380 



THE ANATOMY OF THE HORSE 



in front. Descending from the bocl}^ is the thin wedge of bone which is 

 united iudissolubl}^ with the shaft of the radius at the point marked 5, 

 and may be traced down to the carpal joint. 



The articular surface comprises part of the elbow joint, and has below it 

 some roughened inequalities for the attachment of ligaments. 



The olecranon process, or elbow, is of considerable size and strength, form- 

 ing a strong lever for the action of the triceps muscle, which is inserted in 

 its point. Its anterior edge has a sharp point, which deepens the articular 

 cavity, and checks the motion of the joint from being carried too far. 



THE CARPUS (KNEE) AND METACARPUS 

 (CANNON) 



The knee of the horse corresponds with the wrist of man, and though the 

 name so well known to horsemen will probably always be maintained, yet 

 scientifically each of the bones receives the corre- 

 sponding names, and the whole group is called the 

 carpus. 



The anterior surface of the carpus is convex ; the 

 posterioi', concave and irregular, and marked by bony 

 prominences. 



It consists of eight bones, disposed in two rows, 

 one above the other, as follows : — 



The first, or top row, beginning to enumerate 

 from within outwards, consists of the scaphoid, lunar, 

 cuneiforme, and pisiforme bones. 



The second, or lower row, consists of the essa tra- 

 pezoid, magnum, and unciforme, and sometimes of a 

 small floating bone situated behind the trapezoid. 



The superior row may be described as follows : — 



Os ScAPHOiDES (o-Kci^r;, a cradle), the largest of 

 this row, articulates superiorly with the infeiior and 

 inner extremity of the radius, internally by means of 

 two distinct facettes with the os lunare, and inferi- 

 orly Avith the os trapezoides and os magnum. 



Os Lunare (luna, the moon) articulates superi- 

 orly with the radius, internally as before mentioned 

 with the OS scaphoides, and externally through the 

 medium of two facettes with the os cuneiforme. 



Os Cuneiforme (cuneus, a wedge) articulates supe- 

 riorly with fehe inferior and outer extremity of the 

 radius, inferiorly with the os unciforme, and pos- 

 teriori}'^ with the OS pisiforme. 



Os Pisiforme (pisum, a pea) is situated at the 



postero-external side of the top row, and presents 



for description two surfaces and four borders. The 



external surface is unevenly convex, and elevated 



for ligamentous attachment. The internal surface is concave and porous, 



and also roughened for ligamentous attachment. The anterior border 



rio. 27. — FoiiE View oi- 

 TUE Carpal Bones, cosi- 



MONLY CALLED THE KnEE. 



•2. Lower extremity i,f 

 radius. 



3. Ulna, lower extruniil\' 



of. 



4. Os pisiforme. 



5. — cuneiforme. 



6. — lunare. 



7. — scaphoides. 



8. — unciforme. 



9. — magnum. 



10. Large metacariial bone. 



11. Small metafarjuil bone. 



