THE CIRCULATORY A1TAHATUS. 



Fig. 259. 



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

 plnrto and tho pulmonary lobes ; tho latter separate them from tho thorax, ex- 

 cept towards tho middle and apex of tho organ, where these faces conic directly 

 in contact with tho thoracic parietcs through tho notcli at the inferior bonier 

 of the lung, and which wo know is more marked in the loft than the right. 

 Tho borders are thick, smooth, and rounded. Tho antcrim; formed by 



tho right ventricle, is very 

 oblique from above to In-low, 

 and before to behind ; it then 

 inclines on tho sternum more 

 or less, according to the sub- 

 jects. 



The jxw/en'or border, much 

 shorter than tho anterior, is 

 nearly vertical. Superiorly, 

 it is separated from the dia- 

 phragm by the lung; but, 

 below, it is quite closo 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. 



Tho base responds on tho 

 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. AURICULAE 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 tho 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, 



horizontal or nuriculo-ventricular branch ; o, Ven- each of which corresponds to 

 tricular branch of the cardiac vein; p, Auriculo- ftn auriclo> Tho anterior or 

 ventricular brunch of the same. . , , ,. , ., '. 



right section, shows the in- 

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

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

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



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

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

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

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



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- 

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

 artery ; in, Its vertical or ventricular branch ; n, Its 



