SECTION V 

 THE NERVOUS SYSTEM 



SPINAL NERVES 



HAVING studied the various organs of special sense and the 

 muscles by which we can react to the impressions received 

 through them, the general characters of the connecting 

 nerves between the central nervous system, and the various 

 structures involved, may now be considered. These nerves 

 may be classified as ingoing and outgoing, and they may 



FIG. 75. Structure of a Typical Spinal Nerve. P.R. , posterior root with ganglion ; 

 A.R., anterior root; S.L, ganglion of sympathetic chain; W.R., its white 

 ramus ; G.R., its grey ramus ; V.N., visceral nerve with collateral ganglion ; 

 S.N., somatic nerve. 



roughly be divided into those connected with the body wall 

 and its appendages and those connected with the viscera. 



General Structure. The arrangement of fibres may best 

 be understood by studying the constitution of one of the 

 typical spinal nerves coming off from, say the dorsal region, 

 of the spinal cord (Fig. 75). 



A posterior root (P.R.) comes off from the postero-lateral 

 aspect of the cord and has a swelling upon it, the ganglion 



