A 67 year-old female, presented with an absent right coronary artery during dissection in the Gross Anatomy Laboratory, Ross University School of Medicine. This is a previously undocumented origin of the right anterior atrial artery and a unique origin of the sinu-atrial node artery. Although the absence of the right coronary artery is rare, with an autopsy occurrence rate of 0.29%, it is extensively documented and not the novelty in this case. The more significant variation is the unusual origin of the right anterior atrial artery and the artery to the sinu-atrial node. Previous studies indicate the artery to the sinu-atrial node arises from the right coronary artery in 54% of the population. In this instance, however, the artery to the sinu-atrial node originates from the right anterior atrial artery which arises directly from the aorta over the right cusp, an origin, which has not been previously documented. Knowledge of the coronary anatomy is important in the understanding of clinical symptoms and in order for successful cardiac surgery to be performed. It is essential, therefore, for this previously undocumented variant to be put forward to raise knowledge of this very unique variation.
