520 NEUROLOGY, 



by the side of the psoas parvus muscle, it is continued in the 

 abdominal cavity by the lumbar portion. During its passage 

 through the thorax, seventeen small fusiform ganglia, one at each 

 intercostal space, present themselves. The afferent branches, from 

 one to three generally, are furnished by the inferior branches of the 

 dorsal nerves, which pass through the intervertebral foramina to 

 each ganglion. The emergent branches are some small fibres 

 which supply the pleura, and the large and small splanchnic nerves. 



The Great Splanchnic nerve is detached from the sixth or 

 seventh ganglion, and receives, in its backward course, additional 

 fibres from all the other ganglia except the last tAvo or three. It 

 enters the abdominal cavity in company with the psoe muscles, 

 when it presents a small ganglionic mass, and is then bent 

 inwards, and terminates in a large ganglion, the semilunar or 

 solar ganglion, between the coeliac axis and the anterior mesen- 

 teric trunk. 



The Semilunar ganglia, the largest of all the sympathetic 

 ganglia, are elongated from before backwards, and flattened from 

 above downwards. They communicate by means of a large and 

 strong grey cord, which passes behind the mesenteric trunk, and 

 by a number of filaments which proceed from side to side in 

 front of this artery. On the inferior face of the aorta these 

 filaments form the solar 'plexus, which receives branches from the 

 superior cord of the jDar vagum, and is divided at its periphery 

 into numerous secondary plexuses, from which many ramifica- 

 tions interlace and unite in a very complex manner round the 

 divisions of the arteries, which they accompany into the neigh- 

 bouring organs. 



Of these secondary plexuses, the gastric distributes its branches 

 to the stomach, on the walls of which they communicate with the 

 pneumogastric nerve ; the hepatic supplies the liver, duodenum, 

 pylorus, and pancreas; the splenic, the spleen and part of the 

 stomach ; the anterior mesenteric, the largest of all, the viscera 

 supplied by the anterior mesenteric artery ; and the renal and 

 suprarenal, double and less distinct than the others, supply the 

 kidneys and suprarenal capsules. 



The numerous strong branches which leave the solar plexus, 

 behind the anterior mesenteric artery, and run along the inferior 

 face of the aorta, frequently communicating with each other, form 

 the lumbo-aortic plexus, which unites with the posterior mesen- 

 teric plexus. 



