Aortic fibrous ring

The aortic fibrous ring (anulus fibrosus aorticus) in the heart is a dense connective tissue ring that surrounds the aortic valve orifice and forms part of the fibrous skeleton of the heart. It provides firm structural support for the attachment of the aortic valve cusps, maintaining the shape and patency of the aortic opening during the cardiac cycle.

This ring is continuous with adjacent fibrous structures, particularly the left and right fibrous trigones and the right fibrous ring, contributing to the formation of the central fibrous body. It also serves as an anchoring site for myocardial fibers and plays a role in the electrical insulation between atrial and ventricular myocardium.

The aortic fibrous ring is not a true anatomic ring but rather a virtual, crown-shaped (coronet-shaped) structure formed by connecting the basal attachment points (nadirs) of the three aortic valve leaflets. Unlike a simple circular ring, the annulus has a three-dimensional, semilunar configuration with the leaflets attaching in a crown-like pattern rather than along a flat plane. Three points on its aortic margin, each of which conforms to the attachments of two adjacent semilunar valvulae of the aortic valve. The projections between the attachments of the septal and right and the septal and left semilunar valvulae are best developed and are composed of hyaline cartilage. Between the points, the margin of the aortic fibrous ring is semilunar so that its scalloped circumference is in the form of three arcs.