444 



DISSECTION OF THE THORAX. 



behind they come nearer together. The partition is artificially 

 divided into four parts, which are distinguished as the superior, 

 anterior, middle, and posterior mediastina. 



Groove formed by 

 subclavian artery. 



Superior inter- 

 costal vein. 

 > Left innominate 



vein. 



Groove formed 

 by left innomi- 

 nate vein. 



Superior 

 medias- 

 tinum : 

 boundaries, 



Right coronary artery. 



FIG. 161. THE CONTENTS OF THE THORAX SEEN FROM THE FRONT. THE 

 LUNGS WERE FILLED WITH MELTED WAX AND WERE HELD APART IN 

 FRONT UNTIL THE WAX HAD SET. (FROM A SPECIMEN IN CHARING 

 CROSS HOSPITAL MUSEUM.) 



The superior mediastinum is the part of the thoracic chamber 

 above the pericardium, and may be denned a.s bounded below 



