52 THE HORSE IxN MOTION. 



It is not necessary, in order to consider the relations and functions 

 of tliis organ, that we should enter into a detailed account of all the 

 ligaments of the foot; they are very numerous. Anatomists limit the 

 name to the strong band that has its upper attachment to the meta- 

 tarsus below the hock, and its lower one into the sesamoid bones, and 

 they have given the name of sesamoid ligament to that continuation 

 from those bones to the foot. We will not discuss with anatomists the 

 question of their identity, but, mechanically considered, they are one, 

 and, like the patella, the sesamoid bones may be said to be developed 

 in the ligament. If the name were limited to the first, it would be a 

 misnomer; for, to suspend the weight that is thrown upon it, it is 

 necessary that a counter force should act upon the opposite border of 

 the sesamoid bones equal in strength to that above it. If either part 

 were divided, the other would have no function, but united they con- 

 stitute an instrument that often bears the weight of the whole body. 

 It is a broad, thick band, resembling tendon, and may be felt above the 

 fetlock between the splint bones and the tendons of the perforatus 

 and perforans or " back tendons." This ligament fixes the sesamoid 

 bones in the position above and behind the articulation of the first and 

 second metatarsals, so that when the second metatarsal or pastern 

 bone is thrown out from under the first metatarsus they are drawn 

 into its place, and, their articular surfaces forming an arc of the same 

 circle, the loss of the pastern is not felt ; but the sesamoids now bear 

 the whole weight of the body, and they have no support but the sus- 

 pensory ligaments in which they are imbedded, and the tendons of the 

 perforans and perforatus, which cross the bridge between the sesa- 

 moids. The perfect equilibrium between the strength of the ligament 

 and the force it is required to resist is of the utmost importance. 

 When the horse is standing upon all four feet, the weight is equally 

 distributed, and the angles formed by the pasterns with the bones 

 above are small, for the weight upon each one is not great enough to 

 spring it far; but in running, the whole weight in every stride is 

 borne by each foot in turn for a short time, and the elasticity and 

 strength of its suspensory ligament must be, with that of its reinforc- 

 ing tendons, just equal to its requirements to support the body, for 



