ARCH OF THE AORTA. 279 



Relations. The ascending aorta has in relation with it, in front, the 

 trunk of the pulmonary artery, thoracic fascia, -and pericardium; behind, 

 the right pulmonary veins and artery ; to the right side, the right auricle 

 and superior cava ; and to the left, the left auricle and the trunk of the 

 pulmonary artery. 



Plan of the Relations of the Ascending Aorta. 



In Front. 



Pericardium, 



Thoracic fascia, 

 Pulmonary artery. 



Right Side. 



Superior cava, 

 Right auricle. 



Ascending Aorta. 



Left Side. 



Pulmonary artery. 

 Left auricle. 



Behind. 



Right pulmonary artery, 

 Right pulmonary veins. 



Arch. The upper border of the arch of the aorta is parallel with tta 

 upper border of the second sterno-costal articulation of the right side iii 

 front, and the second dorsal vertebra behind, and terminates opposite the 

 lower border of the third. 



The anterior surface of the arch is crossed by the left pneumogastric 

 nerve, and by the cardiac branches of that nerve and of the sympathetic. 

 The posterior surface of the arch is in relation with the bifurcation of the 

 trachea and great cardiac plexus, the cardiac nerves, left recurrent nerve, 

 and the thoracic duct. The superior border gives off the three great arte- 

 ries, viz. the innominata, left carotid, and left subclavian. The inferior 

 border, or concavity of the arch, is in relation with the remains of the 

 ductus arteriosus, the cardiac ganglion and left recurrent nerve, and has 

 passing beneath it the right pulmonary artery and left bronchus. 



Plan of the Relations of the Arch of the Aorta. 



Jtbove. 



Arteria innominata, 

 Left carotid, 

 Left subclavian. 



In Front. Behind. 



Bifurcation of the trachea, 



Left pneumogastric 



nerve, 

 Cardiac nerves. 



Arch of the Aorta. 



Great cardiac plexus, 

 Cardiac nerves, 

 Left recurrent nerve, 

 Thoracic duct. 



Below. 



Cardiac ganglion, 

 Remains of ductus arteriosus, 

 Left recurrent nerve, 

 Riht pulmonary artery, 

 Left bronchus. 



The descending aorta is subdivided in correspondence with the two 

 great cavities of the trunk, into the thoracic and abdominal aorta. 



