Vessels of the Right Coronary Artery (RCA)
The Right Coronary Artery (RCA) consists of three main segments (proximal, middle, and distal) and gives off several important branches including the posterior descending artery (PDA) and the posterior left ventricular branch (PLVB).
Anatomical Segments of the RCA
The RCA can be divided into three main segments:
Proximal RCA segment
- Originates from the right coronary sinus of the aorta
- Typically gives rise to the conus branch (first branch)
- Often gives rise to the sinoatrial (SA) nodal branch
Middle RCA segment
- Runs in the right atrioventricular groove
- Gives off acute marginal branches to the right ventricle
- Provides right ventricular branches
Distal RCA segment
- Continues in the posterior atrioventricular groove
- Terminates by bifurcating into the posterior descending artery and posterior left ventricular branch
Key Branches of the RCA
- Conus Branch: First branch of the RCA that supplies the right ventricular outflow tract
- Sinoatrial (SA) Nodal Artery: Supplies the SA node (in approximately 60% of cases)
- Right Ventricular Branches: Multiple branches supplying the right ventricle
- Acute Marginal Branches: Supply the lateral wall of the right ventricle
- Posterior Descending Artery (PDA): In right-dominant circulation (most common), arises from the distal RCA and supplies the posterior third of the interventricular septum
- Posterior Left Ventricular Branch (PLVB): Supplies the posterior wall of the left ventricle
Clinical Significance
Understanding the anatomy of the RCA and its branches is crucial for:
- Accurate interpretation of coronary imaging studies
- Identification of coronary anomalies that may affect cardiac function
- Localization of coronary lesions during interventional procedures
- Assessment of coronary artery disease impact on cardiac function
Imaging Considerations
When visualizing the RCA and its branches on echocardiography, specific views are required 1:
- Proximal RCA: Best seen in precordial short axis at level of aortic valve, precordial long axis (inferior tangential), subcostal coronal projection of right ventricular outflow tract, and subcostal short axis at level of atrioventricular groove
- Middle RCA: Best seen in precordial long axis (inferior tangential), apical 4-chamber, subcostal left ventricular long axis, and subcostal short axis at level of atrioventricular groove
- Distal RCA: Best seen in apical 4-chamber (inferior) and subcostal atrial long axis (inferior)
- Posterior Descending Artery: Best seen in apical 4-chamber (inferior), subcostal atrial long axis (inferior), and precordial long axis (inferior tangential) imaging
Proper identification and assessment of these vessels are essential for evaluating coronary artery disease and its potential impact on morbidity and mortality.