THOEACIC LIMBS 617 



in a radio-proximal direction. It is divided into two parts by the 

 transverse depression seen at the junction of the middle and posterior 

 thirds. The anterior or dorsal part is convex from before backward, 

 and also slightly convex from side to side. The smaller palmar por- 

 tion is slightly concave in both directions, and faces to the dorsal 

 and radial sides as well as in a proximal direction. Both parts are 

 covered with cartilage and articulate with a facet on the uluar side 

 of the distal surface of the scapho-lunar. 



Nomenclature. Unciform is from uncus, a hook, and forma, 

 likeness, because of the shape of the human bone. The Latin name 

 adopted by European anatomists is os hamatum, from hamatus, hooked. 



FIG. 483. 

 Palmar Side. 



. With Scapho-lunar. 



Radial Side. Ulnar Side. 



Dorsal Side. 



LEFT UNCIFORM, PROXIMAL SURFACE. 



It is das Hakenbein of the Germans and I'os crochu of the French. 

 The unciform is formed by the union of the carpalia IV. and V. of 

 comparative anatomists. 



Determination. If the proximal side be held upward and the 

 dorsal side toward the student, the palmar end of the proximal surface 

 will point to the side to which the bone belongs. 



Articulation. The unciform articulates above with the scapho- 

 lunar, on the ulnar side with the cuneiform, on the radial side with 

 the magnum, and below with the fourth and fifth metacarpals. 



Ossification. The unciform has but one centre of ossification. 



THE METACARPUS. 



General Description. The Metacarpus forms the middle region 

 of the hand, and therefore lies between the carpus, or wrist, above, and 

 the phalanges, or fingers, below. (Fig. 484.) 



It comprises five long bones, the metacarpal bones of the thumb, 

 the index, the middle, the ring, and the little finger, which are 

 numbered the first, the second, the third, the fourth, and the fifth 



