THE HUMAN SKELETON. 77 



situated the four articulating processes, each bone being con- 

 nected with the two immediately adjoining it. Two of these 

 processes are situated near its upper surface to articulate 

 with corresponding processes belonging to the bone above, 

 and two are placed near its under surface to join with those 

 of the bone below. The two superior articulating processes 

 of one vertebrae are thus connected with the two inferior 

 articulating processes of another, and these points of union 

 not only co-operate with the intervertebral cartilages in 

 keeping these two vertebrae together, but permit a slight 

 rotatory motion of the one upon the other* The spinous 

 process projects directly backwards from the body of the ver- 

 tebrae, and may be felt externally by passing the hand along 

 the spine ; the two transverse stand out on either side, and 

 have the ends of the ribs attached to them. 



A vertebra of the neck ; a, body of the bone ; 6, the spinal process ; 

 c, d, the transverse processes double, showing circular holes for the 

 passage of the vertebral artery ; e, e. the superior ; /, /, the articular, 

 or oblique processes ; g, the spinal hole for the spinal marrow. The 

 roots of the articular processes are hollowed out above and below 

 into notches ; and these, when the bones are fitted together, form aper- 

 tures on each side of the spine, through which the nerves pass out from 

 the spinal canal. 



7* 





