The importance of attitudinally appropriate description of cardiac anatomy.

The essence of anatomic description is to account for structures as they lie within the body as viewed in the so-called anatomic position. This important basic principle of gross anatomy has been ignored for years by those describing the relationships of structures within the heart, these cardiac components usually being described in the setting of the heart removed from the body, and positioned on its apex. With the increasing use in clinical practice of tomographic techniques for diagnosis, in which the heart is viewed as it lies within the body, this conventional approach to description of cardiac structures becomes increasingly confusing. Thus, when the heart is viewed in attitudinally appropriate fashion, with the apex pointing to the left, and with the so-called right heart chambers positioned anteriorly relative to the so-called left counterparts, the current adjectives used for description are found to be wanting. For example, with the heart in the position it occupies during life, the so-called posterior descending coronary artery is seen to be positioned inferiorly relative to the ventricular mass. It is more correct to describe this artery as being inferior and interventricular. Such a change has major clinical significance, since blockage of the artery produces inferior myocardial infarction, the leads used for electrocardiographic recording being placed so as to respect the anatomic position. Another example of the deficiencies of the "Valentine" approach to cardiac description is seen when the mitral valve is viewed in attitudinally appropriate fashion. The papillary muscles supporting the tendinous cords are seen to be located inferiorly and adjacent to the ventricular septum, and superiorly and located on the posterior left ventricular wall when viewed in this fashion. Currently, however, the inferoseptal muscle is described as being posteromedial. Those performing electrophysiological studies of the heart have already appreciated the problems created by assessing the heart in "Valentine" fashion, since when described in this way, a catheter passing upwards through the inferior caval vein is said to progress in an anterior fashion. A committee has recommended use of attitudinally appropriate terminology to avoid these problems. We suggest that those teaching cardiac anatomy in medical schools should also insist on the use of attitudinally appropriate nomenclature when describing the heart, as is currently the case for all other structures in the body. (c) 2008 Wiley-Liss, Inc.