82 THE ANATOMY OF THE HORSE. 



The shank, or metacarpal region, consists of one large 

 and two small bones, which last are known by the name 

 of splents. The cannon is a plain cylindrical bone {Shel. 

 V and K), having its two extremities rather enlarged, the 

 superior of which articulates with the second row of the 

 knee {Skel. U) : posteriorly its head is indented into two 

 surfaces, receiving the two splents, one upon either side. Its 

 inferior surface is formed into two condyles {Skel.p) ; divided 

 by an eminence, with which it articulates with the great pas- 

 tern {Skel. Y) and the sessamoid bones {Skel. X), in a manner 

 that preserves the utmost freedom of flexion and extension ; 

 yet denies any lateral motion which would have detracted 

 from the necessary strength of the joint. The splents are 

 placed one on each side of the posterior part of the cannon ; 

 each having a superior articulating surface uniting it with 

 the carpal bones, and likewise a synovial articulation with 

 the upper extremity of the cannon. As they proceed 

 downwards they taper ; and are less closely bound by a fibro- 

 cartilaginous union (that is, by a union composed partly of 

 cartilage, partly of ligament) ; terminating at about two- 

 thirds the length of the cannon bone, by an unattached 

 button-like extremity. 



The purpose of this mixed union of fibro-cartilage, is to 

 allow of motion ; though, at the same time, to hmit it. It, 

 however, gives such play as renders the rider conscious of 

 elasticity in the animal's motions upon wdiich he is mounted. 

 Any extra weight, is very apt to put this connecting 

 substance to the stretch ; when it inflames ; becomes vas- 

 cular ; hot, and painful ; and is ultimately converted into 

 bone, which gives the name to the part ; the bony forma- 

 tion being called a splent, and the small bones being like- 

 wise so termed. The inner splent bone is more liable to 

 the disease than the outer ; and for two supposed reasons, — 

 firstly, as is said with much plausibility, because it is more 

 under the centre of gravity; and, secondly, because it 

 receives the entire weight of one of the lower row of the 

 bones of the knee ; and hence is more likely to be driven 

 downwards, or put upon the stretch. 



The large pastern hone {Skel. Y) is the first of an oblique 

 pile, which terminates the extremities of the horse. The 

 great pastern bone is cylindrical, and inclined obliquely for- 



