136 HANDBOOK OF ANATOMY 



and is not quite so big as the entire cavity, the line of reflection 

 being 



Right pleura : Anterior, down the middle line of the sternum 

 to the back of the ensiform cartilage, along the seventh costal 

 cartilage, and across the bony extremities of the eighth and 

 ninth ribs. In the mid-axillary line the pleura reaches its- 

 lowest limit that of the bony tip of the tenth rib. It then 

 ascends slightly, cutting across the eleventh rib to the middle of 

 the twelfth rib and on to the first lumbar vertebra. The 

 posterior line of reflection is to the left of the mid-line of the 

 vertebral bodies, the aorta intervening between them. 



Left pleura : This only differs from the right in the anterior 

 line of reflection. Opposite the fourth costal cartilage the left 

 pleura deviates to the left, leaving a small area of pericardium 

 uncovered. It cuts 'across the fifth, sixth, and seventh costal 

 cartilages to the bony tip of the eighth rib, after which the line 

 of reflection resembles that of the right pleura. 



