138 HANDBOOK OF ANATOMY 



Upper line a line slightly convex downwards connecting the 

 upper extremities of the right and left sides. 



The Base of the Heart is formed by the auricles, and is 

 directed upwards, backwards, and to the right. It lies opposite 

 the sixth, seventh, and eighth dorsal vertebrae, separated from 

 them by the oesophagus and descending aorta. It has six 

 orifices the superior and inferior venae cavas entering the 



Superior Vena Cava t*^f*9f^S 



^.Aorta 



Right Auricular Appendix 



Right Auricle ^ 



, Pulmonary Artery 

 ,Conus Arteriosus 



Right Coronary Artery 



. Left Ventricle 



- Left Coronary Artery 



Apex 



FIG. 54. THE HEART. 



right auricle, and the four pulmonary veins entering the left 

 auricle. 



The Apex of the Heart is formed entirely by the left ven- 

 tricle. It is directed downwards, forwards, and to the left, and 

 is separated from the anterior thoracic wall by the left lung 

 and pleura. 



The Inferior Surface is formed by the ventricular portion of 

 the heart, and rests upon the central tendon of the diaphragm 

 and the muscular part to the left of the tendon. 



The Antero- Superior Surface is directed backwards, upwards, 

 -and to the left. It lies behind the area of the anterior thoracic 



