Schematic representation of the most common type of aorto-left ventricular tunnel. The middle figure shows a cross-sectional view at the approximate level of the aortic sinotubular junction. The tunnel passes from the ascending aorta into the tissue plane between the aortic and pulmonary roots. (a') is a longitudinal section across the left ventricular outflow, through the left and right coronary sinuses of Valsalva (plane "a" of the central figure). In this example, the aortic end of the tunnel lies above the ostium of the right coronary artery, while the ventricular end is found within the intercoronary, interleaflet triangle. The position of the aortic opening is variable and may be found anywhere above the left or right coronary sinus, or the intervening commissure. (b') depicts a longitudinal section crossing the noncoronary and right coronary aortic sinuses (line "b" in the central figure). Because the pulmonary valve lies distal to the aortic valve, the tunnel may displace the free-standing, muscular, subpulmonary infundibulum enroute to the left ventricular cavity. It does not, however, pass through any ventricular myocardium.