Right fibrous trigone

The right fibrous trigone of the heart is a dense, triangular area of fibrous tissue located at the base of the heart, forming part of the central fibrous skeleton. It is situated between the aortic annulus and the septal leaflet of the tricuspid valve, providing structural continuity between the aortic, mitral, and tricuspid valves. The right fibrous trigone is contiguous with the membranous septum and is a key component of the central fibrous body, which serves as an anchor for the cardiac valves and provides electrical insulation between the atria and ventricles, except at the site of the atrioventricular conduction system.

The right trigonum fibrosum represents the os cordis seen in the heart of some of the larger animals, as the ox and elephant.