66 



THE HUMAN BODY. 



by the rings of the successive vertebrae lies the spinal cord. 

 Projecting from the dorsal side of the neural arch is a long 

 bony bar, Ps, the spinous process: and the projections of these 

 processes from the various vertebrae can be felt through the 

 skin all down the middle of the back. Hence the name of 

 spinal column often given to the whole back-bone. 



Six other processes arise from the arch of the vertebra: two 

 project forwards, i.e. towards the head; these, Pas, are the 

 anterior articular processes and have a smooth surface, 

 covered with cartilage, on their dorsal sides. A pair of sim- 



I's 



FIG. 16. 



FIG. 15. 



FIG. 15. A dorsal vertebra seen from behind, i.e. the end turned from the 

 head. 



FIG. 16. Two dorsal vertebrae viewed from the left side, and in their natural 

 relative positions. C, the body; A, neural arch; Fv, the neural ring; Ps. spi- 

 nous process ; Pas, anterior articular process : Pew, posterior articular process ; 

 ft, transverse process; Ft, facet for articulation with the tubercle of a rib; 

 Fes, Fci, articular surfaces on the centrum for articulation with a rib. 



ilar posterior articular processes, 'Pai, runs back from the 

 neural arch, and these have smooth surfaces on their ven- 

 tral aspects. In the natural position of the vertebra, the 

 smooth- surfaces of its anterior articular processes fit upon 

 the posterior articular processes of the vertebra next in 

 front, forming a joint, and the two processes are united 

 by ligaments. Similarly its posterior articular processes 

 form joints (Fig. 16) with the anterior articular processes 

 of the vertebra next behind. 



