This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S., Subject name: Medicine
SA node is supplied by 
Select and explain. 
A. Right coronary artery, B. LAD, C. LCX, D. RAD
A: Right coronary artery
Answer: A: Right coronary artery 
Explanation: Ans. a (Right coronary artery). (Ref. Harrison's Medicine, 18th ed/Chapter 230.)SA NODE# SA node lies at the junction of right atrium and SVC.# It measures 15 mm x 2-3 mm in size.# It is supplied by sinus node artery, which arises from right coronary (60%) or left circumflex coronary artery (40%).AV node# AV node lies at the bases of inter-atrial septum just above the tricuspid annulus and anterior to coronary sinus.# It is supplied by posterior descending coronary artery (90%).Bundle of His# Has dual blood supply (*AV nodal artery + branches of anterior descending coronary artery).