Short note on left coronary artery

Short note on left coronary artery 

Aortic sinus :It arises from left posterior  aortic sinus of ascending aorta

Size: Bigger than the right coronary artery

Course

1.       It runs forwards and to the left between the pulmonary trunk and left auricle

2.       Then it  divides into anterior interventricular branch and circumflex branch

3.       The anterior inter-ventricular branches of left coronary artery descend downward along the anterior inter-ventricular groove and anastomosis with posterior inter-ventricular branch of left coronary artery

4.       The circumflex branch cross the left border of heart

5.       It then passes along the left posterior part of atrioventricular groove

6.       Then it anastomosis with branch of right coronary artery just left of the crux of heart
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Branches

1.       Anterior interventricular artery: it supplies anterior part of interventricular septum , greater part of the left ventricle and part of right ventricle and a part of left bundle branch of His  

2.       Circumflex artery : it gives a left marginal artery that supplies the left margin of the left ventricle up to the apex of the heart

3.       Diagonal artery: it may arise directly from the trunk of the left coronary artery  

4.       Conus artery : it supplies the pulmonary conus

5.       Atrial branches: they supply the left atrium

Distribution

It supplies :

1.       Most of the left atrium

2.       Most of the left ventricle except a strip along the posterior and inferior surfaces of the heart posterior and inferior surfaces of the heart

3.       Anterior superior 2/3 of the ventricular septum

Coronary dominance

10% individuals are left coronary dominance. It means ventricular septum is supply only by left coronary artery.

posterior inferior part of 1/3 of ventricular septum is  supply by circumflex branch of  branch of left coronary artery

anterior superior part of 2/3 of ventricular septum is supply by anterior interventricular branch of left coronary artery