THE ABDOMEN 739 



situated in front of the body of the fifth lumbar vertebra between 

 the common iliac vessels. It is a large fiat plexus, measuring 

 about ih inches in breadth, and it ends in two divisions, which 

 become the right and left pelvic plexuses. 



Coeliac Axis. — ^The coeliac axis is a short thick trunk which arises 

 from the front of the aorta between the crxua of the diaphragm 

 just below the aortic opening. Its direction is straight forwards 

 over the superior border of the body of the pancreas, and, after a 

 course of about \ inch, it divides into three radiating branches — 

 gastric, splenic, and hepatic. Of these the splenic is the largest, 

 except during foetal life when it is exceeded by the hepatic. The 

 branches of the axis supply the stomach, duodenum, pancreas, 

 spleen, liver, and gall-bladder. 



Relations. — ^The right lobe of the liver above, the superior 

 border of the body of the pancreas below, the gastro-hepatic omen- 

 tum in front, and a semilunar ganglion on either side, with the 

 Spigelian lobe of the liver as an additional right relation. The 

 axis is closely surrounded by the coeliac sympathetic plexus. 



The gastric (coronary) artery is directed upwards and to the 

 left as far as the small ciirvature of the stomach on the right 

 side of the oesophagus. It then bends sharply forwards and 

 downwards, and descends in two divisions from left to right along 

 the small curvature towards the pylorus, where it anastomoses 

 with the two divisions of the pyloric branch of the hepatic. 

 The artery is at first behind the small sac of the peritoneum, 

 but along the small curvature it lies between the two layers of 

 the gastro-hepatic omentum, and is surrounded by the gastric 

 sympathetic plexus. 



Branches. — ^These are oesophageal, cardiac, and gastric. The 

 oesophageal branches arise when the artery reaches the small curva- 

 ture, and they ascend through the oesophageal opening of the 

 diaphragm to anastomose on the gullet with the lower oesophageal 

 branches of the thoracic aorta. The cardiac branches are distributed 

 to the cardiac end of the stomach, where they anastomose with 

 the vasa brevia of the splenic. The gastric branches arise from the 

 two divisions of the artery on the small curvature, and pass to the 

 front and back of the stomach, where they anastomose with branches 

 of the gastro-epiploic arteries. 



" The gastric vein ascends from right to left along the small 

 curvature of the stomach as far as the oesophagus, where it receives 

 a few oesophageal tributaries, after which it turns to the right and 

 opens into the vena portae. 



The splenic artery takes a tortuous course to the left along the 

 superior border of the body of the pancreas behind the small sac. 

 On reaching the front of the left kidney it breaks up into several 

 splenic branches which enter the spleen through the hilum. The 

 artery is invested by the splenic sympathetic plexus, and the splenic 

 vein hes below it, and behind the pancreas. 



Branches. — These are pancreatic, left gastro-epiploic, vasa brevia, 



