SOLAR PLEXUS. 375 



consists of nervous cords, with several ganglia of various sizes connected with them. 

 The large and small 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, 

 cceliac, mesenteric, and other plexuses are recognised, which follow the corresponding 

 arteries. 



Semiluiiar ganglia. The solar plexus contains, as already mentioned, several 

 ganglia (ganglia cvdiaca) ; and by the size of these bodies it is distinguished from 

 the other prevertebral plexuses. The two principal ganglionic masses, named 

 semilunar, 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 cceliac and the superior mesenteric arteries. 

 At the upper end, which is expanded, each ganglion receives the great splanchnic 

 nerve. The lower part of the ganglionic mass, lying over the root of the renal artery, 

 is commonly more or less detached from the rest, and is distinguished as the 

 aortico-renal ganglion ; it is joined by the small splanchnic nerve, and gives origin 

 to the greaterpart of the renal plexus. Another part, lying below and to the right 

 of the origin of the superior mesenteric artery, is named the superior mesenieric 

 ganglion. 



Diaphragmatic or phrenic plexus. The nerves 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 supra- 

 renal body, there is a small ganglion (diaphragmatic or phrenic ganglion), which 

 marks the junction 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. 



Suprarenal plexus. The suprarenal nerves issue from the solar plexus and 

 the outer part of the semilunar ganglion, some filaments being added from the 

 diaphragmatic plexus and one of the splanchnic nerves. They are short, but 

 numerous in comparison with the size of the suprarenal body, which they enter on 

 its inner and posterior part. These nerves consist in great part of white fibres, and 

 are beset with minute ganglia. 



Renal plexus. The nerves forming the renal plexus emanate for the most part 

 from the aortico-renal ganglion, but some are added from the solar and aortic 

 plexuses. The renal plexus also receives the termination of the smallest, and some- 

 times filaments from the small splanchnic nerve, as well as a branch from the first 

 lumbar ganglion. The nerves of the plexus are mostly grey, and in their course 

 along the renal artery ganglia of different sizes (renal ganglia) are formed on them. 

 Lastly, dividing with the branching of the vessel, the nerves follow the renal arteries 

 into the substance of the kidney. On the right side some filaments are furnished to 

 the vena cava, behind which the plexus passes with the renal artery ; and on both 

 sides offsets pass to the spermatic plexus, and a filament to the ureter. 



Spermatic plexus. This small plexus commences in the renal, but receives in 

 its course along the spermatic artery an accession from the aortic plexus, in which 

 a small spermatic ganglion is often formed at the place where these branches arise. 

 Continuing downwards to the testis, the spermatic nerves are connected with others 

 which accompany the vas deferens and its artery from the pelvis. 



In the female, the plexus, like the artery, is distributed to the ovary and the 

 uterus. 



