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HANDBOOK OF ANATOMY 



The eleventh and twelfth ribs are very much' shorter and 

 smaller than the others. Their anterior extremities are pointed 

 and tipped with cartilage, but are free and non-articulating. 



Ossification. The shaft is almost completely ossified before- 



FIG. 33. THORAX. 



birth. Secondary centres for the head and tubercle appear 

 before puberty, and the whole rib is fused by the twenty -fifth 

 year. 



The Thorax as a whole is barrel-shaped, narrower above than 



