Heart showing expansion of the atria.
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| colspan="2" |Diagrams to illustrate the transformation of the bulbus cordis. (Keith.) Ao. Truncus arteriosus. Au. Atrium. B. Bulbus cordis. RV. Right ventricle. LV. Left ventricle. P. Pulmonary artery.
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|Latin
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|colspan="2"|[subject #135 ]
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|System
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|Carnegie stage
|colspan="2"|[9]
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|Days
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|Precursor
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|Gives rise to
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|MeSH
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|Dorlands/Elsevier
|colspan="2"|[b_26/12200235]
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When the heart assumes its S-shaped form the bulbus cordis lies ventral to and in front of the primitive ventricle.
The adjacent walls of the bulbus cordis and ventricle approximate, fuse, and finally disappear, and the bulbus cordis now communicates freely with the right ventricle, while the junction of the bulbus with the truncus arteriosus is brought directly ventral to and applied to the atrial canal.
By the upgrowth of the ventricular septum the bulbus cordis is in great measure separated from the left ventricle, but remains an integral part of the right ventricle, of which it forms the infundibulum.
