Bones of the Upper Extremity. 107 



The first carpal row (see also Fig. 240), considered as a whole, has proximalward 

 an elongated oval, markedly convex, articular surface, in the formation of which participate 

 the os naviculare and the os lunatum especially, the os triquetrum to a less extent; the os 

 naviculare and the radial part of the os lunatum articulate with the facies articularis carpea 

 radii, the ulnar part of the os lunatum and the os triquetrum with the discus articularis 

 situated helow the capitulum ulnae. The os pisiforme takes no part in the articulation with 

 the hones of the forearm nor in that with the second carpal row r , hut is simply attached, 

 volarward, to the os triquetrum. Distalward the first carpal row is bounded by a surface, 

 the radial portion of which (formed by the os naviculare) is convex and projects markedly 

 distalward, and its. ulnar portion (formed by the ossa naviculare, lunatum, triquetrum) re- 

 presents a markedly hollowed out depression. 



The second carpal row (see also Fig. 240) ends proximalward in a surface, the 

 radial portion of which (formed by the ossa multangula majus et minus), is concave and its 

 ulnar part (formed by the os capitatum and os hamatum) represents a head projecting markedly 

 proximalward. These proximal surfaces are impressions of the corresponding distal surfaces of 

 the first carpal row. The distal boundary of the second row is formed by a wavy surface in 

 . which the ossa metacarpalia are deposited ; furthest radial ward lies the saddle-shaped surface 

 for the os metacarpale I (formed by the os multangulum majus) ; after this comes the surface 

 for the os metacarpale II (formed by the ossa multangula majus et minus, os capitatum); 

 then the surface for the os metacarpale III (formed by the os capitatum), then the surface 

 for the os metacarpale IV (formed by the os capitatum and the os hamatum) and finally, the 

 surface for the os metacarpale V (fonned by the os hamatum). 



The carpus (wrist) (see Figs. 148 and 149) is on the whole almost quadrangular, 

 and narrower proximally than distally. It is besides curved so as to be somewhat convex 

 dorsalward and, accordingly, volarward forms a groove which is made deeper by the fact that 

 the radial and the ulnar sides are somewhat elevated; radial ward are the tuberculum ossis 

 navicularis and the tuberculum ossis multanguli majoris which together form the eminentia 

 carpi radialis ; ulnarward the os pisiforme and the hamulus ossis hamati project upward and 

 form the eminentia carpi ulnaris. The groove bounded by the two eminentiae carpi is called 

 the sulcus carpi; it is converted into a complete canalis carpi by the ligamentum carpi 

 transversum which extends between the eminentiae; through this canal go the tendons, vessels 

 and nerves to and from the fingers. 



