8.6. Fibrous Skeleton of the Heart
A fibrous ‘cardiac skeleton’ supports the four valves of the heart, as shown in the accompanying diagram. Note how this structure is composed of a central fibrous body with left and right ‘fibrous trigones’. The trigones are connected to the central body but also to the tricuspid and bicuspid rings (sometimes called annuli) which surround the valves and contribute to their strength. Fibrous rings also extend from the central body to support the aortic and pulmonary valves.