484 NERVOUS SYSTEM. 



lying on the vertebral column: some go to the cellular sub- 

 stance, others to the longus colli muscle, others to the aorta, 

 others to the cardiac and to the pulmonary plexuses. Among 

 these internal branches there are several which concur to form 

 the Splanchnic Nerves, of which there are two; the Great and 

 the Small. 



The Great Splanchnic Nerve arises, by filaments, from the 

 sixth to the ninth or tenth thoracic ganglions, inclusively; one 

 or more filaments corning from eaeh ganglion. They are di- 

 rected downwards and forwards on the sides of the dorsal ver- 

 tebrae, covered by the pleura, and unite, successively, into a 

 trunk about the eleventh dorsal vertebra. This trunk pene- 

 trates into the cavity of the abdomen, between the middle and 

 the internal head of the lesser muscle of the diaphragm, or by 

 the opening for the aorta. 



Having got into the abdomen, the great splanchnic divides 

 into several fasciculi, which, diverging from each other, are con- 

 cealed on the right side by the liver, and on the left by the sto- 

 mach. On each side of the aorta there is a large ganglion formed 

 by an assemblage of several smaller ones ; it is called the Semi- 

 lunar. Into it terminate, for the most part, these fasciculi : some 

 of them, however, go immediately into the solar plexus, which 

 emanates from the semi-lunar ganglion. 



The Small Splanchnic Nerve is derived, by filaments, from 

 the tenth and the eleventh thoracic ganglions. Having united, 

 they penetrate the crus of the diaphragm, and, reaching the ab- 

 domen, the trunk is divided into two branches, of which the 

 uppermost ascends to join the great splanchnic before its divi- 

 sion, and the lower descends to join the renal plexus. 



Posterior Renal Nerves. -Besides these two splanchnic nerves, 

 it frequently happens that there are others which come from 

 the eleventh and twelfth thoracic ganglions, and from the com- 

 municating branch between the last thoracic and the first lum- 

 bar. They unite into a trunk which goes to the renal plexus, 

 and have been called, by Walter, the Posterior Renal Nerves, 



