TOPOGRAPHY OF THE THORAX AND ABDOMEN 15 



THE LUNGS 



The lungs appear in Plates V to XIII and XXVIII to 

 XXXV. While the left lung is adherent to the pleural wall 

 throughout, its substance seems to be perfectly normal. The 

 apex of the right lung is about 2 cm. and that of the left 

 lung about 3.5 cm. above the upper border of the middle of 

 the inner third of the clavicle, on a level with the middle of 

 the first thoracic vertebra 3.5 cm. from the midline. By 

 projecting up into the neck each apex comes into relations 

 with the structures above the clavicle. The eighth cervical 

 nerve and the lower trunk of the brachial plexus cross it 

 from above outward and forward, while the sympathetic 

 cord and inferior cervical ganglion rest upon it internally. 

 The vertebral and ascending cervical vessels lie upon the 

 anterior part of the pleural dome in their passage upward 

 into the neck. The arch of the thoracic duct is separated 

 from the left apex by these vessels (Plate IV). The sub- 

 clavian artery arches across the apex less than 1 cm. from 

 its highest point and separates the lung from the scalenus 

 anterior muscle and the internal jugular vein. The innom- 

 inate vein lies just below the subclavian artery and separates 

 the lung and sternoclavicular articulation. When seen in 

 anterior projection the apex of each lung is overlapped by 

 the lower part of the corresponding lateral lobe of the thy- 

 reoid gland (Plates XXVIII and XXXII). The two organs 

 are not in contact however (Plates XXX, XXXI, 

 XXXIV and XXXV). The apex of the lung comes nearly 

 to the surface of section IV in the quadrilateral space in 

 front of the neck of the first rib where it is 6 or 7 cm. from 

 the anterior surface of the neck and where it is separated 

 from the thyreoid gland by the vertebral and ascending cer- 

 vical vessels, and the internal part of the carotid sheath 



