All of the following are true about coronary aery, EXCEPT:: (A) Right coronary aery lies in right anterior coronary sulcus, (B) Left anterior descending aery is a branch of left coronary aery, (C) Usually 3 obtuse marginal aeries arise from left coronary aery, (D) In 85% cases posterior descending interventricular aery arises from right coronary aery
Answer is C. Only one obtuse marginal aery(OM1) arise from circumflex branch of left coronary aery. This obtuse marginal branch serve as a boundary between the proximal and distal poion of left circumflex aery(LCx). Poion of left circumflex aery proximal to obtuse marginal aery is called proximal LCx, whereas the segment below OM1 is the distal LCx. Ref: Clinical Anatomy for Medical Students By Richard S snell, 6th Edition, Pages 103-4