70 THE SURGICAL ANATOMY OF THE HORSE 



than in that on the scaphoid. Moreover, it not uncommonly happens 

 that the ridge on one cuneiform bone is much larger than the ridge on 

 the cuneiform magnum of the other hock in the same animal. This 

 materially affects the external contour of the joint, and frequently gives 

 rise to considerable discussion as to vi^hether the animal is or is not 

 affected with spavin. The hock with the larger ridge presents a much 

 coarser appearance. This point will be further referred to in dealing 

 with spavin. 



The Cuneiforvi Parvum. — This is the innermost of the bones of the 

 lower row, and is much the smallest bone in the tarsus. 



For the purpose of description it may be said to possess two surfaces, 

 two edges, a base, and an apex, although it is very irregular in shape. 



The superior edge presents a concave facet for articulation with the 

 scaphoid. The inferior edge shows two facets, the more anterior of 

 which is much the smaller and is flat. This facet is for articulation 

 with the large metatarsal bone. The other facet is concave, and is for 

 articulation with the inner small metatarsal. The base of the bone is 

 placed posteriorly. It is roughened and rounded. Inferiorly it is 

 drawn out into a nodular process. The apex projects forwards, and 

 carries a small facet for articulation with the cuneiform magnum. The 

 two surfaces are non-articular, the inner being convex and roughened, 

 whilst the outer is slightly concave. 



The Cuboid. — Of the tarsal bones this is the most regularly shaped. 

 It presents six surfaces. The superior surface is smooth and articular. 

 It is slightly convex, and articulates with the astragalus and calcis. The 

 inferior surface presents four articular facets in two pairs, one pair being 

 in front and the other behind. The inner facet of each pair articulates 

 with the large metatarsal bone, whilst the outer articulates with the 

 outer small metatarsal. 



The inner surface presents an antero-posterior groove, which, when 

 the tarsal bones are articulated with one another, completes with the 

 scaphoid and cuneiform magnum, a canal through which the perforating 



