THE ORGANS OF RESPIRATION 



241 



second piece of the sternum. At the root of the lung 

 the visceral and parietal layer of the same side are 

 continuous, and at the lower part of the root a fold, 

 the ligamentum latum pulmonis, runs down to the 

 diaphragm. 



FIG. 92 



Left Phrenic Nerve 



Pleura Pulmonahz. 

 cvra Costalis. 



Sympathetic JVi . . 



Thoracic Duct. 



Vena Azygos Majc 

 Vagus Nerrves 



A transverse section of the thorax, showing the relative positions of the 

 viscera and the reflections of the pleurae. (Gray.) 



The Lungs (Pulmones). The lungs are the essential 

 organs of respiration; they are situated in the right 

 and left sides of the thorax, covered by the visceral 

 portion of the pleura; filling the cavity, with the 

 exception of the intervening mediastinum. The 

 latter is a space within the thorax situated between 

 the right and left lobes of the lungs; it contains the 

 heart covered by the pericardium, the great vessels 

 of the heart, the esophagus, trachea, bronchi, thymus 

 gland, thoracic ducts, nerves to the heart, lungs, and 

 other organs. It is divided into superior, anterior, 

 16 



