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THE VEIXS 



The coronary sinus is situated at the hack of the heart, in tlie groove lietween 

 the left auricle and left ventricle. It measures about an inch in length. Its 

 opening into the auricle is guarded by the so-called Thebesian or coronary valve. 

 It receives the following tributaries: (1) The great coronary or cardiac vein, of 

 which it appears to be the large and dilated end; (2) the posterior cardiac or pos- 

 terior interventricular vein; (3) the right auricular vein; and (4) the oblique vein. 



(1) The great coronary or cardiac vein is formed by the union of (a) the 

 anterior interventricular vein, which runs upwards from the apex of the heart, 

 in the groove between the right and left ventricles, in comi)any with the artery of 

 that name; with (h) the left auricular vein, which returns the blood from the left 

 auricle. The vein thus formed then runs round the left side of the heart, in the 

 groove between the left auricle and left ventricle, and terminates in the coronary 

 sinus at the spot where the latter is joined by the oblique vein. Its entrance into 

 the sinus is guarded by a double valve. It receives (c) the left marginal vein or 

 veins, and branches from both ventricles, especially the left. 



The left marginal vein runs with the artery of that name over the surface of 



Fig. 384. — Scheme of the Coronary Veins. (Walsham.) 



Right pulmonary veins ! I > / 1 Superior vena cava 



Left pulmonary veins 

 Inferior vena cava 



Oblique vein 



Great coronary or 

 cardiac vein 



Left marginal vein 



Anterior inlerien- 

 Iricular vein 



Preventricvlnr or 

 anterior cardiac 

 vein 



night auricular vein 



Coronary ^inus 



Posterior or middle 

 cardiac or posterior 

 interventricular vein 



Right marginal vein 



the left ventricle, along the left margin of the heart. It receives tributaries from 

 the left ventricle, and terminates in the great coronary vein. 



(2) The posterior cardiac, middle cardiac, or posterior interventricular 

 vein accompanies the posterior interventricular artery upwards, from the apex of 

 the heart in the posterior interventricular groove. It ends in the coronary sinus, 

 just before the termination of the latter in the right auricle. It receives tributaries 

 from the posterior surface of both ventricles, and is guarded by a valve where it 

 joins the coronary sinus. Two or three small veins (posterior "cardiac, or smaller 

 posterior cardiac) run upwards from the back of the left ventricle, and open into 

 the coronary sinus by sejiarate orifices guarded by valves. 



(3) The right auricular, right coronary, or small coronary vein, runs in the 

 right auriculo-ventricular groove, and terminates in the coronary sinus just before 

 the entrance of that sinus into the auricle. It is joined by "the riglit marginal 

 vein and by the preventricular or smaller anterior cardiac vein or veins. 



(4) The oblique vein — the greater ])art of which is often represented merely by 

 a delicate til)r(nis cord — runs across the l)ack 2)art of the left auricle, in the vestigial 

 fold of the pericardium to tlie coronary sinus. This vein, with the coronary sinus, 



