter bone not being able 

 to perform its function, the bone immediately resting upon it re- 

 ceives a greater degree of compression than it is capable of endur- 

 ing, more especially during that period when the bones are still 

 soft from not having arrived at maturity, or in those animals 

 which have their bones naturally of a soft texture, such as is often 

 seen in under-bred horses : in old horses, the bones of which are 

 of a firm texture, and have been long the subjects of splent, Na- 

 ture provides for this alteration by the diminution of that part 

 of the body of the trapezoid which rests upon the head of the 

 small metacarpal, or of the head of that bone itself, by which 

 means much of the concussion which would otherwise occur is 

 got rid of. 



" It is but rare to find that the disease extends to the joint 

 formed by the os brachii and upper row of the carpus. 



" There is but one other observation I have to make, that is, to 

 the disease of the joint dependent upon external injury. This is 

 most frequently the result of broken knees, either from the severity 

 of the injury, or from putting the animal too soon to work after 



