OSSEOUS SYSTEM OF MAMMALIA. 73 



into two rows, a basal and an anterior, each containing four. All 

 the bones of the basal row, excepting one (the little os pisiforme), are 

 connected with the fore-arm, at the moveable articulation of the wrist. 

 The basal row consists of the os scaphoides (1) ; the os lunare (2) ; 

 the os cuneiforme (3) ; the os pisiforme (4). The anterior row con- 

 tains the trapezium (5) ; the os trapezoides (6) ; the os magnum (7) ; 

 the os unciforme (8). 



The os scaphoides, or scaphoid bone, so called from its fancied resem- 

 blance to a hollow oblong vessel, or boat (Sxa^, vas oblongum, or 2/ca^oy, 

 fossa), is united to the radius of the fore-arm on one part, and to several 

 of the carpal bones on the other ; and, among them, to the os lunare, so 

 termed from the crescent shape of that side which is in contact with the 

 scaphoid bone : it is, also, articulated to the radius. The os cuneiforme, 

 or wedge-shaped bone, is in apposition with the extremity of the other 

 bone of the fore-arm, termed the ulna ; and has, on its internal surface, 

 the fourth bone of the basal row, viz., the os pisiforme. This little bone 

 derives its name from its resemblance, in figure, to a pea. The tendon of 

 that muscle of the wrist, called flexor carpi ulnaris, is inserted into it, and 

 it gives rise to a muscle for drawing down the little finger, termed ab- 

 ductor minimi digiti. Of the anterior row, the first in order is the os tra- 

 pezium, having four unequal sides at its back part, whence it has obtained 

 its name. It rests upon the scaphoid bone, and, in a pulley-like depression, 

 receives the head of the first or metacarpal bone of the thumb. To the 

 trapezium succeeds the os trapezoides, so called from the irregularly 

 quadrangular figure of its back part : it sustains the first metacarpal bone, 

 viz., that of the first finger. The next is the os magnum, or large bone of 

 the wrist : it sustains the second metacarpal bone, and rests on the 

 scaphoid and lunar bones. The last is the os unciforme, or hooked bone, 

 which obtains its name from a thin, broad, excavated projection, standing 

 toward the palm, and affording, in its sulcus, both a channel, or passage, 

 and a protection to the tendons of certain muscles of the fore-arm, which 

 draw down the fingers : it rests upon the os lunare and os cuneiforme, 

 and supports the two last metacarpal bones, viz., those of the third and 

 little fingers. The metacarpal bones are based upon the carpus, on which 

 they have an obscure and limited motion. Their number, of course, cor- 

 responds with those of the four fingers and the thumb : they are, in shape, 

 long and round, enlarging into heads at each extremity, where they are 

 in contact with each other, a space intervening between the bodies : in 

 these spaces are lodged certain small muscles, termed interossei, passing 

 along, from the carpus to the fingers. 



The orderly disposition of the bones of the fingers, each into three 

 rows, has suggested their appellation of phalanges, or phalangal bones, 

 in allusion to the martial phalanx of the Greeks. The first phalangal 



