280 PARTICULAR LAMENESSES. 



fact, muscular appendages^ like the patdloe and naviculares, 

 by which leverage power is given to the muscles whose tendons 

 are inserted into or play over them. They are thus entirely 

 different from the small splint bones, which bear concussion, 

 being placed beneath other weight-bearing bones, and add to the 

 bulk of the lower part of the knee, without increasing its 

 weight to any great extent, which would be the case if the leg 

 were in one piece; and by being attached by inter-osseous 

 ligaments, not elastic ones, as Percivall maintains, deaden and 

 modify concussion much more effectually than if the union w^ere 

 entirely bony. 



2d. The suspensory ligament is not to any extent elastic, and 

 is for the purpose of keeping the sesamoids in their position 

 to prevent their descent in the same way as the inferior suspen- 

 sory Kgament prevents their ascent during the movements of 

 the tendons ; and also, by keeping the sesamoids firmly pressed 

 against the fetlock-joint, it forms a brace or stay, which pre- 

 vents over-extension of the fetlock and elevation of the toe, to 

 which there is always a tendency from the pressure of the 

 animal's weight. 



2>d. The sesamoids do not descend and ascend, as described 

 by Percivall, and even if the suspensory ligament were elastic, 

 this movement in the bones would be an impossibility, since 

 they are firmly attached to the tuberosities on the lateral aspects 

 of the upper part of the body of the os suffraginis by the in- 

 ternal and external lateral sesamoidean ligaments, and to each 

 other by the inter-osseous. In fact, they are pulleys, over 

 which the tendons play like ropes, enabling them the more 

 easily to lift the feet from the ground. 



How is it, then, that the fetlock pad comes nearly to the 

 ground at every stride of the race-horse ? It is because the 

 wdiole limb is pressed downwards upon the fetlocks, pastern, 

 and cotfin bones, which are placed obliquely under the animal's 

 body ; and this seeming descent of the sesamoids is simply an 

 increase of this obliquity. 



Dissections, and observations on the limb of the living animal, 

 have convinced me that extension at the fetlock-joint is very 

 limited, and that it is an impossibility to increase the obliquity 

 of the pastern, even by very gTeat pressure upon the fetlock- 

 joint, while the suspensory ligament is uncut, and that the in- 



