THE PERICARDIUM. 201 



While the finger of one hand marks the interspace, an incision 4 cm. (\y z in.) 

 long is made along the upper edge of the rib, this is deepened by a couple of 

 strokes which detach the intercostal muscles and carefully penetrate the pleura. 

 As the pus makes its appearance the knife is withdrawn and the finger is laid on 

 the opening. A drainage-tube held in a curved forceps is then slid along the finger 

 into the chest. Sometimes a rubber tracheotomy tube is used for drainage purposes. 

 Any bleeding will be from the small intercostal branches and can readily .be stopped 

 by gauze packing. 



The incision is made along the upper edge of the rib because the intercostal 

 artery running along the lower edge of the rib is the larger. 



Resection of a Rib for Empyema. For the removal of a part of a rib a more 

 formal operation is necessary. The incision is made directly on the rib down to 

 the bone and five or more centimetres in length. The skin being retracted, the 

 periosteum is incised and detached from the rib with a periosteal elevator which is 

 passed down its posterior surface, pushing the pleura away from the rib. When 

 the elevator reaches the lower border of the rib an incision is made down on it 

 through the intercostal muscles, keeping as close to the rib as possible to avoid 

 wounding the intercostal artery, which lies close to its lower edge. The rib is 

 then divided either with a cutting forceps like Estlander' s, or a Gigli saw. The 

 rib, having been divided at one end of the incision, is then lifted up, the pleura 

 stripped off, and divided at the opposite end. 



Should the intercostal artery bleed, and it is often sufficiently large to spurt 

 quite actively, it can be caught with a haemostatic forceps and secured with a 

 ligature if necessary. This is safer than to trust to packing, on account of the 

 lack of support due to the removal of the rib. After the incision is completed, 

 the pleura is incised and the tube introduced. In ligating the intercostal artery, 

 care should be taken not to include the nerve which lies close to but below it; that 

 is, farther away from the rib. . 



THE PERICARDIUM. 



The pericardium is composed of fibrous tissue lined with a serous membrane. 



When affected by inflammation the amount of fluid contained in it becomes 

 increased and it becomes distended and may interfere with the functions of the heart 

 and adjacent structures. 



If the effusion is serous it is sometimes drawn off by puncture; if it is purulent 

 drainage is instituted. 



The pericardium in shape is somewhat conical. Its base rests on the central 

 tendon of the diaphragm and its apex envelops the great vessels, as they emerge 

 from the base of the heart, for a distance of 4 to 5 cm. The attachment to the 

 diaphragm is most firm at the opening of the inferior vena cava. As the fibrous 

 layer of the pericardium proceeds upward it becomes lost in the fibrous tissue 

 (sheath) covering the great vessels. This is continuous above with the deep cervical 

 fascia, especially with its pretracheal layer. Anteriorly the pericardium is attached 

 above and below to the sternum by the so-called sternopericardiac ligaments (Fig. 218). 



In front of it above are the remains of the thymus gland and triangularis sterni 

 muscle of the left side from the third to the seventh costal cartilages. The internal 

 mammary arteries, running down behind the costal cartilages about a centimetre 

 from the edge of the sternum above and somewhat more below, are separated *;. vn 

 the pericardium by the edges of the lungs and pleurae, these latter reaching nearl) or 

 quite to the median line. The triangularis sterni muscle also lies beneath the artery 

 and farther from the surface. As the left pleura slopes more rapidly toward the side 

 than does the right there is a small portion of the pericardium uncovered by the pleura 

 at about the sixth intercostal space close to the sternum. The incisura of the left 

 lung leaves a space where the pericardium is separated from the chest-walls only by 

 the pleura. 



On each side the pleura and pericardium are in contact, with the phrenic nerves 

 between them. Posteriorly the pericardium lies on the bronchi, the oesophagus, and 

 the thoracic aorta. 



