What is the function of pectinate muscles of heart ?
Posted Aug 28 2011 10:27am
Pectinate muscles are specialized Intracardiac muscle
Pectinate muscles are located mainly in the right atrium , more in right atrial appendage , sparse in left atrium
Has muscle fibers arranged in a comb like fashion.
Has less mechanical activity, no significant contribution to atrial contractility.
Can stretch and improve the voluminous nature of right atrium
The pectinate muscle folds act as RA volume reserve during adverse loading conditions . It helps RA dilate with out much wall stress.
Rarely it can be a cell of origin for focal atrial tachycardia
Image Source : Greys anatomy
The concertina like effect of pectinate muscle .
The atrial infolding increases the surface area of atrial chamber at times of dilatation , like the music instrument .So, these macro folds ( like intestinal villi ) help overcome the constantly changing volume status of right atrium.Since the variation left atrial blood flow is not that much , the pectinate muscles are not well developed in the left atrium.
The same rules would apply for why there is excess trabeculations in right ventricle than left ventricle .