Left ventricle

Antoine Micheau

The left ventricle is the thickest and most muscular chamber of the heart, responsible for pumping oxygenated blood into the systemic circulation via the aorta. Its anatomy can be described in terms of shape, walls, internal structures, and outflow components.

General morphology

The left ventricle has a conical shape with the apex of the heart formed by its tip. It is smaller in volume than the right ventricle but has a much thicker wall (about 8–15 mm) due to the high pressure required for systemic circulation.

Walls and surfaces

Anterior wall (superior wall): contiguous with the left atrium and right ventricle.
Posterior wall (inferior wall): adjacent to the diaphragm.
Septal wall: formed by the interventricular septum separating it from the right ventricle.
Lateral wall: faces the left lung.

Internal structures

Mitral valve orifice: located at the base of the ventricle, connecting it to the left atrium.
Papillary muscles: usually two (superior and inferior), larger and more robust than those in the right ventricle, anchoring the mitral valve leaflets via chordae tendineae.
Trabeculae carneae: finer and more numerous than in the right ventricle, lining the inner wall.
Interventricular septum: muscular and bulging into the right ventricle, contributing to left ventricular contraction.

Outflow tract

The left ventricular outflow tract leads into the aortic valve, which has three semilunar cusps (right, left, and posterior). The smooth-walled outflow portion (aortic vestibule) lies anterior and superior to the mitral orifice, forming the continuity between the anterior mitral leaflet and the aortic root (the aortomitral continuity).

Functional aspects

During systole, the coordinated contraction of the ventricular wall, septum, and papillary muscles ensures effective ejection of blood through the aortic valve. The left ventricle generates higher pressures compared to the right ventricle, making its muscular wall significantly thicker.

Vascular supply

The left ventricle receives blood supply mainly from the left coronary artery branches: the left anterior descending (LAD) artery supplies the anterior wall and septum, and the circumflex artery supplies the lateral and posterior walls. The right coronary artery may contribute to the posterior wall in right-dominant circulation.