BONES. 



Carpal Bones. From without inward the first (proximal) 

 row consists of the scaphoid, semilunar, cuneiform, and pisi- 

 form; and the second row of the trapezium, trapezoid, os 

 magnum, and unciform. Each bone is irregularly six-sided, 

 with non-articular palmar and dorsal surfaces. [203] 



Scaphoid. The inferior external angle of the palmar surface 

 projects (tuberosity). The superior surface is a convex facet 

 for the radius; the inferior surface is convex and consists of 

 two facets, for the trapezium externally, and the trapezoid 

 internally. The outer surface is narrow and non- articular; 

 the inner surface is hollow in front, for the os magnum, and 

 presents above this a narrow semilunar facet for the semilunar 

 bone. The dorsal surface is non-articular. [203] 



Semilunar. The palmar surface is larger than the dorsal. 

 The superior surface is convex, for the radius; the inferior is 

 deeply concave and consists of two facets, for the head of the 

 os magnum externally, and the unciform internally. The ex- 

 ternal surface is crescentic, for the scaphoid; the internal sur- 

 face is quadrilateral, for the cuneiform. [204] 



Cuneiform (pyramidal). The palmar surface has, infe- 

 riorly, a small oval facet for the pisiform; the dorsal surface is 

 ridged and grooved internally. The superior surface has a 

 convex facet for the triangular fibre-cartilage ; the in- 

 ferior surface is concavo-convex, for the unciform. The 

 external surface joins the semilunar; the inner is non-artic- 

 ular. [205] 



Pisiform. This is the shape and size of a large pea; dor- 

 sally it has an oval facet for the cuneiform; the rest of the 

 bone is rounded and non-articular. [205] 



Trapezium. The palmar surface has a prominent ridge, 

 with a groove beside it; the dorsal surface is irregular. The 

 superior surface is mainly rough but presents a half oval facet 

 for the scaphoid ; the inferior surface has an oval and saddle- 

 shaped facet for the first metacarpal. The external surface is 

 non-articular. The inner surface has two facets : the upper, a 



[147] 



