THE LUNGS 



1095 





The mediastinal surface (fades mediastinalis; inner surface) is in contact with 

 the mediastinal pleura. It presents a deep concavity, the cardiac impression, 

 which accommodates the pericardium; this is larger and deeper on the left than 

 on the right lung, on account of the heart projecting farther to the left than to the 

 right side of the median plane. Above and behind this concavity is a triangular 

 depression named the hilum, where the structures which form the root of the lung 

 enter and leave the viscus. These structures are invested by pleura, which, below 

 the hilus and behind the pericardial impression, forms the pulmonary ligament. 

 On the right lung (Fig. 972), immediately above the hilus, is an arched furrow 

 which accommodates the azygos vein; while running upward, and then arching 

 lateralward some little distance below the apex, is a wide groove for the superior 

 vena cava and right innominate vein; behind this, and nearer the apex, is a furrow 



Groove for 

 innominate artery 



Groove for 

 sup. vena cava 



Pulmonary 

 artery 



Groove, for azygos 

 vein 



Eparterial 

 bronchus 



Hyparterial 



bronchus 



Pulmonary 



veins 



Groove for 

 esophagus 





FIG. 972. Mediastinal surface of right lung. 



for the innominate artery. Behind the hilus and the attachment of the pulmonary 

 ligament is a vertical groove for the esophagus; this groove becomes less distinct 

 below, owing to the inclination of the lower part of the esophagus to the left of 

 the middle line. In front and to the right of the lower part of the esophageal 

 groove is a deep concavity for the extrapericardiac portion of the thoracic part 

 of the inferior vena cava. On the left lung (Fig. 973), immediately above the hilus, 

 is a well-marked curved furrow produced by the aortic arch, and running upward 

 from this toward the apex is a groove accommodating the left subclavian artery; 

 a slight impression in front of the latter and close to the margin of the lung lodges 

 the left innominate vein. Behind the hilus and pulmonary ligament is a vertical 

 furrow produced by the descending aorta, and in front of this, near the base of 

 the lung, the lower part of the esophagus causes a shallow impression. 



