The Heart. 



383 



Ramus dexter a. pulnionalis 



Arcus aortae 



Raiims sinister 

 . a. pulmonalis 



Atrium sinistrum - - 



Vv. pulmonales 



sinistrae 



V. cava superior 



r '~'_s~-~- Vv. pulmonales dextrae 



itrium dextrum 



.V. cava 

 inferior 



Ligameutum 

 V. c^vae sinistrae" 



Mouth of 



the sinus 



coronarius 



A. coronaria 

 [cordis] sinistra 



Ventriculus 

 sinister 



A. coronaria 

 [cordis] dextra 



Ramus descendens 



posterior 



_ Ventriculus dexter 



Sulcus longitudinalis posterior 



< i / 



Ramus descendens anterior a. coronariae [cordis] sinistrae 



429. The arteries of the heart, viewed from below. 



The a. coronaria [cordis] sinistra (left coronary artery) (see also Fig. 428) arises from 

 the left sinus aortae [Valsalvae] (see Figs. 426 and 433)/ is usually larger than the right, and 

 divides just after its origin into two branches. The ramus descendens anterior extends at first 

 behind the a. pulnionalis, then to the left from it, covered by the left auricle, to the sulcus 

 longitudinalis anterior, in which it runs as far as the incisura [apicis] cordis, usually going over 

 to a certain extent upon the facies diaphragmatica : it gives off larger branches to the septimi 

 ventriculorum and the left ventricle and smaller branches the right ventricle. The ramus ciixum- 

 flexus, hidden below the left auricle, goes in the sulcus coronarius first to the left, then upon 

 the facies cUaphragmatica to the right and does not reach the sulcus longitudmalis posterior; 

 it gives off larger branches to the left ventricle and smaller ones to the left atrium. 



Both aa. coronariae anastomose manifoldly with one another by means of minute branches 

 (larger than capillaries), usually inside the muscle, more rarely on the surface just beneath 

 the epicardium. 



25* 



