THE HE ART 



937 



the heart (interventricular), around wliieh it sends branches to anastomose with 

 the right coronary; whilst the other winds to the back of the heart in the auricul(j- 

 ventricular groove, to anastomose after division with the corresi)onding twigs of 

 the right artery. In this course it gives off a branch which descends near the left 

 border of the heart (left marginal), as well as smaller branches to the left auricle, 

 both ventricles, and the cDiiniicncement of the aorta and pulmonary vessels. 



The cardiac oi- coronary veins accompany the coronary arteries and return 

 the blood from the walls ol' tht; heart. 



The (so-called) great cardiac vein ascH'uds in the anterior interventricular sul- 

 cus, ])assing round tlu' left side of the heart to its posterior surface in the auriculo- 

 ventrieular groove to terndnate in the commencement of the coronary sinus. Its 

 mouth is usually guarded bv two valves, and it receives in its course the left 



Fig. 556. — Posterior View of the He.\rt, showing its Arteries and Veins. 



liiyhl caiidid aitefy 



Left carotid artery 

 Left subclarUiii iirleri/ 



Aorta - 

 Ductus arteriosus 



Pulriionary artery 

 LeJ'l imlmonary veins 

 LEFT AURICLE 

 Left coroitarij artery 

 Left marginal artery - 

 Oblique rein of Marshall 

 Left marginal vein ' 

 PERICARDIUM ^ 

 Coronary sinus _ 



Posterior cariliav I • 



A nterior interventricular 

 brancli of left coronary 



lunoniinute artery 



Vena cava sui>eriur 

 Hiylit jjuhiKiiuny vHus 



- RIGHT AURICLE 



\'eiia cava iuferior 



I'iylit coronary artery 

 Posterior iulerventriculur rein 



I'usterior interventricular liranch 

 of right coronary 



marginal vein, with other smaller veins from the left aiiriek' (the left auricular) 

 and ventricle, all of which are guarded by valves. 



The posterior cardiac vein (posterior interventricular ), sometimes the larger 

 of the two chief veins, connnunicates with the foregoing at its commencement on the 

 anterior surface above the heart's apex. It ascends in the })osterior interventricular 

 groove, receiving blood from the ventrieidar walls, and joins the coronary sinus, 

 tbi'ougb an orifice guarile<l by a single valve, close to its termination. 



The anterior cardiac veins ( preventricular ) consist of several small br.inebes 

 from the front of tlie right ventric-le, wliieh o])en separately into the riLdit aurieli-, 

 or into the right auricular vein; and a right marginal vein ( vein of Galen ), which 

 joins the coronary sinus near its termination, or opens separately into the lower 

 part of the right auricle (Figs. 549, 555). 



The coronary sinus may lie regarded as a much dilated terminal portion of the 

 great cardiac vein. It is about an inch in length, covered by muscular lil)res from 



