THE LUNGS 351 



Posteriorly, the apex rests on the neck of the first rib and 

 the vertebral end of the first intercostal space. Two nerves 

 intervene between the rib and the pleura. They are the 

 sympathetic trunk and the anterior ramus of the first thoracic 

 nerve, which is passing upwards and laterally to take part in the 

 formation of the brachial plexus. Either of these structures 

 may be involved in the pleuritic thickening which accompanies 

 phthisis and apical pneumonia. When the sympathetic is 

 affected, certain vaso-motor symptoms may arise, such as uni- 

 lateral sweating or localised areas of flushing. Sometimes 

 the fibres which ultimately supply the dilatator pupillae muscle 

 are picked out, and the pupil on the affected side is markedly 

 dilated. Pressure on the sympathetic trunk may account for 

 the severe cerebral symptoms which occasionally complicate 

 cases of apical pneumonia. Involvement of the first thoracic 

 nerve is indicated by the presence of painful or hypersesthetic 

 areas on the medial side of the arm. 



Lombardi's "varicose zone of alarm," which is believed to 

 constitute an important aid to the early diagnosis of apical 

 phthisis, depends on the close relation of the intercostal veins 

 to the costal pleura. As they lie on the posterior thoracic wall, 

 the intercostal veins are in direct contact with the costal pleura. 

 The^rj/ intercostal vein arches forwards over the cupula pleurae 

 (p. 342) to join the innominate vein. The veins which drain 

 the second and third intercostal spaces unite to form the 

 superior intercostal vein. On the right side, this vessel joins 

 the vena azygos (major), which pours its blood into the superior 

 vena cava; on the left side, it crosses the arch of the aorta 

 obliquely and terminates in the left innominate vein. All the 

 intercostal vessels receive tributaries from the tissues of the 

 back as well as from the intercostal muscles, etc. 



The pleural thickening which is commonly associated with 

 apical phthisis may be sufficient to compress the veins which 

 drain the upper spaces, and, as a result, venous varicosities 

 occur on the dorsal aspect of the body near the seventh 

 cervical and the upper three thoracic spines. Owing to the 



