CHAPTER V. 



T RU isr K. 



Supporting the head at the anterior extremity and 

 terminating posteriorly by the tall ; it has for base, od 

 the median line a series of bones called vertebrae, and 

 is composed of three cavities; the thoracic; the ab- 

 dondnalj separated by the diaphragm muscle ; and the 

 pelvic cavity, a dependance of the abdominal. 



Vertebrie — General characters. — They are single 

 bones perforated by the vertebral foramen, which in the 

 series forms the vertebral canal. Division : A body 

 and annular portion. TJie body has two faces : one 

 superior with two triangular surfaces and two grooves« 

 for venous sinuses ; the inferior with a crest sometimes 

 called the inferior spinous process. It has two ex- 

 tremities : an anterior with a round head more or less 

 prominent, one posterior with a cavity for the reception* 

 of the head. The antudaafcportion has an internal 

 surface, concave and forrifetg the vertebral foramen '; 



