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THORACIC AORTA ABDOMINAL AORTA. 



column, but approaches the middle line as it descends, and at the 

 aortic opening of the diaphragm is altogether in front of the column. 

 After entering the abdomen it again falls back to the left side. 



Relations. It is in relation, behind with the vertebral column 

 and lesser vena azygos ; in front with the esophagus and right 

 pneumogastric nerve ; to the left side with the pleura ; and to the 

 right with the thoracic duct. 



Plan of the relations of the thoracic Aorta. 



In Front. 

 (Esophagus, 

 Right pneumogastric nerve. 



Right Side. 

 Thoracic duct. 



Thoracic Aorta. 



Left Side. 

 Pleura. 



Behind. 



Lesser vena azygos, 

 Vertebral column. 



The abdominal aorta enters the abdomen through the aortic open- 

 ing of the diaphragm, and descends, lying rather to the left side of 

 the vertebral column, to the fourth lumbar vertebra, where it divides 

 into the two common iliac arteries. 



Relations. It is crossed, in front by the left renal vein, pancreas, 

 transverse duodenum, and mesentery, and is embraced by the aortic 

 plexus ; behind it is in relation with the thoracic duct, receptaculum 

 chyli, and left lumbar veins. 



On its left side is the left semilunar ganglion and sympathetic 

 nerve; and on the right the vena cava, right semilunar ganglion, 

 and the commencement of the vena azygos. 



Plan of the relations of the abdominal Aorta. 



Right Side. 



Vena cava, 



Right semilunar ganglion, 



Vena azygos. 



In Front. 

 Left renal vein, 

 Pancreas, 



Transverse duodenum, 

 Mesentery, 

 Aortic plexus. 



Abdominal Aorta. 



Behind. 

 Thoracic duct, 

 Receptaculum chyli, 

 Left lumbar veins. 



LeftSide. 



Left semilunar gan- 

 glion. 

 Sympathetic nerve. 



