The aortic opening is a circular aperture, in front and to the right of the atrioventricular

Atrioventricular

Atrioventricular can refer to:*Left atrioventricular opening*Atrioventricular fistula*Atrioventricular node*The term "Atrioventricular valves" is used to describe the mitral valve and tricuspid valve....

, from which it is separated by the anterior cusp of the bicuspid valve.

Its orifice is guarded by the aortic semilunar valves.

The portion of the ventricle immediately below the aortic orifice is termed the aortic vestibule

Aortic vestibule

The portion of the left ventricle immediately inferior to the aortic orifice is termed the aortic vestibule, and possesses fibrous instead of muscular walls....

, and possesses fibrous instead of muscular walls.