Papillary muscles and chordae tendineae

Musculi papillares; chordae tendineae

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What it is

Finger-like muscles projecting from the ventricular walls (two in the left ventricle, three in the right) whose tips send fine tendinous cords to the edges of the mitral and tricuspid leaflets.

Function

Contract with the ventricle and keep the leaflets from turning inside-out (prolapsing) into the atria during systole.

Size

Papillary muscles 1.5–3 cm long; chordae tendineae ~0.5–1 mm thick, 1–2 cm long.

Clinical note

Rupture of a papillary muscle after a heart attack causes sudden severe mitral regurgitation; the chordae are nicknamed the "heart strings".