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PHYSIOLOGY. 



cause they belong to the back ; and the last five are the 

 lumbar, because they are situated in the loins. The bones 

 comprising these classes, differ somewhat from each other in 

 shape ; a description of the dorsal pieces will prove sufficient 

 for our purpose. 



A lateral view of the spine divided into its cervical, dorsal, and lura 

 bar portions. 



27. Each of these twelve bones consists of a body, four 

 articulating processes, two transverse processes, and one spi- 

 nous process. The body is formed of soft and spongy bone, 

 which is circular before, flat towards the sides, hollowed out 

 behind into a crescent shape for containing the spinal mar- 

 row, and concave above and below for the accommodation 

 of the intervertebral substance. On the side of the bone are 



