Evidence that the myocardium is a continuous helical muscle with one insertion

Abstract

Introduction and objectivesAnatomically, the heart cannot be suspended in the thorax without structural continuity of the heart muscle to pump blood at a speed of 200cm/s with an efficacy that allows ejecting 70% of the left ventricular volume with only 12% shortening of its contractile unit, the sarcomere. The aim of this study was to investigate a) whether the myocardium is a single, continuous, helical muscle; b) the origin and end of the myocardial muscle; and c) the sliding movement between the myocardial segments during ventricular torsion–detorsion. This forces us to think of an antifriction mechanism. MethodsA total of 18 hearts (10 bovine and 8 human) were used for anatomical and histological studies. Histological an histochemical analysis of the samples were performed, using the Alcian Blue technique to confirm hyaluronic acid and its antifriction mechanism. ResultsThe myocardium could be defined as a single, continuous, and helical muscle that is inserted at its origin and end, according to the specimens analyzed, to an osseus-chondroid-tendinous nucleus called cardiac fulcrum, thus limiting the 2 ventricular chambers. Hyaluronic acid was found in the excision planes between the myocardial bundles. ConclusionsThe myocardium in its longitudinal continuity adopts a spiraling spatial configuration, inserted at its end to a nucleus called cardiac fulcrum. The Thebesian veins and hyaluronic acid could have an essential role in the antifriction mechanism, due to the resistance between the sliding myocardial muscle surfaces in their torsion (systole) and detorsion (suction) motions.