OSTEOLOGY. 57 



scaphoid, semi-lunar, cuneiform, and pisiform; the second, or 

 distal row, in same order are trapezium, trapezoid, os magnum, 

 and unciform. 



SCAPHOID (boat-shaped), largest of first row, convex above, 

 concave below, articulates with five bones, as follows: superior 

 surface, with radius; inferior, with trapezium and trapezoid; 

 internal, with semi-lunar above and os magnum beneath. The 

 external surface has attachment of external lateral ligament of 

 wrist. 



SEMI-LUNAR (half-moon), crescentic in outline, presents 

 articulating surfaces for five bones, as follows : superior convex 

 surface with radius, inferior concave facet with os magnum and 

 unciform, quadrilateral internal facet with cuneiform, and ex- 

 ternal with scaphoid. 



CUNEIFORM is wedge-shaped, the base, directed outward, 

 articulates with the semi-lunar, apex with the interarticular fibro- 

 cartilage of wrist- joint, inferior surface with unciform, and 

 anterior with pisiform; in all, three bones. 



PISIFORM (pea-like) is a small, pea-shaped bone articulating 

 with anterior surface of cuneiform, and affording attachment to 

 annular ligament and two muscles, flexor carpi ulnaris, abductor 

 minimi digiti. 



TRAPEZIUM (a table), a very irregular bone, articulates 

 above by concave surface with scaphoid; below, by surface con- 

 cave from side to side, convex from before backward, with first 

 metacarpal, by internal surface with trapezoid, inferior with 

 second metacarpal. Its dorsal surface is rough; its palmar 

 grooved by flexor carpi radialis tendon. Muscular attachments 

 are three flexor ossis metacarpi, flexor brevis pollicis, and ab- 

 ductor pollicis. 



TRAPEZOID, smallest of second row, is wedge-shaped, apex 

 palmar; articulates with four bones superior surface with sca- 

 phoid, inferior with second metacarpal, external with trapezium, 

 internal with os magnum and interosseous ligament. 



It has one muscular attachment for flexor brevis pollicis. 



Os MAGNUM, or CAPITATE, the largest carpal bone, consists 

 of a body, neck, and head. The latter projects from the supe- 

 rior surface and articulates with the scaphoid and semi-lunar. 

 The inferior surface articulates with second, third, and fourth 

 metacarpal bones ; the external with trapezoid, and internal with 

 unciform ; in all seven bones. 



Muscular attachment for flexor brevis pollicis. 



UNCIFORM (hook-like), a wedge-shaped bone, so named 

 from the hook-like process, projecting from its anterior surface, 

 below its articulation with fourth and fifth metacarpals, and 



