Microscopic study of the myocardial bridges over cardiac veins of pigs

Abstract

Aiming to study the myocardial bridges over the cadiac veins on the optic microscope we used 5 pig hearts. The hearts were fixed in 10% formaldehyde for 10 days, embebbed in paraffin and were submitted to 15m histological serial sections. The sections were stained by Azan and Weigert-van Gieson methods.The myocardial bridges were composed by superficial layer of the myocadium. The great cardiac vein and middle cardiac vein showed similar features on their pre-pontine, pontine, and post-pontine segments. The vessel wall was thin. The middle layer of the veins showed structural changes during its subepicardial course: it was fibro-muscular near the cardiac apex and fibro-elastic on its remaing course were also observed. From a morphofunctional point of view these myocardial bridges may be considered an additional factor for the venous return.