1016 THE NERVOUS SYSTEM 



cceliac plexus, accompanies the left gastric (coronary) artery along: the lesser curva- 

 ture of the stomach. Its filaments anastomose with filaments of the vagus nerves 

 and with the plexus that accompanies the right gastric (pyloric) artery (fig. 721), 

 and it gives fibres to the walls of the stomach which connect, within the walls, 

 with the delicate gangliated plexus myentericus and plexus submucosus (plexuses 

 of Auerbach and Meissner). 



(3) The inferior gastric plexus receives from the splenic plexus filaments that 

 accompany the left gastro-epiploic artery. It gives filaments to the walls of the 

 stomach, and communicates with filaments from the vagus nerves and with the plexus 

 that accompanies the right gastro-epiploic artery. 



(4) The hepatic plexus receives filaments from the cceliac plexus and from the 

 left vagus. It accompanies the hepatic artery and gives fibres that form plexuses on 

 the branches of the artery and on their ramifications within the liver. It also gives 

 filaments to the portal vein (fig. 721). 



The splenic or lienal plexus is formed by filaments from the cceliac plexus, the 

 left cceliac (semilunar) ganglion, and from the right vagus. It accompanies the 

 splenic artery and gives filaments which form plexuses on the branches of this artery, 

 and which pass with the branches to supply fibres to the stomach and the pancreas 

 (fig. 721). 



(5) The superior mesenteric plexus is formed chiefly by filaments from the 

 lower part of the cceliac plexus, but it also receives fibres from the right vagus and 

 fibres direct from the cceliac (semilunar) ganglia. At the origin of this plexus, 

 behind the superior mesenteric artery, lies the superior mesenteric ganglion (fig. 721). 

 The filaments of the plexus, which are white and firm, accompany the superior 

 mesenteric artery and, following its branches and their ramifications, are distributed 

 to the walls of the small intestine, the caecum, and the ascending and transverse 

 colon. From the secondary plexuses that accompany the branches of the artery fibres 

 pass to form still other plexuses that lie near the wall of the intestine, between 

 the branches of the artery and between the layers of the mesentery. Filaments 

 pass with the branches of the arteries and from plexuses between them into the 

 intestinal wall, and there form between the longitudinal and circular muscle layers 

 of the intestine the fine gangliated plexus myentericus (plexus of Auerbach), and 

 filaments from this plexus form in the submucosa the delicate plexus submucosus or 

 plexus of Meissner. 



(6) The inferior mesenteric plexus is derived chiefly from the left side of the 

 aortic plexus. It descends upon the inferior mesenteric artery and gives off fila- 

 ments which accompany the branches of the artery and are distributed to the 

 descending colon and to the ilio-pelvic colon (figs. 721 and 722). The filaments 

 which accompany the left colic branch of the inferior mesenteric artery anastomose 

 with the filaments of the superior mesenteric plexus which accompany the middle 

 colic artery. The filaments which accompany the superior ha-morrhoidal artery 

 form the superior haemorrhoidal plexus. This plexus gives off the superior 

 hcemorrhoidal nerves (fig. 722) which supply the upper part of the rectum and anasto- 

 mose with the middle hcemorrhoidal plexus. 



THE HYPOGASTRIC PLEXUS 



The hypogastric plexus lies partly in the abdominal cavity and partly in the 

 pelvic cavity. It is formed chiefly by filaments continued downwards from the 

 aortic plexus, and by the pelvic splanchnics and peripheral branches from the 

 lumbo-sacral nerves and sympathetic trunk (fig. 716). The abdominal part of 

 this plexus consists of plexiform bundles of fibres descending between the common 

 iliac arteries and interlacing in front of the fifth lumbar vertebra to form a broad, 

 flattened, plexiform mass. In its extent it receives branches from the lumbar 

 ganglia of the sympathetic trunk. This plexiform mass then divides into two parts, 

 right and left, which descend into the pelvic cavity and which, by English authors, 

 are frequently designated as the pelvic plexuses. 



The pelvic parts of the hypogastric plexus (pelvic plexuses) lie at the sides of the 

 rectum in the male, and at the sides of the rectum and the vagina in the female. 

 They receive peripheral branches from the sacral ganglia of the sympathetic trunk 

 and efferent splanchnic fibres by way of the pelvic splanchnics from the second and 

 third or third and fourth sacral spinal nerves. Each pelvic part of the plexus accom- 



