452 



DISSECTION OF THE THORAX. 



Nerves. 



The heart 

 is hollow. 



Form: 

 anterior 

 surface ; 



Nerves. According to Luschka the pericardium receives nerves 

 from the phrenic, sympathetic, and right vagus. 



THE HEART AND ITS LARGE VESSELS. 



The heart is a hollow muscular organ by which the blood is 

 propelled through the body. Into it, as the centre of the vascular 

 system, veins enter ; and from it the arteries issue. 



Form (figs. 164 and 165). The heart is conical in form, but 

 somewhat compressed from before backwards. The anterior surface, 

 formed by the right ventricle and portions of the right auricle and 



inferior 

 surface ; 



posterior 

 surface ; 



right 

 border. 



Size and 

 weight. 



3up.Vena 

 Co.-- 



FIG. 164. THE HEART SKEN FROM THE FRONT AND THE LEFT SIDE. THE 

 DUCTUS ARTERIOSUS is CUT ACROSS AND THE AORTA LIFTED UP TO 

 SHOW THE RIGHT BRANCH OF THE PULMONARY ARTERY. 



(From a specimen in Charing Cross Hospital Museum). 



the left ventricle, is convex ; the inferior surface, where it rests on 

 the diaphrag in, is formed by a great part of the left and a portion 

 of the right ventricle, and is nearly flat ; the posterior surface, 

 formed by the left auricle and portions of the left ventricle and 

 right auricle, is nearly flat and somewhat quadrilateral in outline, 

 left border; The left border, formed by the left ventricle, is thick and rounded ; 

 while the right, formed by the right auricle and a portion of the 

 ventricle, is thin and less firm. 



Size. The size of the heart varies greatly ; and it is usually 

 smaller in the woman than in the man. Its average measurements 

 may be said to be about five inches in length, three inches and 



