Overview

Each chorda has a core of collagen (mainly type I) with some elastin, covered by endocardium. There are three orders. First-order (marginal) chordae attach to the free edge of a cusp, preventing prolapse and setting where the cusps meet. Second-order (basal or strut) chordae attach to the ventricular surface of the cusps. They carry more load and help keep the ventricle in shape. Third-order chordae run from the ventricular wall to the base of the posterior mitral leaflet.

Each papillary muscle sends chordae to the neighbouring halves of two cusps, so when it contracts it pulls the two cusps together.

Location: Inside the right and left ventricles, between the papillary muscles (or the ventricular wall) and the AV valve cusps.

Anatomy

Histology: Dense regular collagen core covered by endothelium. The chordae contain no muscle and no blood vessels.

Function

Transmit tension from the papillary muscles to the AV valve cusps.
Prevent the cusps from everting (prolapsing) into the atria during ventricular systole.
Maintain the continuity between ventricle and valve that preserves left ventricular shape.

Clinical significance

Chordal rupture (flail leaflet)

Chordae can rupture because of myxomatous degeneration (mitral valve prolapse), infective endocarditis or trauma. The leaflet then flails, causing sudden or worsening mitral regurgitation. Surgeons often repair the valve with artificial chordae made of ePTFE rather than replacing it.

Rheumatic heart disease

In rheumatic heart disease, the chordae thicken, shorten and fuse. Together with fusion of the commissures, this produces the "fish-mouth" stenotic mitral valve.

Compiled from standard anatomy and physiology references — see the Cardiovascular System sources. For education only; not medical advice.