Morphogenetic aspects of the septomarginal trabecula in the human heart

Abstract

IntroductionThe septomarginal trabecula is a constant element of the anatomy of the human heart, which connects the interventricular septum and the anterior wall of the right ventricle. Considering the diversity of opinions about the structure and numerous studies suggesting its important role in haemodynamics and conduction of electrical impulses in the heart, we decided to study this element in detail.Material and methodsThe research was conducted on 220 human hearts. Attention was mainly paid to the structure and topography of the trabecula. Its relation to the anterior papillary muscle was also a part of the study.ResultsThe presence of this morphologically diverse element was confirmed in each of the studied hearts. In most cases the trabecula originated from the upper part of the interventricular septum, separating at an angle increasing proportionally to the number of branches of the crista supraventricularis as well as the number of secondary trabeculae. The criteria established for the study, which included the course of the trabecula in the lumen of the right ventricle and its relation to the anterior papillary muscle, let us distinguish 4 types of septomarginal trabecula (I, II, III, IV). The most common was type III, the undivided trabecula, tightly connecting with the anterior papillary muscle.ConclusionsBased on the results of the following study we propose a hypothesis on the genesis of respective parts of the septomarginal trabecula and a plausible sequence of changes they undergo during human ontogenesis and phylogenesis of the primates.

Septomarginal trabecula and anterior papillary muscle in primate hearts: developmental issues

“…Due to difficulties in acquiring the material, it has taken many years to even reach this point. As it has been mentioned, similar analyses of human hearts had been performed previously [9]. Comparing our data with the previous results facilitated the interpretation of some phenomena taking place both during the ontogeny and phylogeny of primates.…”

“…This is demonstrated by the results of studies made on human material, where, apart from the contact location of the anterior papillary muscle in relation to the septomarginal trabecula, partially fused forms were also observed [9].…”

“…Thus, studies on the developmental mechanisms should focus on evaluating the changeability and topography of both elements. The presented material constitutes a continuation of earlier analyses of crista supraventricularis and septomarginal trabecula in human hearts [8,9].…”

“…The comparison of the analyses performed on human and animal material resulted in some interesting observations [9]. In human hearts, type I was rarely observed, being exclusively related to foetal and child hearts, and only with the parietal location of the anterior papillary muscle (Ic).…”

The structure of the vascular system of the septomarginal trabecula in the heart of an adult

“…The hearts, in which no lesions or developmental defects were found macroscopically during the section, came from adults (18-76 years old) of both sexes. The material was divided into 4 morphological types according to the classification suggested by Kosiński et al 1 The analysis was performed on the basis of the observation of the cross-sections of the SMT divided into 10 equal sections (levels) (Fig. 1).…”