THOEACIC LIMBS 607 



directed dorsally and to the ulnar side. It is divided into two articular 

 facets by a pit in which is inserted a ligament from the trapezoid. 



The upper facet, which is long and narrow, is bounded above by 



the proximal surface, in front by the dorsal surface, behind by the 







FIG. 469. 

 Proximal Side. 



With Trapezoid. 

 Dorsal Side. Pf Palmar Side. 



With Second Metacarpal. 



Distal Side. 



LEFT TRAPEZIUM, ULNAR SURFACE. 



palmar surface, and below by a part of the lower border of the radial 

 surface. It articulates with a facet of corresponding shape on the 

 radio-palmar surface of the trapezoid. 



The lower facet is nearly square, and does not occupy the same 

 plane with the upper facet, but faces rather in a dorso-palmar direction. 



FIG. 470. 



Dorsal Side. 



With First Metacarpal. ~^\ \ jjj , With Second Metacarpal. 



Radial Side. iiim Ulnar Side. 



With Trapezoid. 



Palmar Side. 



LEFT TRAPEZIUM, DISTAL ASPECT. 



It articulates with the radial side of the head of the second meta- 

 carpal. 



Nomenclature. Trapezium means an irregular four-sided figure, 

 and is derived from the Greek trapeze, a table. Os multangulum 

 magnus (the larger many-angled bone) is in general use among 

 European anatomists. The Germans translate these terms into Trapez- 

 bein and das grosse vieleckige Bein. In the French we find le trapeze. 

 The trapezium is carpale I. in comparative anatomy. 



Determination. If the proximal surface be held upward and the 

 dorsal surface toward the student, the radial side will point to the side 

 to which the bone belongs. 



Articulation. The trapezium articulates with the scapho-lunar 



