Bones of the Trunk. 



67 



87. The Sternum in Articulation with the Costal 



Cartilages. 



The Sternum is in articulation at its lateral borders with seven costal 

 cartilages. Only the first costal cartilage is continuous with the Sternum; the 

 others are articulated with the Sternum in synovial cavities; the articular facets 

 become shallower and shallower from the second to the seventh costal cartilage, 

 and the seventh is placed in a very small concavity at the point of union of 

 the Gladiolus and xiphoid appendix. 



The ribs whose cartilages articulate with the Sternum are called true, 

 Costae verae; those ribs whose cartilages articulate with each other, or those 

 which end free, without any articulation are called false, Costae spuriae. True 

 ribs are the upper seven pairs ; false ribs the lower five pairs. 



9* 



