It consists of fibrous rings (dense and regular connective tissue, a lot of collagen and few elastic fibers) that surround the valve orifices (atrioventricular orifices and orifices that host the semilunar valves) supporting the heart valves ; it also has connective formations that attack myocardial bundles . The space between these four rings is filled with a fibrous connective that forms:
- right fibrous trigone placed between the aortic orifice (aortic valve) and the two atrioventricular orifices (tricuspid and bicuspid valves).
- left fibrous tract placed between the left atrioventricular orifice and the aortic one.
The fibrous ring of the pulmonary orifice does not form the fibrous skeleton but from it originates the tendon that attaches to the right aortic valve flap.
Function of the fibrous skeleton
The fibrous skeleton is a fundamental element as it is at the base of the shape of the heart, since it attaches to the muscular bundles that form the walls of atria and ventricles. It is also at the base of the structure of the heart valves, to which inter alia attack via connective laminae. Another very important function of the fibrous skeleton of the heart is the electrical isolation of atria and ventricles ; it means that the electrical impulse is conducted separately to the atria and ventricles, and is completely under the control of the heart's conduction system .