part of part of composed primarily of trabecula cardiac muscle tissue cardiac ventricle trabecula carnea The supporting bundles of muscular fibers lining the walls of the ventricles of the heart. trabecula of heart Wikipedia:Trabeculae_carneae EMAPA:18626 Note that WP states they are ventricular, but MP has classes for atrial ventricular carnea. trabeculae carneae cordis ventricular trabecula cardiac trabecula SCTID:118755002 heart trabecula ventricle trabecula carnea UBERON:0002511 columnae carneae FMA:7269 trabeculae carneae MA:0002831 The purpose of the trabeculae carneae is most likely to prevent suction that would occur with a flat surfaced membrane and thus impair the heart's ability to pump efficiently. The trabeculae carneae also serve a similar function to papillary muscles in that their contraction pulls on the chordae tendineae, preventing inversion of the mitral (bicuspid) and tricuspid valves, that is, their bulging towards the atrial chambers, which would lead to subsequent leakage of the blood into the atria. So by the action of papillary muscles on the atrioventricular valves, backflow of the blood from the ventricles into the atria is prevented