Variations in the papillary muscles of normal tricuspid valve and their clinical relevance in medicolegal autopsies

OBJECTIVE: In our study, tricuspid valves in cases of sudden death secondary to congenital differences of the tricuspid valve with significant papillary muscle anatomy were investigated. No studies of papillary muscle anatomy of the tricuspid valve have been found in medicolegal autopsies in literature. The purpose of our study is to investigate the relationship of papillary muscle in tricuspid valve in cases of sudden deaths, especially those resulting from cardiac disease, with the muscle structure, as well as the number of the muscle leading congenital changes.

METHODS: The study was carried out in the Department of Anatomy, Faculty of Medicine, Ege, University, Izmir, Turkey and comprised of 400 human hearts obtained between 2000 and 2002 from 400 autopsy cases during a medicolegal autopsy with permission from the Council of Forensic Medicine, Izmir. Quantitative and morphological aspects of the papillary muscles of the right ventricle were evaluated. The criteria such as number, incidence, length and shape of the anterior, (APM) septal (SPM) and posterior papillary muscles (PPM) have been observed.

RESULTS: Although the papillary muscle presented great variability in numbers, with a minimum of 2 and a maximum of 9 papillary muscles in the right ventricle, there were usually 3 papillary muscles in the right ventricle; APM, PPM and SPM. The one headed APM was found to be more often in cardiac deaths. However, observing more frequent conical and flat topped configurations in all PPM was striking. The absence or lower ratio, or both of attachment bridges of SPM and APM/PPM in deaths of cardiac origin is also significant. We have found that the presence of this attachment is higher in deaths of noncardiac origin.

CONCLUSION: This anatomical study may explain the increased in incidence wide variations of papillary muscle tricuspid valve in deaths of cardiac origin. The verdict in legal affairs may change with this. The knowledge regarding wide variations and minor anatomical abnormalities of papillary muscle helps forensic examiners not to get confused at unexpected deaths.