THE THORACIC CONTENTS 



507 



sac, which is termed the phrenico-costal sinus, the costal and 

 diaphragmatic pleurae are in immediate contact with one another 

 for a considerable distance during ordinary quiet inspiration. 



The costal pleura becomes continuous with the mediastinal 

 pleura not at one point only, as in Fig. 149, but along 



\ 



FIG. 150. Surface Relations of the Liver, Stomach, Lungs, Heart 



and Pleural Sacs. 



Blue line outline of lung. Dotted blue line = lines of pleural reflection. 

 Fine black line = heart and great vessels. Heavy black line = liver. Dotted 

 black line = stomach. 



a line termed the costo-mediastinal line of pleural reflection, 

 and similarly the costal pleura becomes continuous with the 

 diaphragmatic pleura along a line which is termed the costo- 

 diaphragmatic line of pleural reflection. These lines indicate the 

 limits of the pleural sacs and their relation to the surface of the 

 body is of great importance. 



Superiorly, the pleura bulges upwards for about one inch 



