586 



CIRCULATORY APPARATUS. 



right ventricle, is very oblique downwards and backwards ; it niclines on the 



sternum more or less, according to su])jects. 



The posterior border, much shorter than the anterior, is nearly vertical. 



Superiorly, it is separated from the diaphragm 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 is related on the 

 Fig- 350. right, in front, and behind, to the 



auricles ; it gives off on the left, 

 and a little in front, the two 

 arterial aortic and pulmonary 

 vessels. 



B. Auricular Mass. — Elon- 

 gated from before to behind, dis- 

 posed like a crescent above the 

 right side of the base of the 

 ventricles, constricted in its middle 

 part, on the limit of the two 

 auricles, the auricular mass pre- 

 sents for study three faces, two ex- 

 tremities, and a base. 



The superior face is divided by 

 a middle constriction into two 

 convex sections, each of which 

 corresponds to an auricle. The 

 anterior — or right section— shows 

 the entrance of the anterior vena 

 cava and vena azygos ; the pos- 

 terior — or left section — that of the 

 pulmonary veins. The trachea, 

 bronchi, and pulmonary artery pass 

 above this face (Figs. 349, 350). 



The right face, the most ex- 

 tensive in the anteo-posterior 

 direction, is divided like the pre- 

 ceding, 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. 350). 



The left face, concave from 



before to behind, includes the arterial trunks which leave the base of the heart. 

 Each of the extremities — anterior andposterior — constitutes a detached portion, 



named the appendix auricularis ; these appendages are curved towards each other 



in being flattened above and below. Their convex border is more or less 



crenelated, like the margin of a cock's comb, and their culminating portion 



advances nearly to the pulmonary artery, above the trunk of the cardiac 



vessels (Fig. 349). 



THE HEART AND PRINCIPAL VESSELS (RIGHT FACE). 



o, Right ventricle ; 6, left ventricle ; c, right auricle ; 

 d, anterior vena cava ; e, vena azygos ; /, posterior 

 vena cava ; g, g, pulmonary veins ; h, h, divisions 

 of the pulmonary artery ; i, posterior aorta ; j, an- 

 terior aorta; k, thoracic duct; /, right cardiac 

 artery ; m, its vertical o*- ventricular branch ; n, its 

 horizontal or auriculo-ventricular branch ; o, ven- 

 tricular branch of the cardiac vein; p, auriculo- 

 ventricular branch of the same. 



