THE tJPPER EXTREMITIES. 181 



row are the scaphoid and semilunar bones, on the outer 

 side, articulating with the radius, the cuneiform artic- 

 ulating with the fibro-cartilage of the wrist-joint, and 

 the pisiform. In the second row, in corresponding posi- 

 tions, are the trapezium, trapezoid, os magnum, and 

 unciform. The eminence felt on the radial side of the 

 wrist is the protuberance of the scaphoid, while the 

 pisiform is generally felt on the ulnar side. 



FIG. 73. Right carpal bones, dorsal surface. T, trapezium; T', trapezoid; 

 7, os magnum; U, unciform; S, scaphoid; L, semilunar; C, cuneiform, P, pisiform. 



The Hand. The hand contains nineteen bones, five 

 metacarpal bones, one for each finger and the thumb, 

 whose bases articulate with the lower row of wrist bones, 

 and fourteen phalanges, three for each finger and two 

 for the thumb, of which the first row articulate with the 

 metacarpal bones. They are all long bones and are 

 slightly concave anteriorly. When the hand is flexed it 

 is the heads of the metacarpal bones, not the bases of 

 the phalanges, that are so prominent, the head of the 

 third metacarpal being most prominent. 



The metacarpals are seldom fractured, though bad 

 fractures occasionally occur. In comminuted fracture 

 nothing can be done but remove the bone. If the peri- 

 osteum is left the bone will grow again. Two diseases 



