THE HYPOGASTRIC PLEXUS 1045 



(4a) The spermatic plexuses (fig. 790) are formed by fibres from the renal and aortic 

 plexuses. They accompany the spermatic arteries and are joined at the abdominal inguinal 

 (internal abdominal) ring by fibres that have passed along the vas deferens from the pelvic 

 plexuses. Their terminal filaments are distributed to the testis and the epididymis. 



(4b) The ovarian plexuses are formed in the female like the spermatic plexuses in the 

 male. They accompany the ovarian arteries and, in the broad ligament, receive fibres from 

 the utero-vaginal plexus. They supply the ovaries, the broad ligaments, and the Fallopian 

 tubes, and send some fibres to the fundus of the uterus, where they become continuous with 

 the utero-vaginal plexus. 



The unpaired subordinate plexuses: — (1) The abdominal aortic plexus is formed by 

 two strands of fibres which descend along the sides of the aorta and communicate with each 

 other across its ventral aspect. It is connected above with the renal plexu.ses, and it receives 

 peripheral branches from some of the lumbar ganglia of the sympathetic trunk on each side. It 

 often contains a number of ganglia, which are situated at the points where the peripheral 

 branches join the plexus, and it terminates below, chiefly by anastomoses with the hypogastric 

 plexus (figs. 790 and 791). Besides giving filaments to the inferior vena cava, it also gives 

 fibres that form plexuses along each of the branches of the aorta. The fibres that pass from 

 the lower end of the aortic plexus upon the common iliac artery form the iliac plexus, which 

 is continued along the femoral artery as the femoral plexus, and still further along the popliteal 

 artery as the popliteal plexus. 



(2) The superior gastric (coronary) plexus, receiving filaments from the ccehac plexus, 

 accompanies the left gastric (coronary) artery along the lesser curvature of the stomach. 

 Its filaments anastomose with filaments of the vagus nerves and with the plexus that accom- 

 panies the right gastric (pyloric) artery (fig. 790), and it gives fibres to the walls of the stomach 

 which terminate within the walls, about the cell bodies of the delicate gangliated plexus myen- 

 tericus and plexus submucosus (plexuses of Auerbach and Meissner). The axones of these 

 supply the smooth muscle of the stomach walls and its vessels. 



(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, which terminate 

 as in the superior gastric plexus, and it receives filaments from the vagus nerves and from 

 the plexus that accompanies the right gastro-epiploic artery. 



(4) The hepatic plexus receives filaments from the ca?nac 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 and gives secretory fibres to the Uver cells. 

 It also gives filaments to the portal vein (fig. 790). 



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

 (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. 790). 



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

 of the coeliac plexus, but it also receives fibres from the right vagus and fibres direct from the 

 cceliac (semilunar) gangha. At the origin of this plexus, dorsal to the superior mesenteric 

 artery, lies the superior mesenteric ganglion (fig. 790). 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 ganghated plexus myen- 

 tericus (plexus of Auerbach), and filaments from this plexus form in the submucosa the dehcate 

 plexus submucosus or plexus of Meissner. From these latter plexuses fibres arise which ter- 

 minate upon the gland cells and smooth muscle fibres of the intestinal wall and its vessels. 

 The white appearance of the filaments of the superior mesenteric plexus is due to the large 

 number of cranio-spinal sensory and visceral motor fibres (vagus especially) in it. 



(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 filaments which accompany the 

 branches of the artery and are distributed to the descending colon and to the ilio-pelvic colon 

 (figs. 790 and 791). The filaments which accompany the left colic branch of the inferior mesen- 

 teric artery anastomose with the filaments of the superior mesenteric plexus which accompany 

 the middle colic artery. The filaments which accompany the superior hsemorrhoidal artery 

 form the superior hsemorrhoidal plexus. This plexus gives off the superior hce trior rlioidal 

 nerves (fig. 791) which supply the upper part of the rectum and anastomose with the middle 

 hcemorrhoidal plexus. 



4. 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 downward from the 

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

 lumbo-sacral nerves and sympathetic trunk (fig. 784). 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 



