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

BACKGROUND: In cardiology, the paths of the arteries penetrating the septomarginal trabecula (SMT) are especially important. They provide blood supply to the apparatus of the right atrioventricular orifice and often form anastomoses with the system of the right coronary artery. Despite this, only a few publications discuss the morphological aspect of the septomarginal trabecula, and available histological analyses seldom deal with its blood supply.

OBJECTIVES: The aim of this study was to analyze the vessel structure of the septomarginal trabecula in terms of the variability of the area of the cross-section of the lumen and the muscular layer of the artery.

MATERIAL AND METHODS: The study was carried out on the material of 50 human hearts from adults of both sexes. The material was divided into 4 morphological types. Histological examinations were conducted by means of classic staining methods.

RESULTS: At the initial cross-section of the septomarginal trabecula, the area of the cross-section increased to half of the length of the trabecula, and then it started to decrease. This is connected with the thickening of the inner muscular layer of the artery, which proportionally takes up more area of the cross-section of the whole artery of the SMT. The total area of the cross-section of all vessels in both types examined was also the largest in the middle part of the SMT. Furthermore, the results of this study confirm the presence of a connection between both systems of coronary arteries.

CONCLUSIONS: As the septomarginal trabecula passes through the lumen of the right ventricle, its arteries become exposed to the influence of the factors which may evoke a biological response from the walls of this vessel, causing the thickening of the muscular layer and, as a result, of the section of the whole artery, in particular its middle part.