THE EPIGASTRIC OR SOLAR PLEXUS. 875 



filaments are distributed with those vessels to the muscular substance of the 

 ventricles. 



The anterior coronary plexus is formed chiefly from the superficial cardiac 

 plexus, but receives filaments from the deep cardiac plexus. Passing forward 

 between the aorta and pulmonary artery, it accompanies the left coronary artery 

 on the anterior surface of the heart. 



Valentin has described nervous filaments ramifying under the endocardium ; 

 and Remak has found, in several mammalia, numerous small ganglia on the cardiac 

 nerves, both on the surface of the heart and in its muscular substance. 



The Epigastric or Solar Plexus (Figs. 512, 514). 



The Epigastric or Solar plexus supplies all the viscera in the abdominal cavity. 

 It consists of a great network of nerves and ganglia, situated behind the stomach 

 and in front of the aorta and crura of the Diaphragm. It surrounds the coeliac 

 axis and root of the superior mesenteric artery, extending downward as low as the 

 pancreas and outward to the suprarenal capsules. This plexus, and the ganglia 

 connected with it, receive the great splanchnic nerve of both sides, and some 

 filaments from the right pneumogastric. It distributes filaments which accompany, 

 under the name of plexuses, all the branches from the front of the abdominal 

 aorta. 



The semilunar ganglia of the solar plexus, two in number, one on each side, 

 are the largest ganglia in the body. They are large irregular gangliform masses 

 formed by the aggregation of smaller ganglia, having interspaces between them. 

 They are situated in front of the crura of the Diaphragm, close to the suprarenal 

 capsules : the one on the right side lies beneath the inferior vena cava ; the upper 

 part of each ganglion is joined by the greater splanchnic nerve, and to the inner 

 side of each the branches of the solar plexus are connected. 



From the epigastric or solar plexus are derived the following : 



Phrenic or Diaphragmatic plexus. ( Gastric plexus. 



Suprarenal plexus. Coeliac plexus < Splenic plexus. 



Renal plexus. ( Hepatic plexus. 



Spermatic plexus. Superior mesenteric plexus. 



Aortic plexus. 



The phrenic plexus accompanies the phrenic artery to the Diaphragm, which 

 it supplies, some filaments passing to the suprarenal capsule. It arises from the 

 upper part of the semilunar ganglion, and is larger on the right than on the left 

 side. It receives one or two branches from the phrenic nerve. In connection 

 with this plexus, on the right side, at its point of junction with the phrenic nerve, 

 is a small ganglion (ganglion diapTiragmaticuni). This ganglion is placed on the 

 under surface of the Diaphragm, near the suprarenal capsule. Its branches are 

 distributed to the inferior vena cava, suprarenal capsule, and hepatic plexus. 

 There is no ganglion on the left side. 



The suprarenal plexus is formed by branches from the solar plexus, from the 

 semilunar ganglion, and from the phrenic and great splanchnic nerves, a ganglion 

 being formed at the point of junction of the latter nerve. It supplies the supra- 

 renal capsule. The branches of this plexus are remarkable for their large size in 

 comparison with the size of the organ they supply. 



The renal plexus is formed by filaments from the solar plexus, the outer part 

 of the semilunar ganglion, and the aortic plexus. It is also joined by filaments 

 from the lesser and smallest splanchnic nerves. The nerves from these sources, 

 fifteen or twenty in number, have numerous ganglia developed upon them. They 

 accompany the branches of the renal artery into the kidney, some filaments on 

 the right side being distributed to the inferior vena cava, and others to the sper- 

 matic plexus on both sides. 



The spermatic plexus is derived from the renal plexus, receiving branches from 

 the aortic plexus. It accompanies the spermatic vessels to the testes. 



