Morphology/Structure
The left fibrous ring consists of a dense connective tissue surrounding the left atrioventricular orifice. It forms part of the left atrioventricular valve.
Using the term anulus is somewhat problematic as they’re not annular in shape and are often discontinuous.
Key Features/Anatomical Relations
The left fibrous ring provides the attachment point for the three left atrioventricular valve leaflets that sit at the junction between the left atrium and ventricle.
The left fibrous ring is connected to the aortic ring by the left fibrous trigone.
Function
The collagen of the fibrous ring helps to separate electrical activities between the chambers by insulating the propagation of electrical impulses during a heartbeat. The left fibrous ring provides structural support and thus competency to the left atrioventricular valve and prevents its over distension. It also provides a direct attachment for cardiac muscle.
List of Clinical Correlates
- Mitral regurgitation
