Anatomy · Heart & blood vessels

Left ventricle

Thickest chamber wall

Heart · systemic pump

The lower left chamber of the heart, which receives oxygenated blood from the left atrium through the mitral valve and ejects it through the aortic valve into the aorta. Its muscular wall, typically about 8–12 mm thick, is roughly three times thicker than the right ventricle's because it must drive blood around the whole body against systemic pressure.

How to spot them

▸Thickest wall of the four chambers, so a circular cross-section in slices of the heart
▸Two large papillary muscles (anterolateral and posteromedial) anchoring chordae tendineae
▸Forms the apex and much of the left border of the heart
▸Inlet through the two-cusped valve, outlet through the smooth-walled aortic vestibule

What to know

The chamber with the thickest wall in the body's central pump, typically 8–12 mm

Left ventricle — it generates systemic blood pressure.

Its wall is about three times thicker than that of the chamber beside it because it works against a much higher pressure

Left ventricle versus right ventricle.

A chamber with just two papillary muscles, anterolateral and posteromedial, tethering the cords of a two-cusped valve

Left ventricle — the right ventricle has three papillary muscles.

Sits between the valve named after a bishop's hat and the valve guarding the body's largest artery

Left ventricle — between the mitral and aortic valves.

The chamber whose ejection fraction, normally about 55–70%, is measured on an echocardiogram

Left ventricle — ejection fraction = stroke volume / end-diastolic volume.

Its downward-pointing tip produces the apex beat felt in the fifth intercostal space

Left ventricle — forms the apex of the heart.

The chamber most often damaged by a blocked left anterior descending artery, the so-called widowmaker

Left ventricle — the LAD supplies the anterior wall and most of the septum.

Key ideas

Wall thickness matches workload: systemic pressure (about 120/80 mmHg) versus pulmonary pressure of roughly 25/8 mmHg.
Unlike most organs, the left ventricle is perfused mainly in diastole, because contraction squeezes its own coronary vessels shut.

Quick-fire facts

•Normal left ventricular wall thickness in diastole is roughly 6–11 mm; sustained overload (hypertension, aortic stenosis) leads to hypertrophy.
•Inlet: mitral (left atrioventricular) valve. Outlet: aortic valve.
•Two papillary muscles: anterolateral and posteromedial; chordae tendineae attach them to the mitral cusps.
•Its inner surface is ridged by trabeculae carneae, but the outflow tract just below the aortic valve is smooth.
•It forms the apex, most of the left border, and much of the diaphragmatic surface of the heart.
•Normal resting stroke volume is about 70 mL; multiplied by heart rate this gives cardiac output of about 5 L/min.
•Ejection fraction below about 40% indicates systolic heart failure.
•Supplied by the left anterior descending and circumflex arteries and, in right-dominant hearts, the posterior descending artery.

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Sources

OpenStax — 19.1 Heart Anatomy — Anatomy and Physiology 2e
TeachMeAnatomy — Atria and Ventricles of the Heart