PHTHISIS. 317 



spine, but since this is opposite the disc between the third and 

 fourth dorsal vertebrae, the tracheal bifurcation is really lower 

 down. The bifurcation is one vertebra higher in the infant than 

 in the adult, but, nevertheless, it corresponds to the third costal 

 cartilage in front instead of to the second, owing to the less 

 obliquity of the ribs. The marked deviation of the lower end of 

 the trachea to the right is due to the pressure exerted upon it by 

 the aortic arch, and this leaves a distinct impress on the side of 

 the air tube. In children a " cracked-pot " sound may often be 

 obtained below the clavicle, especially on the right side ; the 

 thinness and flexibility of the chest wall and the proximity of 

 the trachea and bronchi account for this phenomenon, the air 

 being easily driven out by forcible percussion. 



A systolic murmur can often be heard in the subclavian arteries 

 of those who suffer from phthisis. In some cases, no doubt, this 

 is hsemic, but the artery is in close relation to the pleural dome, 

 which it actually indents, and so may be compressed by pleural 

 adhesions or by a solid portion of the lung. The inflammatory 

 thickening of the apical pleura may also entangle and paralyse 

 certain nerves which lie adjacent to it. The recurrent laryngeal 

 nerves, particularly that of the right side, the phrenics and the 

 dorsal sympathetic fibres to the eye, are all liable to implication 

 in this way. Unilateral abductor laryngeal paralysis, unilateral 

 paralysis of the diaphragm or unilateral ptosis, myosis and 

 enophthalmos may thus be produced. 



When there is much fibrous contraction of the lungs, the heart 

 comes more fully into contact with the chest-wall, and the area 

 of visible pulsation is increased. Under these circumstances the 

 conus arteriosus may beat in the second left interspace, being 

 drawn upwards as well as uncovered. The shock of pulmonary 

 valve closure can often be actually felt in this situation. On 

 auscultation the loudness of the second sound will be evident. 

 Contraction of the left lung allows the area of gastric resonance 

 to encroach upon the chest, and contraction of the right allows 

 the liver to pass upwards. The heart and mediastinum will be 

 drawn towards the lung which is contracted, unless previously 



