132 



SPINAL COLUMN. 



is interposed. By this arrangement the chain of bones is 

 converted into a strong elastic central axis, more or less move- 



Fig. 121. 



Fig. 122. 



m different animals, ac- 

 cording to the general struc- 

 ture and habits of each. 



Fig. 121 exhibits a front 

 view of the spinal column of 

 man. It is of a pyramidal 

 form, the base of the pyramid 

 rests upon the sacrum, and 

 the apex supports the skull. 

 We observe, likewise, that the 

 diameter of the bodies of the 

 vertebrae differs in different 

 regions, being broad in the 

 neck, narrow in the back, 

 and broad again in the loins. 



Fig. 122 represents a pos- 

 terior view of the spinal co- 

 lumn. The different forms of 

 the neurapophyses, in the cer- 

 vical, dorsal, and lumbar re- 

 gions, are here shewn. They 

 are observed to project back- 

 wards and a little downwards 

 in the neck ; they lie obliquely 

 downwards in the back, and 

 stand backwards in the loins. 

 On each side of the neural 

 spines, a groove is seen formed 

 by a junction of the arches of 

 all the vertebrae ; bounded 

 internally by the neural&pmes, 

 and externally by the para- 

 popliyses ; in this groove the 

 muscles are lodged that im- 

 part motion to the column. 



Fig. 1 23 is a lateral view 

 of the spinal column, which 

 presents anteriorly two con- 

 vex, and one concave surface. 



