122 



OSTEOLOGY 



Time 



of 

 appearance 



Time 



of 

 union 



In 



number of 

 centers 



In 



mode of 

 union 



1 for manubrium 



6lh month 



4 for body - 7th month 



4} 



5 1st year after birth 



1 for. xiphoid \ 



process f^** to ^tk year 



FIG. 118. Ossification of the sternum. 



Rarely unite, except in old age 

 i- Between puberty and the 25th year 



Soon after puberty 



Partly cartilaginous to advanced life 

 FIG. 119 



for first piece, two or more centers 



for second piece, usually one 



for third \ 



, f2, plac.ed laterally 

 for fourth] 



for fifth 



FIG. 120. Peculiarities. 



1' 



Arrest of ossification of lateral 'pieces, 

 producing : 



Sternal fissure, and 

 Sternal foramen 



Fio. 121 



