Sinoatrial nodal artery

Branch

Arises from the proximal RCA in about 60% and from the proximal circumflex in about 40%, then runs up the right atrium to the SA node at the junction of the superior vena cava and right atrium.

Traced from the start

  1. Right (anterior) aortic sinus
  2. Left (posterior) aortic sinus and left main stem
  3. Right coronary arteryLeft circumflex artery
  4. Sinoatrial nodal artery

Detail

Origin
RCA 60%, circumflex 40%
Supplies
SA node and the surrounding atrial myocardium

When it goes wrong

Occlusion of the RCA proximal to the SA nodal branch

Sinus bradycardia or sinus arrest in inferior MI, compounded by vagal activation (Bezold-Jarisch reflex)

Practise this structure

2 questions in the bank tagged Cardiac Conduction.