80 SCAPHOID BfcNE SEMILUNARE CUNEIFORME. 



hand; if it be directed to the right, the bone belongs to the right; 

 and if to the left, to the left carpus. 



Articulations. With five bones; by its convex surface with the 

 radius ; by its concave surface, with the os magnum and semilunare ; 

 and by the extremity of its upper or dorsal border, with the trapezium 

 and trapezoides. 



Attachments. By its tuberosity to the abductor pollicis, and 

 annular ligament. 



The semilunar bone may be known by having a crescentic con- 

 cavity, and a somewhat crescentic outline. It presents for ex^ami- 

 nation four articular surfaces and two extremities; the articular 

 surfaces are, one concave, one convex, and two lateral one lateral 

 surface being crescentic ; the other nearly circular, and divided 

 generally into two facets : and the extremities, one dorsal, which is 

 quadrilateral, flat, and indented, for the attachment of ligaments ; 

 the other palmar, which is convex, rounded, and of larger size. 



To determine to which hand it belongs, let the bone be held per- 

 pendicularly, so that the dorsal or flat extremity look upwards, and 

 the convex side backwards (towards the holder). The circular 

 lateral surface will point to the side corresponding with the hand to 

 which the bone belongs. 



Articulations. With five bones, but occasionally with only four ; 

 by its convex surface, with the radius; by its concave surface, 

 with the os magnum ; by its crescentic lateral facet, with the sca- 

 phoid ; and by the circular surface, with the cuneiform bone and 

 with the point of the unciform. This surface is divided into two 

 parts by a ridge, when it articulates with the unciform as well as 

 with the cuneiform bone. 



The cuneiform bone, although somewhat wedge-shaped in form, 

 may be best distinguished by a circular and isolated facet, which 

 articulates with the pisiform bone. It presents for examination 

 three surfaces, a base, and an apex. One surface is very rough 

 and irregular; the opposite forms a concave articular surface, 

 while the third is partly rough and partly smooth, and presents 

 that circular facet which is characteristic of the bone. The base 

 is an articular surface, and the apex is rough and pointed. 



To distinguish its appropriate hand, let the base be directed 

 backwards and the pisiform facet upwards ; the concave articular 

 surface will point to the hand to which it belongs. 



Articulations. With three bones, and with the triangular fibro- 

 cartilage. By the base, with the semilunare; by the concave sur- 

 face, with the unciforme ; by the circular facet, with the pisiforme ; 

 and by the superior angle of the rough surface, with the fibro- 

 cartilage. 



The pisiform bone may be recognised by its small size, and by 

 possessing a single articular facet. If it be examined carefully, it 

 will be observed to present four sides and two extremities; one 

 side is articular, the smooth facet approaching nearer to the 

 superior than the inferior extremity. The side opposite to this is 



