Chap. 9.} Bones of tie Hand. 131 



in two directions. The radius is fo intimately con- 

 nected with the hand, and is fo much employed In its 

 principal motions, that it has been called manubrium 

 waxus, or the handle of the hand. Without this pe- 

 culiar mechanifm, the motions of the fore-arm would 

 be as confined as thofe of the leg ; but providence, 

 which has preferred the more firm and fecure ftruc- 

 ture in a part which was deflined to fupport the body, 

 has adapted the fore-arm, by this beautiful and admi- 

 rable contrivance, for the performance of a number of 

 motions, with which a hinge -joint would be quite in- 

 compatible. 



The bones of the hand are divided into thofe of the 

 carpus, metacarpus, and fingers. The carpus or wrift 

 is formed of eight bones, which are fmall, of irregular 

 lhapes, and diftinguiflied into two feries. The form 

 of the carpus isfquare ; that furface, which is contigu- 

 ous to the palm of the hand, is concave, the oppofite 

 is convex. Each of the two feries of bones, which, 

 compofe the carpus, confiils of four pieces. The firfl 

 feries, or that which is placed next die bones of the 

 fore-arm, confifts of the os naviculare, the os femilu- 

 nare, the os cuneiforme, and the os pififorme. The 

 bones, which form the other feries, are the os multan- 

 gulum majus, the os multangulum minus, the os ca- 

 pitatum, and the os cuneiforme. Thefe bones are co- 

 vered with cartilage, and are varioufty articulated with 

 the bones with which they are in contact. The prin- 

 cipal ufe of fo great a number of bones in the wrift is 

 to render the hand more flexible. The back part of 

 the hand is convex, for greater firmnefs and flrength ; 

 the palm concave, fbr containing more furely and con- 

 veniently fuch bodies as we take hold of. The upper 

 part of the hand has an obfcure motion in comparifon 

 the remainder, and ferves as a bafe to the fingers. 

 K 2 With 



