Inferences made regarding the postnatal anatomy of the atrial septum still tend to be based on developmental evidence. Although atrial septation is a well-defined process, it is remarkably complex and remains poorly understood. It is now established, however, that the process involves the conjugation of several myocardial structures and mesenchymal tissues of both intracardiac and extracardiac origin. The resultant postnatal morphology is equally complex, evidenced by the fact that, in the normal heart, only the floor of the oval fossa, along with its anteroinferior muscular buttress, are true anatomical septums. In this regard, septums can be defined as partitions that can be removed without creating communications with the extracavitary space. The true septal components are surrounded by grooves, which themselves largely represent infolding of the atrial walls. These anatomical features can now accurately be revealed using virtual dissection of CT data sets. These images, when carefully reconstructed, demonstrated the anatomy with as much accuracy as when hearts are dissected in the autopsy room. Such virtual dissection, furthermore, shows the components as they are seen within the chest, thus facilitating understanding for those intending to undertake interventional therapeutic procedures. By preparing such images, we show the complexity of the normal atrial septum and its surrounds. We show that it is only defects within the oval fossa, or the much rarer vestibular defects, which can appropriately be illustrated in the context of a normally constructed heart.
- atrial septal defect
- cardiac computer tomographic (ct) imaging
- congenital heart disease
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Contributors SM designed the work, created the images and drafted the initial manuscript. TN helped create the images and made radiological revisions. JTT provided expertise on congenital heart disease and made critical revision of the manuscript. DES created the images and made anatomical revision. K-iH and RHA made critical revision and provided final approval of the manuscript.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent Not required.
Ethics approval The study was granted institutional review board approval by Kobe University Graduate School of Medicine.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement Individual data can be shared upon request.
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