384 



The Heart. 

 Ramus dexter a. pulmonalisi 



Arcus aortac 



Eamus sinister 

 a. pulmonalis 



Atrium sinistrum - 



Vv. pulmonales^. 

 sinlstrae 



,V. obliqua 



atrii sinistri-. 



[MarshalliJ 



V. cordis magna- 



V. posterior, 

 ventriculi 



sinistri 



Sinus 

 coronarius' 



^ Y. cava superior 



~^Vv. pulnionales 

 dextrae 



Atrium dextrum 



v. cava 

 inferior 



Ventriculus- 

 sinister 



V. cordis 

 parva 



V. cordis 

 anterior 



Ventri cuius 

 dexter 



_ V. cordis media 



Eamus descendens posterior 

 a. coronariae [cordis] dextrae 



Sulcus longitudinalis posterior 



430. The veins of the heart, viewed from below. 



Most of the veins of the heart open into the sinus coronarius. This lies in the lower 

 part of the sulcus coronarius, extends to the left as far as the opening of the v. obliqua atrii 

 sinistri [Marshalli] and opens at the right into the right atrium (see Fig. 422); it arises from 

 one part of the embryonic sinus reuniens (see also p. 376) and, as such, possesses cross-striped 

 (cardiac) muscle-fi))('rs. The veins opening into the sinus are partly closed at their mouths b_y' 

 valves, which, elsewhere, are absent. All the veins of the heart anastomose with one another. 



The V. cordis parva opens from the right into the sinus ; it runs in the sulcus coro- 

 narius and comes ])artly from the right ventricle, partly from the right atrium. 



The V. cordis media extends in the sulcus longitudinalis posterior from the apex of the 

 heart to the base; it receives its branches from both ventricles and opens from the right 

 into the sinus. 



The V. ohlvjua atrii sinistri [Marshalli] (0. T. obli((ue vein of Marshall) runs downward 

 as a small branch on the left side of the left atrium in iront of the pulmonary veins giving 

 rise to a more or less distinct fold of the epicardium (Ikj. venae cavac sinislrae) (see Fig. 412); 

 it opens from the left into the sinus and is a remnant of the embryonic v. cava sinistra. 



