948 



A MANUAL OF ANATOMY 



The greater part of it is concave in adaptation to the heart, enclosed 

 in the pericardium, the concavity being greater m the case of the 

 left lung on account of the projection of the heart to the left 

 side. About the junction of the anterior two-thirds and posterior 

 third this surface presents a vertical fissure, called the hilum pul- 

 monis, at which the root of the lung is situated. The inner surface 

 of the right lung, behind the hilum, is related to the oesophagus, 

 and the corresponding portion of the inner surface of the left lung 

 presents part of the aortic groove, vertically placed and produced 

 by the descending thoracic aorta. Anterior to the lower part of 

 this groove the left lung is related to the oesophagus, but less 



Fig. 387. — Diagram showing the Heart and Lungs in Situ. 



1. Tricuspid Orifice 3. Mitral Orifice 



2. Pulmonary Orifice. 4. Aortic Orifice 



X, Region of Latham's Circle 



intimately than the right lung. The inner surface of the right 

 lung presents the following grooves above the level of the hilum, 

 named in order from below upwards : (i) azygos, for the right 

 azygos vein ; (2) caval and innominate, for the superior vena cava 

 and right innominate vein ; and (3) arterial, for the innominate 

 artery. The inner surface of the left lung presents the following 

 grooves above the level of the hilum : (i) the commencement of 

 the aortic groove, transversely disposed, for the arch of the aorta ; 

 (2) the subclavian groove, for the left subclavian artery, leading 

 upwards from the preceding ; and (3) an indefinite groove, anterior 

 to the subclavian groove, for the left innominate vein. 



The borders are anterior and posterior. The anterior border is 

 thin and short, and overlaps the jxjricardium, more .so during 



