482 



CARDIAC VEIXS. 



colon. The trunk, formed by the union of its several branches, inclines 

 upwards and to the right side, passing in front of the duodenum and behind 

 the pancreas, where it joins with the splenic vein to form the venae portae. 



The branches of the inferior mesenteric vein correspond with the ramifica- 

 tions of the aitery of the same name. They commence at the lower part of 

 the rectum in the hsemorrhoidal plexus, and unite into a single vessel near 

 the sigmoid flexure of the colon. From this point the vein proceeds up- 

 wards and inwards along the lumbar region, behind the peritoneum, crossing 

 between the transverse mesocolon and the spine, or farther to the left, and 

 then passing beneath and behind the pancreas, it reaches the splenic vein 

 in which it terminates. 



VEINS OF THE HEART. 



The greater number of the cardiac veins are collected into a large common 

 trunk which pours its blood into the posterior part of the right auricle, in 

 the angle between the inferior vena cava and the right auriculo-ventricular 

 orifice. The terminal part of this vein is considerably dilated, and is named 

 the coronary sinus. The principal veins leading into it are named the great, 

 the posterior, and the anterior or small coronary veins. Among these the 

 first alone deserves the name of coronary, as it surrounds the heart in the 

 left auriculo-ventricular groove. 



Besides the larger cardiac veins which join the great coronary sinus, 

 there are also small separate veins (venae minimse cordis), which open 

 directly into the right auricle, especially along its right border. The open- 

 ings of these veins, as well as some depressions which do not admit veins, 

 have been named foramina Thebesii. 



Fig. 328. 



Fig. 328. VIEW OF THE ADULT HRART, FROM 



BEHIND, TO SHOW THE CORONARY VEINS. ^ 



a, placed on the back of the right auricle, 

 points to the Eustachiau valve seen within 

 the opening of the inferior vena cava ; &, the 

 back of the left auricle ; c, back of the right 

 ventricle ; d, left ventricle ; e, vena cava supe- 

 rior ; /, arch of the aorta ; 1, sinus of the 

 great coronary vein ; 2, great coronary vein turn- 

 ing round the heart in the auriculo-ventricular 

 groove ; 3, 4, posterior branches ; 5, one of the 

 small right cardiac veins passing directly into 

 the right auricle ; 6, the vestige of the left 

 superior vena cava proceeding over the left 

 auricle downwards to join the coronary sinus. 



The veins of the heart are without 

 valves excepting at their terminations. 



The great cardiac vein (vena cordis 

 magna) is a vessel of considerable size, 

 and, from the way in which it coils round 

 the left side of the base of the heart, 

 or rather of the ventricle, it may be 

 named "coronary." Its chief branch 

 runs along the groove upon the fore part of the heart, corresponding with 

 the septum of the ventricles. Commencing at the apex of the heart, it 

 gradually increases in size as it approaches the base of the ventricles, and 

 then, inclining backwards and to the left side in the groove between the left 



