230 DETAILED SYNTHESIS. 



the same time ; it is the simplest arrangement imagina- 

 ble, yet how complete ! 



401. THE RADIUS is JOINTED to the wrist (carpus), 

 'that does not touch the ulna, so that when the radius 

 turns, the hand is carried with it. Thus is obtained an ex- 

 ceedingly useful motion, as in turning a key, gimlet, etc. 



402. THE HAND is JOINTED to the radius by a partial 

 ball and socket-joint, or compound hinge-joint, and thus 

 can be bent up and down and from side to side. 



403. THE CARPUS is CONSTRUCTED of eight bones, in 

 two rows of four each. (See the appropriate Figs, and 

 descriptions.) 



404. THE CARPAL BONES ARE CONSTRUCTED spongi- 

 fonn within and a thin dense layer at their surface. Their 

 joints are supplied with cartilages, and they are bound 

 strongly together by ligaments. 



405. From the carpal the METACARPAL BONES ex- 

 tend to the bones (phalanges) of the fingers, of Avhich 

 there are two in the thumb and three in each of the fin- 

 gers, jointed by ball and socket and hinge joints, fur- 

 nished with cartilages, synovial membranes, and bound 

 together with ligaments, limiting the bones to their ap- 

 propriate motions. 



406. THE ENTIRE SKELETON, with the exception of 

 the U-shaped bone (hyoid), has been passed under no- 

 tice ; that bone can be better described in connection 

 with the organs of voice and the framework of the lar- 

 ynx, which will best follow the organs of respiration. 



407. THE FRAMEWORK OF SOME PARTS, the ear, tip 

 of the nose, the larynx and trachea, are wholly composed 

 of cartilage that never becomes ossified. 



Remark. This seems to be remarkably fortunate, for men never live 

 to be so old as not to be fond of thrusting their noses into other people's 

 affairs, and these organs would be very often fractured if they ever lost 

 their elasticity. 



401. How _? 402. How -? 408. How ? 404. How ? 405. What said 

 of - ? 406. What said ? 40T. What said ? 



