68 



Bones of the Trunk. 



88. The Bony Portion of a True Rib. 



Each rib consists of a bony portion and a costal cartilage; the 

 bony portion has an external convex and an internal concave surface, a 

 superior rounded border, and an inferior border containing a groove, 

 Sulcus costalis , which deepens especially toward the vertebral extremity 

 of the rib ; the part where the outer edge of the groove is highest, is 

 called Crista costae. 



