PRACTICAL CONSIDERATIONS: PERICARDIUM. 717 



The parietal layer of the pericardium is in relation with an external fibrous layer 

 which extends beyond the serous investment of the roots of the great vessels, blends 

 with their outer coats, and is directly continuous with the deep cervical fascia, thus 

 connecting the pericardium with two respiratory agents, the diaphragm below and 

 the cervical muscles (omo-hyoid) above. When these act conjointly, as in a full 

 inspiration, they render the pericardium tense and resisting, and minimize the pressure 

 upon the heart by the inflated lungs (page 551), 



Pericarditis — probably more often overlooked than any other serious disease 

 (Osier) — may arise from wound from without, as in ordinary penetrating wounds 

 of the chest, or from within, as from the passage of a foreign body from the oesoph- 

 agus into the pericardium (page 1614); or it may follow extension of disease from 

 contiguous organs, as in pleuro-pneumonia. The anatomical relations of the peri- 

 cardium explain these occurrences. The more usual causes, as rheumatism, septi- 

 caemia, gout, and nephritis, have no anatomical bearing. 



Pericarditis is attended by certain symptoms — well detailed by Sibson — which 

 should be studied in connection with the anatomy of the heart and pericardium. 



I. Pain — (a) spontaneous and directly over the heart, the pleurae often being 

 involved, both these serous membranes — like the peritoneum — becoming painful 

 when inflamed, although normally insensitive ; (<5) elicited by pressure (tenderness), 

 the skin over the precordium sometimes participating on account of the connection 

 between the upper intercostal nerves and the ganglia and nerves of the cardiac plexus ; 

 (f) over the epigastric region and increased by pressure, because, although normally 

 the pericardium below is in direct relation with the thoracic parietes over only a small 

 area behind the xiphoid cartilage, distention of the pericardial sac, as in effusion 

 from pericarditis, carries it downward so that it may be well below the tip of the 

 xiphoid ; (^) between the scapulae or deep in the chest, increased by swallowing or 

 by eructations, and worse when the patient is supine, due to the relation between the 

 oesophagus and pericardium just below the aortic arch ; (<?) in the side, usually 

 pleuritic (from extension), and more common on the left side on account of the 

 greater extent to which the inflamed pericardium occupies the left side of the chest 

 than the right side, to the marked backward displacement of the lower lobe of the 

 left lung by the distended pericardial sac, and possibly (Sibson) to the pressure 

 of the latter on the left bronchus increasing in the left lung the tendency to intercur- 

 rent pneumonia. 2. Feeble or irregular heart action, due to («) direct extension 

 of the inflammation from the visceral layer of the pericardium to the heart muscle 

 (myocarditis); i^b') implication of the cardiac nerves ; (<:) pressure by the pericardial 

 effusion on the venae cavae and pulmonary veins, impeding the blood-supply to both 

 auricles ; direct pressure upon the auricles interfering with the ventricular supply ; and 

 pressure upon the whole organ both directly from the effusion and indirectly from 

 the compressed and displaced lungs and the other contiguous structures, embarrass- 

 ing its action, especially in diastole. 3. Dyspncea, due to the pulmonary congestion 

 produced by the previous causes ; sometimes the result of a pleurisy or pleuro- 

 pneumonia by extension ; or perhaps, as Hilton has suggested, partly from fixation 

 or irregular action of the diaphragm through irritation of the pericardiac filament 

 of the phrenic (ramus pericardiacus), usually given ofT on the right side. 4. Dys- 

 phagia (page 1 6 14) from compression of the oesophagus between the pericardium 

 and the vertebral column, usually relieved when the patient is put in an approximately 

 vertical position. 5. Aphonia,, from involvement of the left recurrent laryngeal 

 nerve by contiguity, or of both nerves through their cardiac branches. 6. Fidness 

 of the cervical veins and fiushing or cyanosis of the face, due to pressure upon the 

 thin walls of the right auricle and of the superior vena cava. Compression of the 

 left auricle is better resisted on account of the greater thickness of its walls ; when 

 it occurs, it tends to produce pulmonary congestion or apoplexy. 



Th.e physical signs oi pericarditis are, of course, influenced by the attachment, 

 surroundings, and physical qualities of the pericardium. 



I . As it is in two layers normally movable upon each other, the roughenitjg caused 

 by inflammation produces z. friction-sound which., when typical, is (a) heard best over 

 the middle and the lower half of the sternum, and over the adjoining left costal 

 cartilages or their interspaces, because there a greater extent of the pericardium is 



