THE THORAX. 115 



the left being in front. On either side of the attach- 

 ment to the xiphoid cartilage is a space where the mus- 

 cular tissue is wanting, so that between the abdominal 

 cavity and that of the anterior mediastinum there is a 

 communication, filled in by a little cellular tissue, 

 through which pass some lymphatics from the liver, 

 and occasionally diaphragmatic hernia. Collections of 

 pus forming in the thoracic cavity may find their way 

 through these spaces ; moreover, as the diaphragm sepa- 

 rates the right lung from the liver, abscesses forming in 

 this latter viscus may either be discharged by the bron- 

 chi or into the thoracic cavity. 



Penetrating wounds of the diaphragm are serious, 

 partly on account of hemorrhage, and from the fact of 

 viscera, both of the thoracic and abdominal cavities, 

 being implicated ; and partly on account of the intimate 

 connection with it of large serous cavities, the pleurae, 

 the peritoneum, and the pericardium. 



Occasionally paralysis of the diaphragm occurs with 

 ascites, or may be owing to a wound in the neck or spi- 

 nal column, implicating the phrenic nerve. 



An approximation of the course taken by a bullet or 

 a weapon penetrating the walls of the thorax from its 

 anterior or lateral aspects, may be gathered from the 

 following facts : That the heart would be reached by a 

 wound traversing the chest at right angles, above the 

 sixth rib, and that its apex lies about an inch and a 

 half from the surface. Wounds in the mesial line 

 would involve the heart and great vessels, whilst more 

 laterally they would implicate the lungs; the position 

 of the trunk and branches of the internal mammary 

 render penetrating wounds of the inferior intercostal 

 spaces near the sternum very serious. 



