Branches of the Right Coronary Artery
The right coronary artery (RCA) typically has 7 major branches in a right-dominant circulation: conus branch, sinoatrial (SA) nodal branch, right ventricular branches, acute marginal branches, posterior descending artery (PDA), posterolateral branches, and posterior descending septal perforators. 1
Main Branches of the RCA
According to the American College of Cardiology/American Heart Association guidelines, the right coronary artery branches include:
- Conus Branch - First branch, supplies the right ventricular outflow tract
- Sinoatrial (SA) Nodal Branch - Supplies the SA node (in approximately 85% of people)
- Right Ventricular Branches - Supply the right ventricular wall
- Acute Marginal Branches - Supply the right ventricular free wall
- Posterior Descending Artery (PDA) - Runs in the posterior interventricular groove and supplies septal perforator branches (in right-dominant circulation)
- Posterolateral Branches - Can include up to three branches:
- First right posterolateral branch
- Second right posterolateral branch
- Third right posterolateral branch
- Posterior Descending Septal Perforators - Arise from the PDA to supply the interventricular septum
Anatomical Variations
The branching pattern of the RCA can vary based on coronary dominance:
- Right Dominance (85% of population): The RCA gives rise to the PDA and posterolateral branches
- Left Dominance (10-15%): The PDA arises from the left circumflex artery
- Co-dominance: The RCA supplies the PDA, and the left circumflex supplies the posterolateral branches 1, 2
Clinical Significance
Understanding RCA anatomy is crucial for:
- Accurate interpretation of coronary angiography and CT imaging
- Proper planning of coronary interventions
- Recognizing potential areas of ischemia in acute coronary syndromes
- Avoiding complications during cardiac surgery
Rare Variations
Rare variations in RCA anatomy have been reported, including:
- Double right coronary artery with two separate ostia 3, 4
- Anomalous origin of the SA nodal artery from the posterolateral branch of the RCA (0.8% of cases) 5
- Single right coronary artery supplying the entire heart 6
These variations, while uncommon, can have important implications for coronary interventions and cardiac surgery.
Conclusion
Knowledge of the normal branching pattern of the RCA and its potential variations is essential for accurate diagnosis and management of coronary artery disease, as well as for planning coronary interventions and cardiac surgery.