THE THORAX. 



223 



The aurta, the pulmonary arteries and veins, the cluctus arteriosus. 



ll'h'it i'ti n run say of I lie investment of the aorta and pulmonary artery ' 



1'hry are invested by a common slicath ; behind these vessels is a pa- 

 called tin LMvat sinus of the pericardium. 



.Vai/h /' valves of the hear/ and tlie valves of its vessels, and tell how they are 

 formed. 



The coronary, the Kustachian, the aortic and pulmonary semilunar, the right 

 and left auriculo-ventricular. They are formed by folds of endocardium and 

 subserous connective tissue. 



What are the gran<{ Divisions of tlie right auricle .' 



The auricular appendix and sinus venosus, or atrium. This auricle forms the 

 front part of the base of the heart. Into the atrium the following structures 



Right carvliil artery 



Isfl ftirolid urlerit 

 Left subclavian artery 



Aorta 

 Ductus arteriosvs 



Pulmonary artery 



Left pulmonary vein* 



LEFT AURICLE 



Left coronary artery 



Left marginal artery 



Oblique vein of Marshall 



Left marginal vein 



PERICARDIUM 



Coronary sinus _ 



Posterior cardiac vein 



Innominate artery 



Vena cara superior 

 Right pulmonary veint 

 RIGHT AURICLE 



\'ena cava inferior 



Bight coronary artery 

 Posterior interventricular rein 



Posterior interventricular branch 

 of right coronary 



vaam^ 



A nterior interventricular 

 branch of left coronary 



Kic. 157. POSTERIOR VIEW OF THE HEART, SHOWING ITS ARTERIES AND VEINS. 



open: (i) The descending vena cava; (2) the ascending vena cava; (3) the 

 auriculo-ventricular opening ; (4) the coronary sinus ; (5) the foramina of 

 Thebesii ; the foramen ovale in the foetus. 



What can yon say of the foramina of Tkebesins ? 



The most of them are blind sacs. Some are, however, perforate, and return 

 blood from the heart by the venae minimae cordis. The largest vein of this 

 group is called the vein of Galen. You will remember the veins of Galen 

 return the blood from the basal ganglia of the brain to the straight sinus of the 

 dura mater. To be specific in speech, then, speak of the veins of Galen of the 

 brain and of the heart. 



Xanie tlie openings in tlie right auricle having valves. 



The auriculo-ventricular, the coronary sinus, and the ascending vena cava. 



