The variations of the direction of the myocardial bundles of the bridges over coronary arteries and branches were studied in relation to the direction of the vessels over which they are found. The investigation was performed on 82 hearts of individuals whose death was accidental and unrelated to cardiac disease. The hearts were obtained from cadavers of individuals of either sex and different racial groups, whose age ranged from 7 to 68 years. The angle between the direction of the musculature and of the vessels may explain why in some cases there is no change in the structure of the "pontine portion" of the wall.