1184 



THE ORGANS OF VOICE AND RESPIRA TION 



sac, one occupying the right, the other the left half of the thorax, and they do not 

 communicate with each other. The two pleurae do not meet in the middle line 



TRIANGULARIS STERN1 



Internal Mammary Vessels. 



Left Phrenic Ner 



Pleura Pulmonaiis. 

 Pleura Costalis. 



Sympathetic Nerve. 



Thoracic Duct. 



Vena Azygos Major. 

 ^Vagus Nerves. 



FIG. 897. A transverse section of the thorax, showing the relative position of the viscera and the 



reflections of the pleurae. 



of the chest, excepting anteriorly opposite the second and third pieces of the ster- 

 num. The space left between them contains all the thoracic viscera excepting 

 the lungs, and is named the mediastinum. 



SCALENUS 

 MINIMUS 



SYMPATHETIC 

 GANGLION 



FIG. 898. The dome of the pleura. (Poirier and Charpy.) 



Different portions of the parietal pleura have received special names which 

 indicate their position; thus, that portion which lines the inner surfaces of the ribs 



