122 PRACTICAL ANATOMY. 



surface articulates with the trapezoid; the internal sur- 

 face articulates with the unciform ; the palmar surface is 

 broad and flat; the dorsal surface is broad, flat, and 

 rough, for the attachment of ligaments. 



THE UNCIFORM. 



The unciform articulates above with the semilunar, 

 below with the fourth and fifth metacarpals, externally 

 with the os magnum, and internally with the cuneiform. 

 The posterior surface is rough ; the anterior surface pre- 

 sents the hook-like, unciform process ; it projects down- 

 ward from the junction of the palmar borders of the 

 external and inferior surfaces; the anterior annular 

 ligament is attached to it. 



These carpal bones, together with the five metacar- 

 pals, form the osseous palm. The carpus proper, con- 

 sisting of the two rows of bones, is convex from side to 

 side on the dorsal aspect and concave from side to side 

 on the palmar surface, where it presents prominences 

 along both the external and internal borders for the 

 attachment of the anterior annular ligament, which is 

 attached externally to the scaphoid and trapezium, in- 

 ternally to the unciform process and the pisiform bone. 



THE METACARPUS. 



The metacarpus is made up of five long bones, each 

 of which develop by two centres. The first metacarpal 

 articulates with the trapezium and the first phalanx of 

 the thumb ; it presents a base, shaft, and head. The 

 base is cuboidal and fits firmly against the trapezium ; 

 the shaft is prismoidal in form, convex on the dorsal 

 surface, concave on the palmar. The head is broad and 

 presents two condyles for articulation with the first pha- 

 lanx of the thumb. It is the shortest, thickest and 

 strongest metacarpal bone. 



