34 



ELEMENTAR Y ANA TOMY. 



[LESS. 



summit of the sacrum, and then decreases very much more 

 suddenly. 



The anterior surface is broadest at the neck, the loins, and 

 sacrum, and bears no median prominences. 



The posterior surface bears a median series of spines, which 

 are longest in the last cervical vertebra and in the trunk. 

 They are all directed either downwards or backwards never 

 upwards. 



The true vertebrae, except the first two, are locked together 

 by articular processes and by the bodies, which latter are 

 united by intervertebral substances. No other articulations 

 exist between them. 



1 6. The breastbone, or STERNUM, extends along the front 



FIG. 46. RIGHT SIDE OF THE THORAX. 

 i 12, the ribs ; ms, the manubrium ; xp, the Xiphoid process. 



portion of the trunk in the middle line, but its size, com- 

 plexity, and importance are very much less than the back- 

 bone's. 



It receives the ends of the upper ribs, protecting the chest 

 in front, and sheltering the heart. 



