28 ELEMENTARY ANATOMY. [LESS. 



looks mainly backwards. This is called the superior articular 

 process? or prezygapophysis, and each dorsal vertebra has, 

 of course, a pair of such. 



From the lower- and outer side of each lamina a small 

 process projects downwards, with a smooth surface on it 

 which looks mainly forwards. This is called the inferior 

 articular process, or postzygapophysis, and there are two to 

 every vertebra of the back. 



The articular surfaces of the two inferior articular pro- 

 cesses are applied to the articular surfaces of the two 

 superior articular processes of the next vertebra below. 

 Ligamentous fibres bind together the margins of the apposed 

 articular surfaces, between which is placed a sac containing 

 synovial fluid. 



The upper margin of each pedicle is somewhat concave, while 

 its lower margin is more so. In this way, when the vertebrae 

 are naturally articulated together, a rounded opening appears 

 between each pair of adjacent pedicles. These openings give 

 exit to spinal nerves coming out from the spinal marrow 

 enclosed within the neural arches. 



Two other articular surfaces on each side should be noted : 

 one at the outer side of the posterior and outer angle of the 

 centrum at its junction with the pedicle, the other at the 

 anterior aspect of 'the end of the transverse process. The 

 first of these articular sources is termed " capitular? and the 

 second " tubercular? for reasons which will appear later. 



The diameter of the centrum from side to side exceeds but 

 little its diameter from behind forwards. 



Fie. 40. A CERVICAL VERTEBRA. 



c, centrum ; s, neural spine ; /, neural lamina ; d, posterior or tubercular 

 transverse process, or diapophysis ; /*, anterior (or capitular) transverse pro- 

 cess, or parapophysis ; d' and/', "tubercles;" z, prezygapophysis. 



9. Of the seven CERVICAL VERTEBRAE, the first two are 

 sufficiently exceptional to demand separate notice. Any 



1 From Trpof, tvyov, a yoke, and uTrdf i'<nc. 



