352 A MANUAL OF ANATOMY. 



left of the middle plane of the body. The oesophagus with 

 the pneumogastric nerves pass through it. Also some 

 small cesophageal arterial filaments. 



The caval opening is in the right portion of the diaphragm 

 at the posterior border of the central tendon where the 

 right and middle leaflets join. Through it passes the inferior 

 vena cava. 



Through the crura pass the cord of the sympathetic 

 nerve, the splanchnic nerves, and in addition, on the left 

 side, the azygos minor vein. 



Having removed the heart and great vessels (viz. : the 

 ascending and transverse aorta and its branches, the pul- 

 monary artery, the superior cava), the trachea and lungs, in 

 one mass, they are to be dissected : 



(i) The heart, great vessels, coronary arteries, ventricles, 

 and auricles are to be studied as they are seen from the 

 front. (2) The structures and their relations which com- 

 pose the root of the lungs are to be investigated. (3) Sep- 

 arate the heart (and vessels) from the lungs (and trachea). 

 (4) Complete the dissection of the posterior of the heart 

 (ventricles, auricles, and vessels), then open its cavities and 

 learn their parts or contents. (5) Complete the study and 

 comparison of the right and left lung, inflating them for 

 this purpose. (6) Follow up the bronchi to the main sub- 

 divisions, three for the left and two for the right lung. 



The Right Coronary Artery. Figs. 70, 71. 



Comes off from the anterior sinus of Valsalva of the 

 aorta, appears between the right auricle and pulmonary 

 artery, follows the auriculoventricular groove to the right 

 border of the heart, here divides into two terminal arteries. 

 One continues the course around in the auriculoventri- 

 cular groove to the back of the heart to anastomose with a 



