THE POSTERIOR THORACIC WALL 515 



carcinoma of the oesophagus, the mediastinum must be exposed 

 more widely. Access is obtained by reflecting a large musculo- 

 cutaneous flap, about four inches wide, which has its base over 

 the vertebral spines. When the upper part of the oesophagus 

 is attacked, the flap extends from the first to the seventh 

 intercostal space. The medial portions of four ribs are resected 

 subperiosteally, and after the intercostal vessels have been 

 ligated the periosteum and intercostal muscles are carefully 

 incised at the medial part of the wound. 



Owing to the position of the descending thoracic aorta 

 (Fig. 154) this operation is usually performed on the right side, 

 and it must be remembered that the right pleural sac forms a 

 small recess behind the right border of the oesophagus (Fig. 154). 



Innominate artery 



Left innominate vein T> u 



"/xgjjSti /^j^^ /^fiO Kignt innominate vein 



& ' 99 m 



Left common carotid a. 



Left subclavian a. I) ((j^^^k^T Trachea 



Left recurrent nen^-^ B^ Mediastinal pleura 



Thoracic duct -\jg|||||^ (E SO p hagus 

 Mediastinal pleura 



-- Body of vertebra 



FIG. 155. Transverse Section through the Superior Mediastinum. 



The pleura is stripped off the heads of the ribs, the side of the 

 vertebral column, and the oesophagus, and, if this is done 

 carefully, there is little danger of injuring the sympathetic 

 trunk, which descends on the heads of the ribs. The oesophagus, 

 which can, if necessary, be identified by passing an cesophageal 

 bougie, can now be freed and brought to the surface, a distance 

 of about four inches. 



When the oesophagus is exposed on the right side below the 

 root of the lung, care must be taken not to injure the vagus nerve, 

 which descends along its lateral border. In this situation the 

 vena azygos and the thoracic duct, which lie behind the oesophagus, 

 are not likely to be injured, as they tend to remain in contact 

 with the vertebral column when the pleura is stripped away 

 and the oesophagus is brought to the surface. At the upper 

 border of the root of the right . lung the vena azygos turns 



