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The Heart 



of a sinus and an appendix. Into the upper part of the sinus, behind 

 and to the right side, the superior cava pours its contents in such a 

 manner that the blood, descending from it, falls against the opening into 

 the right ventricle. In the foetus this stream passes in front of, and 

 does not blend with, the wave of pure blood which is entering the 

 auricle by the inferior cava and leaving it by the foramen ovale. 



10 



Interior of right heart : 



1, Sup. cava. 



2, Inf. cava, with 



hepatic veins. 



3, Septum and fossa. 



4, Pulmonary valve. 



5, Tricuspid valve. 



6, Pulmonary art. 



7, Ductus art. 



10, Left appendix. 



11, Left ventricle. 



The inferior vena cava opens into the lowest part of the auricle, 

 sending its blood upwards and inwards against the inter-auricular 

 wall, for this was the direction which it took in foetal life, passing 

 through the foramen ovale under the protection of the Eustachian valve. 

 This valve is a reduplication of the auricular lining, and is attached by 

 its convex border at the front of the inferior cava and just behind the 

 auriculo-ventricular opening. 



The fossa ovalis is on the inter-auricular septum, and marks the 

 position of the foramen ovale by which, in the foetus, the pure blood 



