502 



THE CIRCJLATORY APPARATUS. 



Fig. 259. 



These two faces respond, through the medium of the pericardium, to the 

 plurae and the pulmonary lobes ; the latter separate them from the thorax, ex- 

 cept towards the middle and apex of the organ, where these faces come directly 

 in contact with the thoracic parietes through the notch at the inferior border 

 of the lung, and which we know is more marked in the left than the right. 

 The borders are thick, smooth, and rounded. The anterior, formed by 



the right ventricle, is very 

 oblique from above to below, 

 and before to behind ; it then 

 inclines on the sternum more 

 or less, according to the sub- 

 jects. 



The posterior border, much 

 shorter than the anterior, is 

 nearly vertical. Superiorly, 

 it is separated from the dia- 

 phragm by the lung; but, 

 below, it is quite close to 

 that muscular septum. 



The apex, or point of the 

 ventricular cone, is blunt, 

 slightly rounded, turned to 

 the left, and formed entirely 

 by the left ventricle. 



The base responds on the 

 right, in front, and behind, 

 to the auricular mass ; it gives 

 exit on the left, and a little 

 in front, to the two arterial 

 aortic and pulmonary trunks. 



B. AURICULAR MASS. 

 Elongated from before to be- 

 hind, disposed like a crescent 

 above the right side of the 

 base of the ventricles, con- 

 stricted in its middle part, 

 on the limit of the two auri- 

 cles, the auricular mass pre- 

 sents for study three faces, 

 two extremities, and a base. 



The superior face is di- 

 vided by a middle constric- 

 tion into two convex sections, 

 each of which corresponds to 



THE HEART AND PRINCIPAL VESSELS ; RIGHT FACE, 

 a, Right ventricle ; b, Left ventricle ; c, Right auricle ; 

 d, Anterior vena cava ; e, Vena azygos ; /, Posterior 

 vena cava; g, g, Pulmonary veins; A, A, Divisions 

 of the pulmonary artery; i, Posterior aorta; j, An- 

 tenor aorta; k, Thoracic duct; /, Right cardiac 

 artery; m, Its vertical or ventricular branch; , Its 

 horizontal or auriculo-ventricular branch ; o, Ven- 



" Auric " 10 ' 



. . 



right section, shows the in- 

 sertion of the anterior vena cava and vena azygos ; the posterior, or left, 

 that of the pulmonary veins. The trachea, bronchi, and pulmonary artery 

 pass above this face (Figs. 258, 259). 



The tight face, the most extensive in the antero-posterior direction, is 

 divided like the preceding, and disposed in a similar manner. The right, or 

 anterior part, receives, behind and below, the insertion of the posterior vena 

 cava, and the coronary and bronchial veins (Fig. 259). 



