[Coronary muscle bridge and its relations to local coronary sclerosis, regional myocardial ischemia and coronary spasm. A morphometric study].

Morphometrical investigations on 35 coronary arteries with muscle bridges prove their local protection from atherosclerosis. The average values of the intima thickness in the artery proximally situated to the coronary muscle bridge are 406.6 microns, in the region of the bridge 66.3 microns and distal to the bridge 103.4 microns. The correspondent values of the media are not significant. Stenoses situated proximally to the coronary muscle bridges are almost completely of the eccentric kind and must be considered as potentially dynamic stenoses. The morphological and angiographical findings in cases of coronary muscle bridges, together with clinical observations, indicate a connection between coronary muscle bridges and coronary spasm, at least under pathophysiological conditions.