386 



PERICARDITIS. 



producing operative pneumo-thorax when the cartihiges are resected to 

 admit of incising the pericardium. 



The only logical method seems to be puncture of the pericardium 

 through the xiphoid cartilage, as described below. 



The topographical anatomy of the thoracic viscera shows that the 

 point of the pericardium extends along the sternum to a point close to 

 the lower insertion of the diaphragm, and that the pericardial sac is 



^iH^L. 



r. Ax. F. 



Fig. 177.— Lesions of exudative iDeriearditis produced by a foreign body. Relation 

 of tbe j)ericardium to the sternum and ensiform cartilage. Pericardium opened. 

 D, diaphragm ; ffi, oedema of the dewlap, Ax, ensiform cartilage ; F, liver ; \b, gall 

 bladder ; 1, posterior lobe of the lung, drawn backwards ; 2, cardiac lobe ; 3, anterior 

 lobe ; E, spot where the foreign body penetrated, towards the point of the peri- 

 cardium, between the neck of the ensiform cartilage and the circle of the hypo- 

 chondrium. 



only separated from the xiphoid region, or rather from the region of the 

 neck of the xiphoid appendix of the sternum, by the fatty cushion at the 

 point of the heart. 



A glance at the annexed diagram (Fig. 177) will show this. 



The diagram, carefully reproduced from an anatomical preparation of 

 an animal which succumbed to pericarditis, shows that the distended 

 pericardium extends close to the neck of the xiphoid cartilage. 



First stage. Identify the three following anatomical guiding points : — 



(1.) Xiphoid appendix and white line. (2.) Point at which the circle of 



