Bones of the Upper Extremity. 



105 



Os lunatum 



Os pisiforme 



Os triquetrum 



Os naviculare manus 



Os hamatum 



Os capitatum 



Os multangulum minus 

 Hamulus ossis haniati 



Os multangulum majus 



138145. Bones of the right carpus, ossa carpi, 



shown singly, from the^ surface. 



The OS multangulum majus or large multangular bone (0. T. trapezium) has 

 proximally a slightly concave articular surface (for the os naviculare), distalward a saddle- 

 shaped surface (for the os metacarpale I), ulnarward a somewhat larger, concave surface (for 

 the os multangulum minus) and a small surface (for the os metacarpale II). On the volar 

 surface is a small projection, tuberculum ossis multangull majoris, and ulnarward from it a 

 groove (for the tendon of the m. flexor carpi radialis). 



The os multangulum minus or small multangular bone (0. T. trapezoid bone) 

 presents proximally a slightly concave articular surface (for the os naviculare) distalward a 

 flat saddle-shaped surface (for the os metacarpale II); on the radial surface lies a slightly 

 convex articular surface (for the os multangulum majus), on the ulnar a feebly concave surface 

 (for the os capitatum). 



The os capitatum (0. T. os magnum) is inserted in its proximal part into the deep 

 concavity formed by the os naviculare and the os lunatum. It supports there a markedly 

 convex articular surface (for the os lunatum), distalward a tripartite, flat, articular surface (for 

 the ossa metacarpalia II, III, IV); radialward are convex articular surfaces for the os navi- 

 culare and the os multangulum minus, ulnarward a flat articular surface for the os hamatum. 



The os hamatum or hook bone (0. T. unciform bone) presents a large, articular sur- 

 face, curved like the thread of a screw (for the os lunatum and the os triquetrum) directed 

 proximally and at the same time ulnarward ; distally is a double articular surface (for the ossa 

 metacarpalia IV, V) and radialward a single, flat, articular surface (for the os capitatnm). On 

 the volar surface a flat somewhat curved process projects upward, the hamulus ossis hamati 

 (0. T. uncifonn process). 



