Pericarditis 



159 



ducing a friction-sound. This sound may in time disappear from one 

 of three causes : from the deposit clearing up and leaving the surfaces 

 once more smooth and moist ; from adhesion occurring between heart 

 and pericardium ; or from effusion of serum collecting between and 

 separating them. In the last case the normal heart-sounds are, of 

 course, masked. 



A pericardial friction-sound does not cease, as does a pleural rub, 

 when the patient holds his breath, but in either case the sound may 

 be exaggerated by pressure made by the end of the stethoscope ; 

 against such a fallacy the listener must be on his guard. On account 

 of the pain associated with pericarditis, the diaphragm and the lower 

 intercostals keep quiet in respiration, the work being done in the upper 

 thoracic region. 



When the visceral and parietal layers of the pericardium are in- 

 flamed and sticky with lymph they may closely adhere. But often the 

 movements of the heart prevent 

 such adherence ; and the con- 

 stant unglueing of the opposed 

 surfaces renders each of them 

 rough or even shaggy. 



In pericardial effusion the 

 area of absolute dulness is pear- 

 shaped, with the small end up- 

 wards ; whereas in hypertrophy 

 and dilatation of the heart (p. 

 175) the shape of the dull area 

 and the direction of its greater 

 diameter are transverse. In 

 pericardial effusion, also, the 

 left end of the dulness reaches 

 beyond the apex-beat a most 

 important diagnostic sign but 

 when the distending fluid is 

 abundant the heart is insulated 

 within it, and the apex can no 

 longer beat against the chest- 

 wall ; the cardiac sounds are 

 then practically drowned in the 

 fluid, and the apex-beat may be 

 altogether indistinguishable. 



When the distension of the 

 sac is only partial, the area of 

 dulness may be made to shift 



.,, *, ,. j , Effusion into pericardium, A ; lungs, B, B, pushed 



its Site with the altered position aside> SdUrer, c, depressed. (SIBSON.) 



of the patient (much as de- 

 scribed in abdominal ascites, p. 316). The lungs being thrust from the 



