THE STERNUM 



137 



Fig. 165. — Ossification of the Sternum. 



A, common arrangement of the ossific centres. B, showing accessory centre in the manubrium 



sterni, and bilateral centres in the second, third, and fourth pieces of the body. 



Single centre for 

 manubrium sterni 



Single centre for each , 

 of the four pieces of\ 

 the body 



Single centre for ^—^ 



xiphoid process ^^i 



Centre for manubrium 

 sterni 



Accessory centre 



Single centre for first 

 piece of body 



, Bilateral centres for 



i^ second, third, and 



fourth pieces of body 



Single centre for 

 xiphoid process 



Fig. 166.— The Thorax. (Front view.) 



Superior thoracic aperture " .sf^ ■ 



? True ribs 



>False ribs 



Floating ribs 



