538 SPLANCHNIC NERVES. SEMILUNAR GANGLION. 



sides of the bodies of the vertebrae, and unite into one trunk 

 that is denominated the Splanchnic Nerve, because it is distri- 

 buted to the viscera of the abdomen. This nerve proceeds be- 

 hind the crus of the diaphragm, on its respective side, into the 

 abdomen. A second and smaller nerve, of the same destina- 

 tion, called the lesser Splanchnic Nerve, arises lower down, from 

 two or three of the lowermost dorsal ganglions, and penetrates 

 separately into the cavity of the abdomen : it then generally 

 divides into two branches, one of which unites to the great 

 splanchnic nerve, and the other proceeds to the renal plexus 

 soon to be described. 



As soon as the great splanchnic nerve has entered the abdo- 

 men, it divides into many branches, which commonly form small 

 ganglions on each side of the coeliac artery, but above it. These 

 ganglions are generally contiguous : but sometimes they are at 

 a small distance from each other, and united by nerves. They 

 are, however, commonly spoken of as one, and called the Semi- 

 lunar Ganglion. They are of irregular forms, and very different 

 from each other in size, as well as form. Those formed by the 

 splanchnic nerve on one side are sometimes different from those 

 on the other. 



From this assemblage of ganglions proceed many small nerves, 

 which are woven together so as to form a network denominated 

 the Solar Plexus. 



This plexus is situated anterior to the spine and the crura of 

 the diaphragm, behind the stomach and above the pancreas ; 

 and is extended upon the coeliac and superior mesenteric arte- 

 ries. Some ramifications from the par vagum and the phrenic 

 also join it. 



The lower part of the solar plexus, which surrounds more 

 immediately the coeliac artery, is termed the Cceliac Plexus. 

 From it networks of nerves extend upon the great branches of 

 the artery to the organs to which they go. 



They extend to the stomach, (although it is supplied by the 

 par vagum,) along the superior coronary or gastric branch of 

 the coeliac ; and the fibres in their composition being spread 



