Right coronary artery

Structure

The right coronary artery originates above the right aortic sinus above the aortic valve. It passes along the right coronary sulcus (right atrioventricular groove) towards the crux of the heart.

Segments

• Proximal: starting at RCA origin, spanning half the distance to the acute margin
• Middle: from proximal segment to the acute margin
• Distal: from middle segment to origination point of the posterior interventricular artery, where the posterior interventricular sulcus meets the atrioventricular groove on the base of the heart.

Variation

In approximately 80% of patients (right dominant), the RCA gives off the posterior descending artery (PDA). In the other 20%, of cases (left dominant or codominant), the PDA arises from the left circumflex artery or is supplied by both the right coronary artery and the left circumflex. The PDA supplies the inferior wall, ventricular septum, and the posteromedial papillary muscle.

The RCA also supplies the SA nodal artery in 60% of people. The other 40% of the time, the SA nodal artery is supplied by the left circumflex artery.

Although rare, several anomalous courses of the right coronary artery have been described including origin from the left aortic sinus.

Distribution

The right coronary artery supplies oxygenated blood to the right atrium, the right ventricle, and the posterior third and inferior end of the interventricular septum. It may also supply 25% to 35% of the left ventricle (LV).

There is significant overlap of supply of the coronary arteries. The right coronary artery is dominant over the left coronary artery 50% of the time, equal to it 20% of the time, and less significant than it 30% of the time.