504 THE THORAX AND VERTEBRAL COLUMN 



sternal end of the second intercostal space. The pectoralis 

 major is split, and the' anterior intercostal membrane and the 

 internal intercostal muscle are divided in the line of the incision. 

 The vessels are then exposed, half an inch from the sternum,, 

 lying on the parietal pleura. 



A few lymph glands are associated with the internal mammary 

 vessels at the medial ends of the second and third intercostal 

 spaces (p. 26). 



In the operation of Paracentesis Thoracis an exploring 

 needle is introduced into the pleural sac through one of the 

 intercostal spaces overlying the dull area. In order to avoid 

 injuring the intercostal vessels and nerve, the needle is inserted 

 close to the upper border of the rib which forms the lower 

 boundary of the space selected. When the puncture is made 

 through the lower part of the thoracic wall, the needle should 

 be directed upwards and inwards as soon as it enters the pleural 

 sac, lest the diaphragm be penetrated. During the operation 

 the skin over the selected space is drawn upwards so that, when 

 the needle is withdrawn, the track of the puncture is practically 

 obliterated. 



In Empyasma an incision is made along the eighth or ninth 

 rib, with its centre in the posterior axillary line. During the 

 operation, the patient lies on the sound side with the arm of the 

 other side flexed and adducted. In this position the inferior 

 angle of the scapula is drawn forwards and upwards, and the 

 seventh rib is exposed. Care must be taken to make certain 

 that the incision is not made over the seventh rib, as the wound 

 would be subsequently obstructed by the scapula when the arm 

 resumed its normal position. 



The skin and fasciae and the lower border of the latissimus 

 dorsi, which is exposed in the posterior part of the incision, are 

 all divided, and the wound is deepened through the serratus 

 anterior. The rib is then exposed and an incision is made 

 through the periosteum in its long axis. A transverse cut is 

 made at each extremity of this incision, and the periosteum is 

 then stripped off both surfaces of the rib. A portion of the rib 

 can be resected without injuring the intercostal vessels and 

 nerves. The wound is then deepened through the inner layer 

 of the periosteum and the costal pleura. The pus must not 

 be allowed to escape too rapidly as the sudden diminution of 

 pressure may lead to heart-failure. A large tube is fixed in 

 position and the edges of the wound are drawn together. 



