Circumflex artery of heart

At a glance

English

Circumflex artery of heart

Latin (TA2)

Arteria circumflexa cordis

System

Heart

Region

Trunk

Side

Single, on the midline

About the circumflex artery of heart

The circumflex artery, often written LCx, is one of the two terminal branches of the left coronary artery. It leaves the left main stem at a sharp angle, while its partner, the anterior interventricular artery, carries on down the front of the heart. The circumflex instead turns to the left and travels in the coronary sulcus on the left side, the groove that separates the left atrium from the left ventricle.

Following this groove it wraps around the left (obtuse) margin of the heart and passes on to the diaphragmatic surface. How far it goes depends on the pattern of coronary dominance. In most people it stops short of the crux, where the atrioventricular and interventricular grooves meet behind, and the right coronary artery supplies the posterior (inferior) interventricular artery. In a minority the circumflex itself reaches the crux and gives off that artery, which is called a left-dominant circulation. Unusual courses are described, including a circumflex that springs from the right coronary artery.

Its chief branches are the left marginal (obtuse marginal) arteries, which run down the lateral wall of the left ventricle. It also sends branches to the left atrium and contributes to a posterolateral ventricular branch on the back of the ventricle. In a fair share of people it, rather than the right coronary artery, gives the artery to the sinoatrial node.

Its territory is the lateral and posterior wall of the left ventricle, the anterolateral papillary muscle, together with most of the left atrium. The share of the ventricle it feeds is modest in a right-dominant heart and much larger in a left-dominant one, so the effect of a blockage depends strongly on the individual pattern.

Function and supply

Begins at

The left coronary artery, as its leftward terminal branch, beside the start of the anterior interventricular artery.

Ends at

Ends on the diaphragmatic surface of the left ventricle short of the crux, or, in a left-dominant heart, continues as the posterior interventricular artery; gives left marginal and atrial branches.

Function

Supplies the lateral and posterolateral wall of the left ventricle, the anterolateral papillary muscle and most of the left atrium; in some people also the sinoatrial node, and in a left-dominant heart the inferior septum.