DISSECTION OF THE ABDOMEN. 327 



corresponding to the coeliac axis, the companion veins of the divisions 

 of that artery behaving as follows : — 



The Splenic Vein is the upward continuation of the left gastro-omental 

 vein. After receiving the posterior gastric vein, it becomes one of the 

 roots of the vena portae, previously forming a short trunk by union 

 with the posterior mesenteric vein. 



The Anterior Gastric Vein joins the vena portse in the posterior 

 fissure of the liver. 



The Right Gastro-omental Vein is continuous with the left vein of 

 the same name, in the texture of the great omentum, opposite the 

 middle of the great curvature of the stomach. It receives gastric, 

 omental, duodenal, pyloric, and pancreatic branches, all of which 

 run in company with the arteries of the same names ; and then, 

 above the pancreas, it joins the portal vein. 



The (Esophageal Nerves. These nerves are the backward con- 

 tinuation of the vagus, pneumogastric, or 10th cranial nerves. They 

 reach the abdominal cavity by passing through the foramen sinistrum 

 of the diaphragm, in company with the oesophagus and the pleuro- 

 oesophageal branch of the gastric artery. The inferior nerve forms 

 at the lesser curvature of the stomach a plexus whose filaments pass 

 mainly to the right sac ; while the superior, after giving branches 

 to the left sac, joins the solar plexus. 



The Splanchnic Nerves. On each side there are two splanchnic 

 nerves — a great and a small. Both are formed by efferent branches of 

 the dorsal portion of the sympathetic gangliated cord, and they reach 

 the abdomen by passing between the diaphragm and the psoas parvus 

 muscle. The great splanchnic nerves terminate in the semilunar 

 ganglia ; the small nerves pass directly to the solar plexus, or they 

 may be continued to the renal or the suprarenal plexus. 



The Semilunar Ganglia are the largest in the body. They are 

 placed one at each side of the lower face of the aorta, between the 

 coeliac and anterior mesenteric arteries. Each receives the great 

 splanchnic nerve of its own side, and the two ganglia communicate 

 by transverse branches across the lower face of the aorta. The 

 efferent branches which proceed from them form the solar plexus. 



The Solar Plexus is an intricate network of nerves and ganglia. 

 It is joined on each side by the lesser splanchnic nerve, and by the 

 terminal filaments of the superior oesophageal nerve. From the plexus 

 nerves pass to the abdominal viscera, and in doing so they run in 

 company with arteries. There is thus : a coeliac plexus, whose branches 

 reach the liver, pancreas, spleen, and stomach, by accompanying 

 the divisions of the hepatic, splenic, and gastric arteries; a renal 

 and a suprarenal plexus, which pass to the kidneys and suprarenal 

 bodies ; an aortic plexus, continued backwards on the aorta to join 



