THORACIC LIMBS 599 



irregularly triangular, the widest part being at the dorsal border. It 

 is divided into two parts by a groove passing obliquely from the ulnar 

 side of the dorsal border to the radio-palmar angle. The radial part 

 is slightly concave, and faces downward and to the ulnar side of the 

 hand, while the ulnar part is strongly convex from side to side, and 

 faces to the radial side. On the ulnar side of this facet is a ridge 

 which passes obliquely to the radial and palmar sides, parallel to the 

 groove just described, and divides the whole under surface into two 

 parts. On the ulnar side of this ridge is the narrow, deeply concave 

 surface for the vertical plate of the magnum. This groove is wider 

 behind than in front, faces downward and inward, and is directed 

 obliquely across the bone, but leaves a small pit near the palmar 

 border, between it and the ridge on the radial side. The pit furnishes 

 a point of insertion for a ligament. Next to this facet, and separated 

 from it by a slightly elevated line, is the curved surface for the unci- 

 form. This is crescentic in outline, the emarginate side toward the 

 radial side of the bone. It is concave in a dorso-palmar direction, 

 faces distally and radially, and receives the narrow proximal end of 

 the unciform. 



The ulnar surface is flat and attached by ligament to the radial side 

 of the cuneiform. Its arcuate upper margin passes into the rounded 

 proximal surface of the bone, and its emarginate distal margin is 

 sharply defined by the edge of the facet of the unciform. 



The palmar surface (Fig. 459) is almost rectangular, and about 

 twice as wide as high. Its ulno-distal angle is cut off squarely, and 



FIG. 459. 

 Proximal Side. 



With Ctiineifnrm With Radius. 



m - \ i Groove for Tendon of 



'FLEXOR CARPI RADIALIS. 



Ulnar Side. &SWV 51 Radial Side. 



With Unciform. With Magnum. 



Distal Side. 



LEFT SCAPHO-LTJNAR, PALMAR SURFACE. 



the radio-distal angle is produced into the process of the bone. The 

 surface is nearly flat, and is rough for the attachment of ligaments. Its 

 ul liar and distal borders are sharply defined, but the ulnar part of its 



