1002 THE NERVOUS SYSTEM 



Splanchnic efferent fibres from the rhombencephalon pass outwards to the sym- 

 pathetic in the roots of the facial, glosso-phiiryngeal, vagus, and spinal accessory 

 nerves, all of which have more or less irregularly disposed communicating ranu. The 

 ganglia of origin of the vagus, more than perhaps any other nerve, both give origin 

 to and receive impulses from splanchnic efferent fibres. Likewise, twigs of other 

 cranial nerves, especially of the trigeminus, connect with the small sympathetic 

 ganglia of the 'head. Themeningeal branches given by certain of the cranial nerves 

 contain vaso-motor fibres, and these correspond to the sympathetic fibres in the 

 recurrent branches and in the roots of the spinal nerves. 



FIG. 718. DIAGRAM SHOWING THE COURSE AND CONNECTIONS OF SYMPATHETIC 



NERVE-FIBRES. 



SPINAL GANGLIOX 



POSTERIOR 

 PRIMARY - 

 DIVISION 



ANTERIOR 

 PRIMARY 



DIVISION 



VASO-MOTOR, 

 PILO-NOTOR AND 

 SECRETOR Y FIBRES 



. VASO-MOTOR ( 



IX HOHtiM, HOUT OF SPINAL KERVK (fltOJl- 

 ABLY RARE) 



VENTRAL XERVE ROOT 

 U 



GREY RAMUS 



COMMUNICA NS 



WHITE KAMI'S 

 COMMUXICAKS 



WHITE RAMUS 

 COMMUNICANS 



GREY RAMUS 

 COMMUNICANS 



SYMPATHETIC TRUNK 



SYMPATHETIC TRVNH 



SYMPA T11ET1C GAXGLION 



PERI I'll ERA L AXXOCIA TIVE 

 SAUL'S 



SYMPATHETIC TRUNK 



SYMPA TIIETIC GANGLION 



vr.iurni-.r.A L ASSO- 

 CIATIVE RAMI'X 



ISTKKXEIII- 

 .1 jv; t;AN- 



TERMINAL GANGLION AND PLEXUS 

 IX PERIPHERAL ORGAN 



From the above it may be seen that the ganglia and connecting trunks and rami 

 of the sympathetic system may be divided as follows: (1) The two sympathetic 

 trunks lying proximal to and parallel with the vertebral column; (2) the great 

 prevertebral plexuses, of which there are roughly three, one in the thorax, one in 

 the abdomen, and one in the pelvic cavity (fig. 716), each of which is subdivided; 

 (3) the numerous terminal ganglia and plexuses situated either within or close to 

 the walls of the various organs; (4) the trunks and rami connecting the ganglia with 

 each other and thus contributing to the plexuses, or connecting the ganglia with 



