1238 



THE RESPIRATORY SYSTEM 



filling the lower part. The inferior margin of the lung enters this sinus a variable distance in 

 inspiration. The hne of the costo-diaphragmatic reflexion begins in front on the sixth costal 

 cartilage, which it follows, descending obliquely to cross the seventh interspace in the mam- 

 millary line. The greatest depth reached is at the tenth rib or interspace in the axillary line. 

 The line of reflexion then continues around the thorax ascending slightly to the twelfth costo- 

 vertebral joint. 



The hne of reflexion behind is sometimes found as low as the level of the transverse process 



Figs. 1001 and 1002. — Boundaries of the Pleur.e and Lungs. 



Lines of pleural reflection red, boundaries of the lungs and pulmonary lobes black. 



1, sixth cervical vertebra; 2, first thoracic vetebra; 3, twelfth thoracic vertebra; 4, first 

 lumbar vertebra; 5, manubrium sterni; 6, body of sternum; 7, xiphoid process; 8, first rib; 

 9, cartilage of seventh rib; 10, 11, 12, tenth, eleventh and twelfth ribs. (Rauber-Kopsch.) 



of the first lumbar vertebra. Such a possibility must be considered in operating upon the kidney. 

 The lines of reflexion of the costal pleura backward to the mediastinal pleura behind the 

 sternum begin opposite the sterno-clavicular joints, descend .obliquely medialward to the level 

 of the second costal cartilage, whence they run near together or in contact, but to the left of the 

 median hne, to the level of the fourth cartilage. The reflexion on the right side continues 

 from the sternum as far as the sixth rib cartilage, there turning laterally into the costo-dia- 

 phragmatic reflexion. The line on the left side, in the region of the cardiac notch (from the fourth 



Fig. 



1103. — Schematic Drawing to Represent the Maximum of Fluctuation in the 

 Position of the Anterior Lines of Pleural Reflexion. (Tanja.) 



to the sixth cartilages), is a little to tlio left of the sternal margin. From tliis position of the 

 line of reflexion it happens tliat then; is left uncovered })y pleura a small area of the pericardium 

 which is in contact inimodiatcly with tiu! chest-wall. A reduplication of the pleura takes 

 place along the anterior line of reflexion, and into the sinus costomediastinalis so formed the 

 thin anterior margin of the lung advances in inspiration. That part of the left costo-niediastinal 

 sinus which is in front of the pericardium is not comi)let(dy fllled by the margin of the lung. 

 Although the jjositions of the lines of reflexion of the mediastinal j)leiira here described are those 



