Anatomy

Right coronary artery

The RCA travels down the right atrioventricular groove. At the crux of the heart — where the posterior AV groove meets the posterior interventricular groove — the dominant artery gives rise to the posterior descending artery (PDA) and posterolateral branches (PLBs).

Coronary dominance describes which vessel reaches the crux and supplies these inferior territories:

Right-dominant (~70–85% of people): PDA and PLBs arise from the RCA. The most common pattern.
Left-dominant (~5–10%): PDA and PLBs arise from the left circumflex (LCx). Despite the RCA still existing, the LCx does the heavy lifting inferiorly.
Co-dominant (~10–20%): Both the RCA and LCx contribute to posterior supply.

Segments

Click a segment to highlight it in the viewer and pull up its profile.

Picking a view

LAO 45: the workhorse RCA view — the artery is laid out along the right AV groove.
RAO 30: shows the mid RCA and acute marginals; complementary to LAO.
PA / CRA 30: opens the crux and PDA origin — essential before treating distal lesions.

Branches not visualised in the model

Conus branch

The first branch off the RCA, arising just beyond the ostium. It wraps around the right ventricular outflow tract (the pulmonary conus). Occasionally arises directly from the aorta as a separate ostium — easy to mistake for a second RCA when catheterising.

SA nodal branch

Arises from the proximal RCA in ~55–60% of people; in the remaining ~40% it comes off the LCx. Travels superiorly to supply the sinoatrial node. Its origin is the reason proximal RCA or proximal LCx disease can cause sinus node dysfunction.

AV nodal branch

A small but critical branch arising from the dominant artery at or near the crux, supplying the atrioventricular node and proximal His bundle. In right-dominant patients (the majority) this comes from the distal RCA. Occlusion at this level — as in an inferior STEMI — is the anatomical reason for PR prolongation and complete heart block on the 12-lead.