Critical Overview

The surgical anatomy of the aortic root

Cardiac Unit, Institute of Child Health, University College, 30 Guilford Street, London WC1N 1EH, UK

^* Corresponding author: ^* Tel.: +44-171-9052295; fax: +44-171-9052324 E-mail: r.anderson{at}ich.ucl.ac.uk

There is still no consensus on the best way to describe the anatomy of the aortic root. Different surgeons use the term ‘annulus’ to describe different parts of the components of the aortic valve. There is also lack of agreement within the surgical literature with regard to the nature of the ventriculo-aortic junction. In this review, I describe the components of the aortic valve, and its supporting ventricular structures, as seen by the anatomist. The essence of the valvar complex is the semilunar attachments of the valvar leaflets. These extend from their basal attachments within the left ventricle to their distal attachments at the sinutubular junction. The extent of the leaflets defines the length of the root. Within this length, the semilunar lines of attachments of the leaflets cross the anatomic ventriculo-aortic junction, the latter being the circular line marking the transition from ventricular to arterial walls. The posterior part of this line is made up of fibrous continuity between the leaflets of the aortic and mitral valves. Because the semilunar lines of attachment cross this anatomic junction, crescents of ventricular wall are incorporated at the base of each arterial valvar sinus, whilst triangles of arterial wall are incorporated between the zones of apposition of the valvar leaflets as they extend to become attached at the sinutubular junction. The overall, three-dimensional arrangement of the leaflets takes the form of a crown. It is questionable whether this crown is best described as an ‘annulus’, just as it is questionable whether the leaflets should be described as ‘cusps’, or only the peripheral parts of the zones of apposition between the leaflets as the ‘commissures’. Only time, and usage, will answer these questions.

Key Words: Leaflets • Commissures • Annulus • Aortic valve