Unraveling the anatomy of the cardiac skeleton of the heart (913.6)

Abstract

The fibrous skeleton of the heart is an integral and significant structure, with both supportive and functional significance. Yet, its anatomy has not received much emphasis in literature. This fibrous skeleton has many vital functions within the heart, supporting the valves as well as the myocardium, and insulating the atrioventricular bundle as it courses towards the apex. It is a useful structure in cardiac surgery, providing support for repair and replacement of the heart valves. The paper reviews and correlates the anatomy, embryology and clinical significance of this structure. Dissection of the cardiac skeleton was performed on formalin fixed cadavers. It was found that the aortic root (the portion of the left ventricular outflow tract, supporting the aortic leaflets) which is typically described in terms of an “annulus”, displayed triple semi‐lunar leaflet attachment configuration. Unlike the atrioventricular annuli, the aortic root provides much more complex support for the aortic leaflets than the planar attachments of the mitral and tricuspid leaflets, creating a new understanding of the components of the cardiac skeleton. It has been reported that fibrous support of the cardiac skeleton is not uniform across all the valves. Others have shown it to be concentrated more centrally, seen in the posterior part of the right coronary and non‐coronary cusps. The membranous septum share by these cusps is continuous with the right fibrous trigone, the remaining aortic and pulmonary cusps have muscular anchors. Although less frequent than myocardial, pathology can arise in the fibrous elements of the heart, either during embryological development, or later in life. It is clear that this structure needs to be studied more extensively.