[Architectonic of the working myocardium fibers in pig cardiac ventricles].

Architecture of the working myocardium fibers in pig cardiac ventricles was studied using the method of layer-by-layer splitting of muscle bundles. It was shown that the muscle fiber bundles in both ventricles were arranged in three directions. Three layers of fibers were distinguished as superficial, middle and deep. The fibers of the superficial layer follow a spiral course. In the apex cordis, muscle fiber bundles penetrate deep into myocardium, giving rise to the fibers of the deep layer. Middle layer in both cardiac ventricles is represented by the ring fibers, which are absent in the apex of both right and left ventricle. Fiber orientation was found to change depending on the depth of their location and was different in both ventricles. Fibers of the deep layer in the right ventricle are arranged obliquely on the free wall, while in the interventricular septum they are directed towards apico-basal cardiac axis. In the left ventricle, fibers of the deep layer are situated spirally from the apex to the base of the heart.