Coronary artery anomalies (anatomy)

There are a number of common variations in the form and distribution of the coronary arteries:

• 'dominant artery':
  • in 50-60%, the right coronary artery is dominant and it supplies the posterior interventricular artery
  • in 10-20%, the left coronary artery is dominant and supplies the posterior interventricular artery
  • in the remainder, the posterior interventricular artery receives contributions from both the left and right coronary arteries
• nodal arteries:
  • the sinuatrial node is supplied by the right coronary artery in 55% of the population and from the left coronary artery in the remaining 45%
  • usually, the atrioventricular node, its bundle and the first part of its distal branches are supplied by the AV nodal artery from the right coronary artery. The anterior interventricular artery supplies the part of the conducting system immediately distal to this. Occasionally, the latter may extend to supply the node.
• rarely, there may be only one coronary artery; its territory is suitably enlarged to cover the areas that would have been supplied by the missing artery
• in 1-2% of hearts, there are accessory coronary arteries e.g. the circumflex artery may arise directly from the left or right coronary sinuses instead of the left coronary artery