410 SPLANCHNOLOGY, OR ANATOMY OF THE VISCERA 



impression is seen for the esophagus along the posterior part 

 of the internal surface. 



Borders. The posterior border (margoposterior) is convex 

 and broad, and much longer than the anterior border, and 

 fits into the deep grooves on either side of the spinal column. 

 The inferior border (margoinferior) is sharp and separates 

 the costal and diaphragmatic surfaces. It extends behind 

 into the costophrenic sinus of the pleura. 



The anterior border is thin and sharp, overlaps the peri- 

 cardium and extends in front into the costomediastinal sinus 

 of the pleura. The anterior border of the right lung is almost 

 vertical; that of the left shows, at the anterior part of the 

 cardiac depression, an angular notch, the incisura cardiaca, 

 into which the left ventricle of the heart, covered by the peri- 

 cardium is received. Just below this notch a projection of 

 the upper lobe of the lung comes forward overlying the apex 

 of the heart; it is called the lingula pulmonis. 



Fissures and Lobes. The left lung is divided into two lobes, 

 an upper and a lower, by an oblique fissure, which extends 

 from the outer to the inner surface of the lung both above 

 and below the hilum. The right lung is divided into three 

 lobes, an upper, middle, and lower, by an oblique fissure, 

 separating the lower and middle lobes, a horizontal fissure 

 separating the upper and middle lobes. The oblique fissure 

 corresponds to the left fissure with the exception that it cuts 

 the inferior border of the lung three inches behind its anterior 

 inferior angle, whereas the left cuts the border an inch behind 

 its extremity. The horizontal fissures cuts the anterior border 

 of the lung at the level of the sternal end of the fourth costal 

 cartilage, on the inner surface, and extends backward to the 

 hilum of the lung. 



The right lung is heavier and larger, also shorter and not 

 so broad as the left. 



The Root of the Lung (Radix Pulmonis) lies a little above the 

 centre of the mediastinal surface, and approaches nearer to the 

 posterior than its anterior border. It transmits the bronchus, 

 the pulmonary artery, the two pulmonary veins, usually, the 

 bronchial arteries and veins the former supply the bronchi and 

 lungs with blood the pulmonary plexus of nerv'es, lymphatics, 

 the bronchial lymph nodes, and areolar tissue, surrounded 

 by a reflection of the pleura which fuses with the pericardium 



