Anatomy · Heart & blood vessels

Coronary arteries

The heart's own blood supply

Heart surface · arterial supply

The right and left coronary arteries are the first branches of the aorta, arising from the aortic sinuses just above the aortic valve. They run in the grooves on the surface of the heart, like a crown (Latin corona), and supply the heart muscle itself. The left divides almost at once into the left anterior descending and circumflex arteries.

How to spot them

▸Two vessels from the aortic root, the right and the left, seen on the surface in the atrioventricular and interventricular grooves
▸The left main coronary artery is short and divides into the left anterior descending and circumflex arteries
▸The right coronary artery runs in the right atrioventricular groove and gives the marginal and (usually) posterior descending arteries
▸Accompanied by cardiac veins, which drain to the coronary sinus on the back of the heart

What to know

The first branches of the aorta, arising from the sinuses just above its valve

Coronary arteries — right and left, from the right and left aortic sinuses.

Named from the Latin for 'crown' because they encircle the heart in its grooves

Coronary arteries — corona, 'crown'.

The left anterior descending branch, occlusion of which is nicknamed the 'widowmaker', supplies the front of the left ventricle and most of the septum

Coronary arteries — left anterior descending (interventricular) artery.

A vessel in the right atrioventricular groove that supplies the sinoatrial node in roughly 60% of people and the AV node in about 80%

Coronary arteries — the right coronary artery.

Filling mainly in diastole because contraction of the muscle squeezes their branches shut

Coronary arteries — the left ventricle is perfused chiefly in diastole.

Their 'dominance' depends on which gives off the posterior descending artery, the right in about 70–85% of people

Coronary arteries — right dominance.

Narrowing of these vessels by atheroma causes angina; sudden blockage by a clot causes a heart attack

Coronary arteries — coronary artery disease and myocardial infarction.

Key ideas

Functional end-arteries: collateral channels are few, so sudden occlusion damages the muscle it supplies.
Veins run alongside: great, middle and small cardiac veins drain to the coronary sinus, which opens into the right atrium.

Quick-fire facts

•They arise from the right and left aortic sinuses; the third (posterior, non-coronary) sinus gives no branch.
•The left main stem is typically 1–2 cm long before dividing into the left anterior descending and circumflex arteries.
•The left anterior descending (also the anterior interventricular) artery runs down the front groove toward the apex.
•The circumflex runs in the left atrioventricular groove round the left border to the back.
•The right coronary artery gives the sinoatrial nodal branch in about 60% of people, the right marginal branch and, in right-dominant hearts, the posterior interventricular (descending) artery.
•Right dominance occurs in roughly 70–85% of people; left dominance in about 8–15%; the rest are codominant.
•The heart muscle extracts about 70–75% of the oxygen from the blood, far more than most tissues, so it cannot readily raise extraction under stress.
•Ischaemia due to narrowing gives angina; the standard bypass graft is the great saphenous vein or the internal thoracic artery.

Drill it — 8 cards

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Sources

OpenStax — 19.1 Heart Anatomy — Anatomy and Physiology 2e (coronary circulation)
TeachMeAnatomy — Vasculature of the Heart