208 



COMPARATIVE ANATOMY 



forms and arrangement of the cervical vertebrae permit greater freedom 

 of movement than is possible in other parts of the column. The spinous 

 process of each cervical vertebra except the last is forked or bifid. 



Only the twelve thoracic vertebrae carry ribs. A pit in the centrum 

 articulates with the head of the rib and a similar pit at the extremity of the 



INFERIOR 

 VERTEBRAL NOTCH 



\MNFERIOR 

 ^ARTICULAR 

 PROCESS 



Fig. 164. — Various human vertebrae A-D. A represents an atlas vertebra, superior 

 surface; 5 is a cervical vertebra, superior surface; C-C a thoracic vertebra in lateral and 

 superior aspect; D-D a lumbar vertebra in lateral and superior aspect. (Redrawn 

 after Sobotta.) 



transverse process articulates with the tubercle of the rib. The head of 

 most ribs articulates with two adjacent centra. 



The five lumbar vertebrae are the largest. Short ribs fuse with them 

 to form conspicuous transverse processes. The neural arches of these 

 vertebrae have mammillary and accessory processes in addition to 

 articular. 



