THE ABDOMEN, INTERIOR. 509 



The Cceliac Axis. Figs. 104, 105, 106. 



This is the second branch of the abdominal aorta. It is 

 a large trunk coming off the front of the abdominal aorta 

 just after it comes through the diaphragm. 



The Solar Plexus. Figs. 74, 106, 107. 



About the cceliac axis will be found the semilunar gang- 

 lia, the right and left, joined together by numerous nerve 

 filaments composing the solar plexus (abdominal brain). 

 From the solar plexus nerves pass to the various abdom- 

 inal organs with the blood vessels. They form secondary 

 plexuses upon, and take the names of, the arteries they 

 accompany. 



The Semilunar Ganglia. Figs. 74, 107. 



Are irregularly shaped masses, one on either side of the 

 cceliac axis and superior mesenteric arteries. 



The greater and lesser splanchnic nerves are formed 

 within the thorax (see page 345) ; after piercing the crus of 

 the diaphragm they enter the upper part of the semilunar 

 ganglion to take part in the formation of the solar plexus. 



Branches of Cceliac Axis. The cceliac axis divides into 

 the gastric, hepatic, and splenic arteries. 



The Gastric Artery. Figs. 104, 105. 



This is the smallest of the three branches. It passes 

 upward to the left to reach the stomach at the junction of 

 the oesophagus, then turns downward, following the lesser 

 curvature, until it anastomoses with the pyloric. Its 

 branches are () cesophageal, running upward to the oeso- 

 phagus, to anastomose with the thoracic cesophageal, (b) 

 the branches over the fundus, to unite with splenic branches, 

 (c) terminal, anastomosing with the pyloric. 



