CHAPTER IV 



The Thorax 



The Lungs aai Pleurae 



EXAMINATION. 



Examination of the lungs and pleurae is conducted by 

 means of auscultation and percussion. With the naked ear ap- 

 plied to the chest wall, respiratory sounds can be heard with 

 sufficient distinctness, but the employment of a stethoscope or phon- 

 endoscope accentuates them. Percussion is best accomplished by 

 tapping with the second finger of one hand on the corresponding 

 finger of the other hand laid flat against the chest wall. When 

 using these means for disgnostic purposes the position of neigh- 

 boring and more solid organs must always be taken into account. 



TRAXTMATIC LESIONS. 



Wounds of the lungs and pleurae occur for the most part as a 

 complication of penetrating wounds of the thoracic wall. Their 

 gravity depends upon the degree of resultant hemorrhage and 

 the entry of either atmospheric air or pyogenic bacteria within the 

 sacs. If air beyond a certain quantity enters a pleural sac, the 

 condition known as pneumothorax is established, and both lungs 

 collapse . The animal makes violent respiratory efforts which gradu- 

 ally become less frequent and finally cease, cyanosis meanwhile 

 developing. If, however, an open wound becomes quickly sealed, 

 either spontaneously or by surgical measures, the air is gradually 

 absorbed and the lung again takes on its function. This is also 

 true of hemorrhage exudates. Slight rents in the pleura are not 

 as a rule followed by entry of air. In rents or incisions of at 

 least a half to an inch in diameter the lung may be seen to glide 

 over the incision hole with each act of respiration, the cohesive 

 force of the two pleurae being sufficient to overcome the pressure 

 of the atmosphere through the incision. Delafond probed a wound 

 Il8 



