STRUCTURE OF HEARTHS VALVES. 93 



mitral of four, portions. Each portion is of triangular form, 

 its apex and sides lying free in the cavity of the ventricle, and 

 its base, which is continuous with the bases of the neighboring 



FIG. 34. 



The right auricle and ventricle opened, and a part of their right and anterior walls 

 removed, so as to show their interior. %. 1, superior vena cava; 2, inferior vena 

 cava ; 2', hepatic veins cut short ; 3, right auricle ; 3', placed in the fossa ovalis, below 

 which is the Eustachian valve ; 3", is placed close to the aperture of the coronary 

 vein; +, +, placed in the auriculo-ventricular groove, where a narrow portion of 

 the adjacent walls of the auricle and ventricle has been preserved ; 4, 4, cavity of the 

 right ventricle, the upper figure is immediately below the semilunar valves; 4', 

 large columna carnea or musculus papillaris ; 5, 5', 5", tricuspid valve ; 6, placed in 

 the interior of the pulmonary artery, a part of the anterior wall of that vessel having 

 been removed, and a narrow portion of it preserved at its commencement where the 

 semilunar valves are attached ; 7, concavity of the aortic arch close to the cord of 

 the ductus arteriosus ; 8, ascending part or sinus of the arch covered at its com- 

 mencement by the auricular appendix and pulmonary artery ; 9, placed between the 

 innominate and left carotid arteries , 10, appendix of the left auricle ; 11, 11, the out- 

 side of the left ventricle, the lower figure near the apex. (From Quain's Anatmy.) 



