THE HEART. 



207 



WOUNDS OF THE HEART. 



Wounds of the heart are usually immediately fatal, but sometimes they are not 

 so. The pleurae are very liable to be wounded at the same time. The right ven- 

 tricle, on account of lying anteriorly, is the part most often involved. The atria lie 

 more posteriorly and are most apt to be wounded in stabs through the back. Not 

 only may the substance of the heart itself be injured but also its blood-vessels. The 

 right coronary artery lying in the atrioventricular groove and the anterior interven- 

 tricular branch of the left coronary running between the two ventricles anteriorly are 

 the vessels most liable to injury. Owing to the heart being enclosed in the peri- 

 cardium, a closed sac, if blood accumulates in it the action of the heart is inter- 





FIG. 221. Percussion area of the liver and heart. The light shaded area represents the extent of deep or relative 

 dulness and the dark shaded area that of superficial or absolute dulness. 



fered with. To avoid this occurrence, wounds bleeding externally should not be 

 closed, or distention of the pericardium may ensue. 



Wounds of the heart have been sutured successfully. In order to reach the 

 heart, a portion of the chest-wall would have to be resected and turned to one side 

 as a flap. This wilj probably require the opening of the pleural cavity. The pleurae 

 will in all likelihood already have been involved and found to be filled with blood, as 

 has occurred in at least one case. 



A knowledge of the exact outlines of the heart as already given will often 

 enable one to decide as to whether a wound involves the heart or not. 



