1192 



THE ORGANS OF VOICE AND RESPIRATION 



furrow for the innominate artery. Along the back part of the inner surface 

 is a vertical groove for the oesophagus; this groove becomes less distinct below, 

 owing to the inclination of the lower part of the oesophagus to the left of the middle 

 line. In front and to the right of the lower part of the oesophageal groove, the 

 inner surface is applied to the pleural covering of the right and posterior aspects 

 of the thoracic parts of the inferior vena cava; this vessel being accommodated 

 in a deep concavity. 



On the left lung (Fig. 904), immediately above the hilum, is a well-marked 

 curved furrow produced by the arch of the aorta, and running upward from this 

 toward the apex is a groove accommodating the subclavian artery; a slight impres- 

 sion in front of the latter and close to the margin of the lung lodges the left in- 

 nominate vein. Behind the hilum and pericardial depression is a vertical furrow 

 produced by the descending thoracic aorta, and in front of this, near the base 

 of the lung, the lower part of the oesophagus causes a shallow depression. 



FIG. 905. Front view of the heart and lungs. 



Borders. The posterior border (margo posterior) is broad and rounded, and 

 is received into the deep concavity on either side of the vertebral column. It is 

 much longer than the anterior border. 



The inferior border (margo inferior} is the margin of the base separating the 

 costal and diaphragmatic surfaces. It projects, below, into the upper part of 

 the costophrenic sinus. 



The anterior border (margo anterior) is thin and sharp, overlaps the front of the 

 pericardium, and is projected into the costomediastinal sinus of the pleura. The 

 anterior border of the right lung is almost vertical; that of the left presents, below, 

 an angular notch, the incisura cardiaca, into which the heart and pericardium are 



