352 THE RESPIRATORY SYSTEM 



greater frequency of tuberculous disease in the right apex, the 

 sign is more frequently present on the right side. 



Lombardi claims that this "varicose zone of alarm" is 

 present in nearly 90 per cent, of cases of primary tuberculosis 

 of the apex. 



The antero-inferior group of the deep cervical lymph glands 

 lie in relation to the medial border of the scalenus anterior, and 

 some members of the group are in contact with the cupula 

 pleurae. These glands receive their afferents from the tonsillar 

 lymph gland, amongst others, and they are, on that account, 

 frequently the site of tuberculous infection. In order to 

 account for the frequency of apical phthisis, the theory has 

 been put forward that the lung apex is infected from the deep 

 cervical lymph glands through the pleura, which first becomes 

 thickened and adherent. 



The relationship which the clavicle bears to the apex of the 

 lung is important, because it indicates that percussion over the 

 clavicle is of little value unless precisely similar points are 

 chosen on the two sides, when comparisons are being made. 

 The medial inch and a half of the clavicle lies directly in front 

 of the apex, from which it is separated only by the sterno-hyoid 

 muscle and the innominate vein. Percussion over this part of 

 the bone gives a resonant note, but its character is affected by 

 the damping influence of the " plectrum." Immediately lateral 

 to this portion, the clavicle is separated from the lung by the 

 first rib, and the percussion note consequently alters in character. 

 Beyond the first rib, the clavicle forms the anterior boundary 

 of the apex of the axilla, but a resonant note is obtained on 

 percussion, as the "plectrum" is no longer placed on the 

 sternal extremity, which is therefore able to vibrate freely. 



The Base of the Right Lung is deeply hollowed out to 

 accommodate itself to the right cupola of the diaphragm, which 

 is thrust upwards by the large right lobe of the liver. The 

 margins of the base form the thin lower border of the lung, 

 and, in order to determine the precise downward extent of the 

 right lung, very light percussion must be used. 



