ABDOMINAL CAVITY 363 



largest of the three, consists of the two coeliac (O.T. semilunar) 

 ganglia and the numerous nerve bundles which connect the 

 ganglia together. 



It lies at the level of the lower part of the last thoracic and 

 the upper part of the first lumbar vertebra, in front of the 

 crura of the diaphragm and the uppermost part of the 

 abdominal portion of the aorta, between the medial margins 

 of the suprarenal glands, and around the cceliac artery. 

 Numerous offshoots arise from it and pass either along the 

 adjacent arteries, or to the suprarenal glands and the kidneys ; 

 the offsets constitute the secondary plexuses. 



Ganglia Cceliaca (O.T. Semilunar Ganglia). The cceliac 

 ganglia are of irregular shape ; they are frequently broken up 

 into a number of connected segments, and they are so large 

 that they are frequently mistaken by students for lymph 

 glands. The upper extremity of each ganglion is joined by 

 the great__srjlanchnic nerve of the same side, whilst the lower 

 part, wKIch is often more or less detached, is connected with 

 the lesser splanchnic nerve. 



Plexus Gastricus Superior. The superior gastric plexus springs from 

 the front of the coeliac plexus. It accompanies the left gastric artery to 

 the lesser curvature of the stomach and distributes twigs to both surfaces 

 of that viscus. 



Plexus Hepaticus. The hepatic plexus also springs from the front of 

 the central part oTthe coeliac plexus. It is joined by twigs from the left 

 vagus nerve, and accompanies the hepatic artery, the portal vein and the 

 bile-duct to the liver. At the lower margin of the lesser omentum, it 

 gives off twigs which accompany the gastro-duodenal artery and its right 

 gastro-epiploic branch ; they constitute the inferior gastric plexus. 



Plexus Lienalis. The splenic plexus, like the superior gastric and the 

 hepatic plexuses," springs from the median and anterior part of the coeliac 

 plexus. It accompanies the splenic artery to the spleen, and is joined by 

 twigs from the right vagus nerve. It gives offshoots along the various 

 branches of the artery. 



Plexus Benalis. Each renal plexus consists of numerous nerves which 

 spring chleHyTfom the lateral part of the corresponding coeliac ganglion. 

 Some will be found, however, arising from the strands of the coeliac plexus 

 and others from the aortic plexus. The lowest or third splanchnic nerve, 

 when it is present, joins the renal plexus. Thus constituted, the filaments 

 of the renal plexus run with the renal artery to the hilum of the kidney, 

 and are distributed within the gland substance. Several twigs are given 

 also to the spermatic plexus. A few scattered ganglia are usually found in 

 connection with the renal plexus. 



Plexus Suprarenalis. The dissector will be struck with the large 

 number of nerve's which supply the suprarenal glands. They are derived 

 chiefly from the coeliac ganglion of the same side, but many come from the 

 strands of the cceliac plexus. Each suprarenal plexus is directly con- 

 tinuous below with the renal plexus, and it is connected above with the 

 phrenic plexus. The lowest splanchnic nerve usually contributes a 



