Conus Artery

arteria coni arteriosi

The conus artery (conus branch) is the first branch of the right coronary artery, arising at or just after its ostium to supply the right ventricular outflow tract (RVOT, pulmonary conus). It is present as a separate ostium from the aorta in approximately 50% of individuals (third coronary ostium). When arising from the proximal RCA, it provides a collateral route to the anterior descending territory via Vieussens ring.

Region: Chest

Clinical Relevance

Clinical Notes

The conus artery is important for two reasons: its separate ostial origin (present in half the population) means inadvertent cannulation during RCA angiography can cause RVOT contrast filling and confusion; and its anastomosis with the LAD via the Vieussens arterial ring provides a collateral pathway that can supply the anterior wall in proximal LAD occlusion. Isolated conus artery occlusion is rare but can cause RVOT ischaemia, particularly in athletic individuals with high RVOT oxygen demand.

Pathology

Common Injuries & Conditions

Conus Artery as Collateral in LAD Occlusion

In proximal LAD occlusion, the conus artery anastomoses with the LAD via the Vieussens ring, providing early collateral filling to the anterior wall visible on angiography as retrograde LAD opacification from the RCA; this collateral limits infarct size and explains why some proximal LAD occlusions produce smaller than expected anterior MIs.