CCELIAC PLEXUS. 765 



The coeliac plexus forms a considerable plexiibrrn mass surrounding the 

 coeliac artery. It consists of a dense meshwork of fibres with ganglia inter- 

 mingled, joined by numerous branches from the coeliac ganglion on each side, 

 and by branches from the right vagus nerve. It is continuous below with the 

 superior mesenteric and aortic plexuses. Investing the coeliac artery, it forms 

 subsidiary plexuses which are distributed along the branches of the artery. The 

 left gastric plexus supplies branches to the oesophagus and stomach ; the hepatic 

 plexus supplies branches to the liver and gall-bladder, stomach, duodenum, and 

 pancreas ; and the splenic plexus sends offsets to the spleen, pancreas, and stomach. 



Subordinate plexuses are formed on the aorta and its branches by nerves 

 derived from the coeliac ganglia and coeliac plexus. 



a. Plexus Phrenicus. The phrenic plexus consists of fibres arising from the 

 coeliac ganglion, and it accompanies the inferior phrenic artery. Besides supplying 

 the diaphragm, it gives branches to the suprarenal plexus, and on the right side 

 to the inferior vena cava on the left side to the oesophagus. It communicates on 

 each side with the phrenic nerve. At the junction of the plexus and the phrenic 

 nerve of the right side a ganglion is formed (phrenic ganglion). 



1. Plexus Suprarenalis. The suprarenal plexus is of considerable size. It is 

 mainly derived from branches of the coeliac ganglion, reinforced by nerves from 

 the inferior part of the coeliac plexus which stream laterally on the suprarenal 

 arteries. It is joined by branches from the phrenic plexus above and from the 

 renal plexus below. The nerves enter the substance of the suprarenal gland. 



c. Plexus Renalis. The renal plexus is derived from (1) branches of the coeliac 

 ganglion, and (2) fibres from the aortic plexus, extending laterally along the renal 

 artery to the hilum of the kidney. . It receives also the lowest splanchnic 

 nerve, and is connected by numerous branches to the suprarenal plexus. 



d. Plexus Mesentericus Superior. The superior mesenteric plexus is inseparable 

 above from the coeliac plexus, and is joined on each side by fibres from the coeliac 

 and aortico-renal ganglia. It is continuous below with the aortic plexus. A 

 separate detached ganglionic mass (superior mesenteric ganglion) is present in the 

 plexus. Accompanying the superior mesenteric artery it forms subordinate 

 plexuses around the branches of the vessel. The plexuses at first surround 

 the intestinal arteries, but near the intestine they form fine plexuses between 

 the layers of the mesentery, from which branches pass to the wall of the gut. 

 This plexus supplies the small intestine, caecum, vermiform process, ascending 

 and transverse portions of the colon. 



e. Plexus Aorticus Abdominalis. The aortic plexus is the continuation down- 

 wards of the coeliac plexus around the abdominal aorta. It is continuous above 

 with the coeliac and superior mesenteric plexuses ; it is reinforced by the peripheral 

 branches of the lumbar sympathetic trunk ; and it is connected with the hypo- 

 gastric plexus below by the hypogastric nerves. Besides investing and supplying 

 the aorta, the plexus is connected with various subordinate plexuses on the branches 

 of the artery. It contributes to the suprarenal and renal plexuses, and it gives 

 rise to the spermatic or ovarian, and the inferior mesenteric plexuses. 



Plexus Spermaticus. The spermatic plexus invests and accompanies the sper- 

 matic artery. It is derived from the aortic plexus, and receives a contribution 

 from the renal plexus. It supplies the spermatic cord and testis. 



Plexus Arterise Ovaricse. The plexus of the ovarian artery in the female arises 

 like the spermatic plexus. It accompanies the ovarian artery to the pelvis, and 

 supplies the ovary, broad ligament, and uterine tube. It forms communications in 

 the broad ligament with the uterine plexus (from the pelvic plexus), and sends 

 fibres to the uterus. 



Plexus Mesentericus Inferior. The inferior mesenteric plexus is a derivative from 

 the aortic plexus, prolonged along the inferior mesenteric artery. It forms sub- 

 ordinate plexuses on the branches of the artery (colic, sigmoid, and superior 

 hsemorrhoidal), and is distributed to the descending colon, iliac colon, pelvic colon, 

 and upper part of the rectum. 



