THE HEAET AND GEEAT VESSELS. 1403 



The roots of the lungs are situated opposite the fourth, fifth, and sixth thoracic 

 spines, midway between them and the vertebral margins of the scapulae. 



Crus of diaphragm . Cms of diaphragm 



Lateral lumbo-costal 

 arch 



Lateral lumbo-costal 

 Diaphragm / JE^P^ JUKI mHk A ~K \ \ 



hragm 



\i^ LIVM 



Intestine 



* Ascending colon 



FIG. 1095. DISSECTION FROM BEHIND TO SHOW THE RELATION OF THE TWO PLEURAL SACS TO THE KIDNEYS. 

 Outlines of superior portions of the two kidneys are indicated by dotted lines. (From Cunningham.) 



The lower end of the trachea, the bronchi, the vagi, and the left recurrent nerve, are all 

 more or less surrounded by lymph glands, which, when enlarged, may exert injurious pressure 

 upon them. 



THE HEART AND GREAT VESSELS. 



Viewed from the front, the outline of the precordial area, like that of the peri- 

 cardial sac, is roughly triangular, the base of the triangle being below and the apex 

 above. The boundaries are delineated upon the surface as follows : 



The right side of the triangle, formed by the right atrium, is indicated by 

 drawing a line slightly convex laterally from the superior end of the third to the 

 sixth costal cartilage, a finger's breadth from the edge of the sternum ; the curve 

 attains its maximum opposite the fourth intercostal space, where it reaches one 

 land a half inch from the median plane. 



The base of the triangle, formed by the mar go acutus of the right ventricle and 

 to a very slight extent by the apical portion of the left ventricle, is almost 

 ; horizontal, and corresponds to a line drawn from the inferior extremity of the right 

 side of the triangle to the apex of the left ventricle, which lies behind the fifth left 

 intercostal space, three and a half inches from the median plane, and half an inch 

 medial to the mid-clavicular line. The base line crosses the xiphoid process 

 jit its junction with the body of the sternum. 



The left side of the triangle, formed by the margo oltusus of the left ventricle, is 

 .indicated by a slightly curved line extending from the apex of the heart upwards 

 to the inferior edge of the second interspace, a finger's breadth from the sternum, the 

 tSonvexity of the curve being directed laterally and slightly upwards. 



The truncated apex of the triangle, which lies behind the sternum at the level 

 pf the second intercostal space, corresponds to the highest part of the heart, 

 namely, where the auricles of the atria embrace the aorta and pulmonary artery. 



The situation of the anterior part of the coronary sulcus is mapped out by a 

 line drawn from the median plane, opposite the inferior border of the third left 

 postal cartilage, downwards and laterally to the sixth right chondro - sternal 

 [unction ; the line should be slightly convex upwards and to the right. The right 

 luricle lies at, or a little to the right of, the median plane, at the level of the second 



