THE SPINAL NERVES. 177 



hrachialis) arise at the level o£ the second vertebra and leave the 

 vertebral canal between the second and third vertebrae. 



(3) The roots of the third nerve arise from the cord between the 

 second and third vertebrae, and pass out between the third and 

 foiu'th vertebrae. 



(4) The fourth nerve arises by its two roots at the level of the 

 fourth vertebra, and quits the vertebral canal between the fourth 

 and fifth vertebrae. 



(5) The fifth nerve arises opposite the fourth vertebra, and passes 

 outwards and slig-htly backwards to the foramen between the fifth 

 and sixth vertebrae. 



(6) The roots of the sixth nerve are attached to the cord opposite 

 the fourth vertebra, and leave the vertebral canal between the 

 sixth and seventh vertebrae. 



(7) The seventh nerve arises from the cord at a point between 

 the fourth and fifth vertebrae, and leaves the canal between the 

 seventh and eighth vertebrae. 



(8) The eig-hth nerve quits the cord at a point opposite the arti- 

 culation between the fifth and sixth vertebrae, then rims backwards 

 to the eighth vertebra, and escapes between this and the ninth 

 vertebra. 



(9) The ninth nerve arises at the level of the sixth vertebra, and 

 passes out between the sacrum (ninth vertebra) and the urostyle. 



(10) The tenth nerve {N. cocct/geus) arises from the cord immedi- 

 ately behind the ninth nerve and opposite the sixth vertebra, and 

 courses along-side the terminal filament to pass out through a fora- 

 men in the urostyle [canalis coccygeus). 



b. [The Spinal ganglia [Ganglia intervertehralia). 



At their exit from the intervertebral foramen the two roots of 

 each nerve unite and bear a g-ang-lionic enlargement, which is in 

 intimate connection with the dorsal root, but is merely in contact 

 with the ventral root. The ganglia lie ^ in the large intervertebral 

 depressions, upon the under surface of the Proc. obliqui, above and 

 behind, being in relation with the bodies of the vertebrae internally, 

 and the Musculi intertransversarii externally (Fig. 119); ventrally 

 the ganglia are, more or less, covered by the ' periganglionic glands.^ 

 The ganglia vary much in size ; that of the first spinal nerve is the 



' The Ganc/l. coccygeum is in the urostyle. 

 X 



