92 OSTEOLOGY 



The Metacarpal Bones or Bones of the Palm. 

 The metacarpal bones are five in number, from 1 to 5, 

 the first being the metacarpal bone of the thumb, the 

 fifth the metacarpal bone of the little finger. They 

 are long, cylindrical bones presenting a shaft, and an 

 upper and lower extremity. 



Articulations of Metacarpal Bones. 



First bone (proximal extremity) trapezium. 



[Trapezium, trapezoid, os mag- 

 Second bone (proximal extremity) i num. 



[Third metacarpal bones. 



Third bone (proximal extremity) ( S m f gnum ' S , econd and fourth 



\ metacarpal bones. 



Fourth bone (proxi.al extre m it y ) * ^T'^ ?' b! 

 Fifth bone (proximal extremity) 



The distal extremity of each metacarpal bone artic- 

 ulates with the corresponding proximal extremity of 

 the first phalanx below. 



The Phalanges of the Hand (Four Fingers, One 

 Thumb). The phalanges are fourteen in number, 

 three for each finger and two for the thumb. They 

 consist of a shaft and upper and lower extremity. 

 They are similar in shape to the metacarpal bones, 

 only smaller, and are held together by ligaments, re- 

 inforced by the fibrous sheaths of the flexor and exten- 

 sor tendons. The first bone articulates with its meta- 

 carpal bone above, and the second phalanx 'below; 

 the second with the first or proximal phalanx above 

 and the third or distal phalanx below; and the third 

 phalanx with the second phalanx above. Of course, 

 the first phalanx of the thumb articulates with the 

 metacarpal bone above and the second phalanx below; 

 the second phalanx articulates with the first phalanx 

 above; there being no third phalanx. 



All the long bones described have a nutrient canal 

 for the entrance of the nutrient artery. 



