. Cunningham's Text-book of anatomy. Anatomy. Fig. 829. Interventricular sulcus -Section of the Heart of a Human Embryo. (Edinburgh University collection.) 6th aortic arches^1. 4th aortic arches, Septum spurium Left duct of Cuvier Left anterior \ cardinal veins \ Septum primum Atrio-ventricular orifice Bulbus cordis of the truncus arteriosus and the adjacent part of the bulbus cordis; and (2) the primitive atrium is divided into the right and left per- manent atria by the forma- tion of two interatrial septa. By the ventral growth of the right and left margins of the atrium the auricles of the
. Cunningham's Text-book of anatomy. Anatomy. Fig. 829. Interventricular sulcus -Section of the Heart of a Human Embryo. (Edinburgh University collection.) 6th aortic arches^1. 4th aortic arches, Septum spurium Left duct of Cuvier Left anterior \ cardinal veins \ Septum primum Atrio-ventricular orifice Bulbus cordis of the truncus arteriosus and the adjacent part of the bulbus cordis; and (2) the primitive atrium is divided into the right and left per- manent atria by the forma- tion of two interatrial septa. By the ventral growth of the right and left margins of the atrium the auricles of the right and left per- manent atria are formed, and by the formation and fusion of the two interatrial septa the permanent inter- atrial septum of the fully de- veloped heart is established. The septa by which the atrial chamber is divided are the septum primum and the septum secundum; so named because the first ap- pears and partly disappears ln'fore the second is formed. Both the septum primum and the septum secundum grow from the dorsal towards the ventral wall of the primitive atrium, the septum secundum to the right of the septum primum. When the septum primum reaches the ventral wall of the atrium it fuses with the dorsal ends of the endocardial cushions of the atrio-ventricular canal. Until this fusion occurs an aperture, the •primary foramen ovale, exists between the two atria and a number cf perforations are formed in the more dorsal portion of the septum ; therefore the passage of blood from the inferior vena cava through the right part of the atrium into the left part is never Right posterior / cardinal vein j / ^ Ventricle Right duct of Cuvier i' Left venous valve ; Right venous valve Fig. 830.—Model showing the Interior of the Right Atrium of i Human Embryo 5'5 mm. long. (Edinburgh, University collection Modelled by C. C. Wang.). Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectanatomy, bookyear1914
