SOLAR PLEXUS. 699 



CORONARY PLEXUSES. The anterior coronary plexus, formed at first from the 

 fibres of the superficial cardiac plexus, passes forwards between the aorta and pul- 

 monary artery, and, having received an accession of fibres from the deep cardiac 

 plexus, follows the course of the left or anterior coronary artery. 



The posterior coronary plexus, derived chiefly from the left part of the deep car- 

 diac plexus, but joined by nerves from the right portion of that plexus, surrounding 

 the branches of the right coronary artery accompany them to the back of the heart. 



Nervous filaments ramify in great number under the lining membrane of the 

 heart. They are not so easily distinguished in man as in some animals. In the 

 heart of the calf or lamb they are distinctly seen without dissection, running in lines 

 which cross obliquely the muscular fibres. Remak was the first to observe that these 

 branches are furnished with small ganglia, both on the surface and in the muscular 

 substance. (Mailer's " Archiv," 1844.) 



SOLAR OR EPIGASTRIC PLEXUS. 



The solar or epigastric plexus, which is the largest of the prevertebral 

 centres, is placed at the upper part of the abdomen, behind the stomach, and 

 iii front of the aorta and the pillars of the diaphragm. Surrounding the 

 origin of the coeliac axis and the upper mesenteric artery, it occupies the 

 interval between the suprarenal bodies, and extends downwards as far as the 

 pancreas. The plexus consists of nervous cords, with several ganglia of 

 various sizes connected with them. The large splanchnic nerves on both sides, 

 and some branches of the pneumo- gastric, terminate in it. The branches 

 given off from it are very numerous, and accompany the arteries to the 

 principal viscera of the abdomen, constituting so many secondary plexuses 

 on the vessels. Thus diaphragmatic, coeliac, renal, mesenteric, and other 

 plexuses are recognised, which follow the corresponding arteries. 



Semilunar ganglia. The solar plexus contains, as already mentioned, 

 several ganglia ; and by the presence of these bodies, and their size, it is 

 distinguished from the other prevertebral plexuses. The two principal 

 ganglionic masses, named semtlttuor, though they have often little of the 

 form the name implies, occupy the upper and outer part of the plexus, one 

 on each side, and are placed close to the suprarenal bodies by the side of 

 the coeliac and the superior mesenteric arteries. At the upper end, which 

 is expanded, each ganglion receives the great splanchnic nerve. 



DIAPHRAGMATIC PLEXUS. The nerves (inferior diaphragmatic) composing this 

 plexus are derived from the upper part of the semilunar ganglion, and are larger on 

 the right than on the left side. Accompanying the arteries along the lower surface 

 of the diaphragm, the nerves sink into the substance of the muscle. They furnish 

 some filaments to the suprarenal body, and join with the spinal phrenic nerves. 



At the right side, on the under surface of the diaphragm, and near the suprarenal 

 body, there is a small ganglion, ganglion diaphragmatic um, which marks the junc- 

 tion between the phrenic nerves of the spinal and sympathetic systems. From this 

 small ganglion filaments are distributed to the vena cava, the suprarenal body, and 

 the hepatic plexus. On the left side the ganglion is wanting, but some filaments are 

 prolonged to the hepatic plexus. 



SUPRARENAL PLEXUS. The suprarenal nerves issue from the solar plexus and the 

 outer part of the semilunar ganglion, a few filaments being added from the diaphrag- 

 matic nerve. They are short, but numerous in comparison with the size of the body 

 which they supply : they enter the upper and inner parts of the suprarenal cap- 

 sule. These nerves are continuous below with the renal plexus. The plexus is 

 joined by branches from one of the splanchnic nerves, and presents a ganglion 

 (g<ingl. splanchnico-suprarenale}, where it is connected with those branches. The. 

 plexus and ganglion are smaller on the left than on the right side. 



