Introduction: The presence of a myocardial bridge on the ramus interventricularis anterior can lead to myocardial ischemia and changes in the structure of the vessel wall, especially in the segment proximal to the bridge. Objectives: Examine the wall structure of the ramus interventricularis anterior and estimate the atherosclerosis in its intramyocardial, proximal, and distal segments with an atherosclerosis index. Materials and Methods: Sections of the ramus interventricularis anterior and its branches were prepared at autopsy from 20 hearts with myocardial bridges. Sections stained with hematoxylin-eosin or elastica van Gieson were examined microscopically, and the thickness of the intima and media was determined with ocularmicrometric measuring to establish an atherosclerosis index (a quotient of intima to media thickness). Results: In histopathologic analysis, atherosclerotic changes of varying intensity were present in segments proximal to the myocardial bridge. In contrast, no histopathologic evidence of atherosclerosis was present in any intramyocardial segment, and distal segments had only mild atherosclerotic changes. In agreement with the histopathologic findings, the atherosclerosis index value of the proximal segment of the ramus interventricularis anterior was significantly higher than that of the intramyocardial segment and the distal segment of the artery (p __ampersandsignlt;0.0001), and the highest value was in in the proximal segment, 1.5-2 cm from the entrance into the intramyocardial segment. Conclusion: The presence of a myocardial bridge in the ramus interventricularis anterior is a risk factor for the development of atherosclerotic changes proximal to the entrance of its intramyocardial segment.