ARTICULATIONS. 



large. The base has a saddle-shaped facet for the trapezium 

 but no lateral facets ; externally it has a slight tubercle. The 

 second is the longest. The base has a deep facet for the trape- 

 zoid; on its radial side a half oval facet for the trapezium; 

 and on its ulnar side a narrow facet for the os magnum, and 

 in front of this two half-oval facets for the third metacarpal. 

 The third has a pointed process (styloid), at the back of the 

 base, which is directed radialward. The base has a facet 

 superiorly for the os magnum, with two half-oval facets on the 

 radial side for the second metacarpal, and two facets, oval or 

 circular, on the ulnar side for the fourth metacarpal. The 

 fourth has a quadrilateral facet at its base for the unciform, 

 with two facets on the radial side for the third metacarpal, 

 and a narrow facet on the ulnar side for the fifth. The fifth 

 has a saddle-shaped base, for the unciform, with a tubercle 

 on the ulnar side ; on its radial side is a facet for the fourth 

 metacarpal. [210] 



Phalanges. There are three for each finger and two for the 

 thumb. The first (proximal) on each finger is the longest and 

 stoutest, and curves slightly forward; the palmar surface is 

 flat, with sharp lateral borders; the dorsal surface is convex 

 transversely. The proximal end is enlarged and has an oval 

 facet for the metacarpal ; the distal end is smaller and its facet 

 is convex and divided into two condyles by a groove. The 

 second resembles the first, except that it is smaller and its prox- 

 imal facet is divided by an antero-posterior ridge. The third 

 (terminal, or ungual) is the smallest and has a spatula-shaped 

 surface on its distal end, for the nail; its proximal facets re- 

 semble those of the second. [212] 



ARTICULATIONS. 



Sterno-clavicular Joint. This arthrodial diarthrosis in- 

 volves the sternal end of the clavicle, and the manubrium and 

 (slightly) superior surface of the first costal cartilage, close 

 to the sternum. A nearly circular interarticular fibro-cartilage, 



[149] 



