CHAPTER V. 



THE CIRCULATORY SYSTEM. 



The Pericardium. 

 INJURIES. 



THE pericardium maybe injured by penetrating weapons, by gunshot 

 wounds, and by fragments of bone. It may be ruptured by severe con- 

 tusions of the thorax, and by rapid extravasation of blood into the peri- 

 cardial sac. Perforations may occur with empyema, mediastinal abscesses, 

 abscesses of the chest wall and of the liver, or in connection with aneur- 

 isms of the aorta and suppurative inflammation of the pericardium. 



HEMORRHAGE. 



Extravasations of blood into the cavity of the pericardium may fol- 

 low wounds and rupture of the heart, rupture of the aorta and of aneur- 

 isms, and may occur with pericarditis. Small extravasations in the 

 substance of the pericardium are found with scurvy, purpura, and in 

 infectious diseases. 



HYDROPERICARDIUM. (Dropsy.) 



At autopsies a few hours after death a few cubic centimetres of clear, 

 light-yellow serum are usually present in the pericardial sac. If decom- 

 position have commenced, this may be reddish, or it may be slightly tur- 

 bid from the falliug-off of the pericardial endothelium. 



Large accumulations of clear yellowish serum are often found as part 

 of general dropsy from heart disease, kidney disease, etc. The amount 

 is sometimes so great as to interfere with the movement and nutrition of 

 the heart. 



PNEUMOPERICARDIUM. 



Air or gas in the pericardium is sometimes present as the result of 

 post-mortem decomposition and may be accompanied with drying of por- 

 tions of the pericardium. Wounds or paracentesis of the pericardium ; 

 the perforation of ulcers of the stomach, cavities of the lungs, and ulcers 

 of the ossophagus, may admit air into the pericardial cavity. In puru- 

 lent pericarditis with foul, decomposing exudate, gases may be evolved. 



