What is the real cardiac anatomy?

Abstract

The heart is a remarkably complex organ. Teaching its details to medical students and clinical trainees can be very difficult. Despite the complexity, accurate recognition of these details is a pre‐requisite for the subsequent understanding of clinical cardiologists and cardiac surgeons. A recent publication promoted the benefits of virtual reconstructions in facilitating the initial understanding achieved by medical students. If such teaching is to achieve its greatest value, the datasets used to provide the virtual images should themselves be anatomically accurate. They should also take note of a basic rule of human anatomy, namely that components of all organs should be described as they are normally situated within the body. It is almost universal at present for textbooks of anatomy to illustrate the heart as if removed from the body and positioned on its apex, the so‐called Valentine situation. In the years prior to the emergence of interventional techniques to treat cardiac diseases, this approach was of limited significance. Nowadays, therapeutic interventions are commonplace worldwide. Advances in three‐dimensional imaging technology, furthermore, now mean that the separate components of the heart can readily be segmented, and then shown in attitudinally appropriate fashion. In this review, we demonstrate how such virtual dissection of computed tomographic datasets in attitudinally appropriate fashion reveals the true details of cardiac anatomy. The virtual approach to teaching the arrangement of the cardiac components has much to commend it. If it is to be used, nonetheless, the anatomical details on which the reconstructions are based must be accurate. Clin. Anat. 32:288–309, 2019. © 2019 The Authors. Clinical Anatomy published by Wiley Periodicals, Inc. on behalf of American Association of Clinical Anatomists.

Why do we break one of the first rules of anatomy when describing the components of the heart?

“…Furthermore, the decline in donation of bodies, along with the decrease in numbers of autopsies (Goldman et al ; de Almeida et al ), now makes it more difficult for students to appreciate the true position of the heart within the body. On the other hand, the advent of new diagnostic imaging modalities and technologies permits the components of the heart to be shown with the organ properly positioned within the thorax (Mori et al ). This will serve to emphasize that many of the figures currently used to illustrate the anatomical components of the hearts are incorrect.…”

“…Those using tomographic imaging now correctly describe the diaphragmatic portion of the left ventricle as inferior, not “posterior,” as it is described by those retaining the Valentine nomenclature (Cerqueira et al ). Indeed, virtual dissection of computed tomographic datasets is increasingly becoming the gold standard for revealing the smallest details of cardiac anatomy; and such virtual dissection is necessarily performed with the heart located in the thorax in its attitudinally appropriate position (Saremi et al ; Sánchez‐Quintana et al ; Anderson and Mori ; Mori et al , ). The same caveats apply to the use of three‐dimensional echocardiography, which again reveals the details of cardiac anatomy as shown with the heart in its attitudinally correct location (Fagan et al ; Njeim et al ).…”

“…The same caveats apply to the use of three‐dimensional echocardiography, which again reveals the details of cardiac anatomy as shown with the heart in its attitudinally correct location (Fagan et al ; Njeim et al ). With the increasing use of all these diagnostic techniques, logic dictates that the structures should be described as seen within the heart in the thorax (Sánchez‐Quintana et al ; Anderson and Mori ; Mori et al , ). The resolution of the current deficiencies will be expedited if teachers of human anatomy, in the first instance, are prepared to adopt the attitudinally appropriate approach.…”

“…Those promoting the virtual approach to teaching (Maresky et al ) should also prepare their models in attitudinally correct fashion. Although the use of attitudinally correct nomenclature is still not widely accepted, it is validated by the virtual dissections of computed tomographic datasets (Mori et al ). The increased use of such resources by clinicians will also emphasize the need to use the appropriate descriptions.…”

“…Can all these problems be resolved? The future use of attitudinally appropriate nomenclature is the easiest problem to fix, since the advent of images based on virtual dissection of computed tomographic datasets (Mori et al ) will make it easy for teachers to demonstrate and describe the heart as it lies within the chest. However, learning the classical anatomy of the heart by studying cadaveric specimens remains the prerequisite for understanding what can be delivered by modern imaging (Sánchez‐Quintana et al ).…”