Heart. 



181 



523. The Opening of the Coronary Vein into the 

 Right Auricle. 



View from behind. After a dried specimen, natural size. 



In the right auricle there is also the coronary valve or 

 Valvula Thebesii, a semicircular fold of the lining membrane of the 

 auricle , protecting the orifice of the coronary sinus. The Foramina 

 Thebesn are numerous minute apertures , the mouths of small veins, 

 which open on various parts of the inner surface of the auricle. 



The Eustachian valve is a crescentic fold of the lining membrane, 

 which is an important structure in the foetal heart, serving the purpose 

 of directing the stream of blood from the inferior Vena cava through 

 the Foramen ovale into the left auricle. Its convex margin is attached 

 to the wall of the Vena cava, its free concave margin terminates in 

 two cornua, of which the left is attached to the anterior edge of the 

 Annulus ovalis. The Tuberculum Loweri is not visible in the hearts of 

 adults; it is a small projection on the right wall of the auricle between 

 the two Venae cavae. Both the coronary valve and the Eustachian valve 



may be found fenestrated. 



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