92 



BONES OF THE UPPER LIMB. 



Fig. 84. 



Fig. 84. OSSIFICATION OF THE BONES OF THE HAND. 



A, represents the state of the bones and cartilages at the period of birth. The carpus 

 is entirely cartilaginous. Each of the metacarpal bones and digital phalanges has its 

 primary centre of ossification. 



B, the state of the bones in a child at the end of the first year; the os magnum and 

 unciform bone have begun to ossify. 



C, the condition about the third year. Additional centres of ossification are seen in 

 the cuneiform and in the proximal epiphysis of the first and the distal epiphyses of the 

 other four metacarpal bones, and in the proximal epiphyses of the first row of phalanges. 



D, the condition at the fifth year. Additional centres have been formed, first in the 

 trapezium, and later in the semilunar bone, and in the middle and distal phalanges : 

 (the figure does not show them distinctly in the middle phalanges). 



E, the condition at about the ninth year. Additional centres have been formed in the 

 scaphoid and trapezoid bones, and the more developed epiphyses of the metacarpal bones 

 and phalanges are shown, in the first and second separately. 



1, os magnum ; 2, unciform ; 3, cuneiform ; 4, semilunar; 5, trapezium ; 6, scaphoid ; 

 7, trapezoid ; 8, metacarpal bones, the principal piece ; 8% four metacarpal epiphyses ; 

 8', that of the thumb ; 9, the first range of phalanges ; 9*, their epiphyses ; 9', that of 

 the thumb; 10, second range of phalanges ; 10', epiphysis of terminal phalanx of thumb; 

 11, terminal range of phalanges of the fingers; 11*, their epiphyses. 



