Right coronary artery

The right coronary artery (RCA) is one of the two main coronary arteries that supply the heart with oxygenated blood.

Gross anatomy

Origin

It is a branch of the ascending aorta, with its normal origin in the right aortic sinus, just superior to the aortic valve

Course

The RCA courses to the right in the right atrioventricular groove, along the anterior surface to the inferior surface of the heart.

• in people with right dominant circulation (seen in the majority of people), the RCA turns anteriorly at the crus to become the inferior interventricular artery
• in people with left dominant circulation the RCA peters out usually as an acute marginal artery and the inferior interventricular artery usually arises from the left circumflex artery

Branches

• conus artery (in 60%)
• sinoatrial nodal artery (60%)
• acute marginal arteries (designated AM1, 2, etc)
• atrioventicular nodal artery
• terminal branches (in right dominant circulation)
  • inferior interventricular artery also known as the posterior descending artery (PDA)
  • posterior left ventricular branch (PLV, PLB or PLA)
• in left dominant hearts, the RCA usually peters out as an acute marginal branch

Supply

• conus artery: pulmonary outflow tract
• sinus artery: sinoatrial (SA) node
• acute marginal arteries: anterior wall of the right ventricle
• atrioventricular nodal artery: atrioventricular (AV) node
• terminal branches (in right dominant circulation)
  • PDA: inferior wall of the right ventricle and the inferior 1/3 of the interventricular septum (the latter defining coronary dominance)
  • PLV: inferior wall of the left ventricle

Coronary dominance

Most hearts are right dominant where the PDA is supplied by the RCA. However up to 20% of hearts may be left dominant, where the PDA is supplied by the LAD or LCx or codominant, where a single or duplicated PDA is supplied by branches of both the RCA and LAD/LCx.

For a more in depth discussion of coronary dominance, see the article coronary arterial dominance.

Variant anatomy

Variations in origin

• from the aorta at or above the sinotubular junction
• from the left coronary sinus or left coronary artery where the proximal RCA takes a 'malignant' inter-arterial course in which the vessel is prone to extrinsic compression
• in up to 50% of cases there are separate ostia for the RCA and conus artery ² from the sinus or aorta

Variations in branching

• PDA and PLV as terminal branches
• PDA as the only terminal branch (in which the PLV is supplied by the LCx)
• terminates as an acute marginal branch (in left dominant circulations)
• Kugel's artery
  • uncommon proximal branch which communicates with either the left circumflex artery or the distal right coronary artery near the crux

Variations in course

• intra-atrial course (case 1)
• inter-arterial course due to aberrant origin (case 2)
• shepherd’s crook right coronary artery

See also

• congenital coronary artery anomalies