102 TOPOGRAPHIC AND APPLIED ANATOMY. 



FIG. 47. The median surface of the right lung. From plaster cast (His). 

 FIG. 48. The median surface of the left lung. From plaster cast (His). 



tion of inflammatory exudates is made possible by the great number of lymphatic vessels in the 

 pleura. The remains of such exudates are frequently found at postmortems as opacities and 

 thickenings of the pleura as well as in the form of cicatricial and firm adhesions between the 

 parietal pleura and the surface of the lung. In such cases the lung is said to be adherent. 



The topographic relations of the pleural cavities and of the lungs to the abdominal organs 

 situated immediately beneath the diaphragm are of great importance. These relations are 

 described upon pages 128-133, 138, and 139. 



The Lungs. The apex of the lung fills the dome of the pleura and consequently extends 

 above the superior aperture of the thorax (Fig. 45, Plates n and 13); the concave base rests 

 upon the diaphragm. The costal surface of the lung lies against the inner surfaces of the ribs 

 and of the intercostal spaces (i. e., against the costal pleura) ; the diaphragmatic surface or base 

 is in contact with the diaphragmatic pleura. The third or mediastinal surface forms the boun- 

 dary of the mediastinum and is hollowed out to accommodate the heart. The anterior sharp 

 margin is lodged in the costo-mediastinal sinus ; the inferior margin, which is also sharp, is directed 

 toward the costo-phrenic sinus. The posterior convex margin is surrounded in the region of the 

 angles of the ribs by the pulmonary sulci of the thorax (Figs. 50 and 53). At the root of the lung 

 (hilus pulmonis) upon the mediastinal surface, the arteries of the bronchi enter, and the veins 

 leave the viscus (Figs. 47 and 48). 



Each lung is divided into two lobes by a deep fissure (incisura interlobaris) which pursues 

 an almost symmetrical course upon the two sides. It passes upward and backward from the 

 hilus, runs forward over the costal surface to the lower pulmonary margin, crosses the base 

 anteriorly, and ascends to the hilus along the mediastinal surface. In the left lung this fissure 

 separates the upper from the lower lobe. In the right lung the fissure runs more directly down- 

 ward than upon the left side. While the fissure strikes the lower margin of the left lung about 

 a fingerbreadth to the outer side of its anterior extremity, it reaches the lower margin of the right 

 lung about a handbreadth to the outer side of the corresponding point. In the right lung there 

 is a second fissure, wilich runs from the hilus over the mediastinal surface, crosses the anterior 

 border of the lung, and passes horizontally along the costal surface to join the incisura inter- 

 lobaris. It forms the upper boundary of the small middle lobe, which is present only upon the 

 right side and varies greatly in its development. In the anterior border of the left lung there 

 is a notch (incisura cardiaca) the concavity of which is directed toward the median line. In the 

 hilus the branches of the pulmonary artery are the highest structures; below these are the bronchi, 

 with the exception of the eparterial bronchus to the right superior lobe, which is situated higher 

 up. The veins are partly below and partly in front of the bronchi (Figs. 47 and 48). 



If the lungs are hardened in situ and the neighboring vessels are well injected, the follow- 

 ing grooves may also be noted : the grooves for the superior vena cava and for the vena azygos 

 major upon the right lung; the grooves for the left subclavian artery, for the arch of the aorta, 

 and for the descending aorta upon the left lung. 



The respiratory changes in the position of the lung are most distinctly manifested at the 



