title: Myocardial bridges and their relationship to the anterior interventricular branch of the left coronary artery.
abstract: OBJECTIVE
  To analyze the relationship between myocardial bridges and the anterior interventricular branch (anterior descending) of the left coronary artery.
  
  
  METHODS
  The study was carried out with postmortem material, and methods of dissection and observation were used. We assessed the perimeter of the anterior interventricular branch of the left coronary artery using a pachymeter, calculated its proximal and distal diameters in relation to the myocardial bridge, and also its diameter under the myocardial bridge in 30 hearts. We also observed the position of the myocardial bridge in relation to the origin of the anterior interventricular branch.
  
  
  RESULTS
  The diameters of the anterior interventricular branch were as follows: the mean proximal diameter was 2.76+/-0.76 mm; the mean diameter under the myocardial bridge was 2.08+/-0.54 mm; and the mean distal diameter was 1.98+/-0.59 mm. In 33.33% (10/30) of the cases, the diameter of the anterior interventricular branch under the myocardial bridge was lower than the diameter of the anterior interventricular branch distal to the myocardial bridge. In 3.33% (1/30) of the cases, an atherosclerotic plaque was found in the segment under the myocardial bridge. The myocardial bridge was located in the middle third of the anterior interventricular branch in 86.66% (26/30) of the cases.
  
  
  CONCLUSIONS
  Myocardial bridges are more frequently found in the middle third of the anterior interventricular branch of the left coronary artery. The diameter of the anterior interventricular branch of the left coronary artery under the myocardial bridge may be smaller than after the bridge. Myocardial bridges may not provide protection against the formation of atherosclerotic plaque inside the anterior interventricular branch of the left coronary artery.
authors.affiliation: Centro de Ciências Biológicas, UFPE, Recife, PE. vjr@npd.ufpe.br
authors.forename: Vanildo Júnior de Melo
authors.initials: VJ
authors.lastname: Lima
authors.forename: Jennecy Sales
authors.initials: JS
authors.lastname: Cavalcanti
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Tashiro
mesh_terms: D000328:Adult; D003331:Coronary Vessels / Q000033:anatomy & histology*; D005260:Female; D006321:Heart / Q000033:anatomy & histology*; D006352:Heart Ventricles / Q000033:anatomy & histology; D006801:Humans; D008297:Male; D009206:Myocardium