The structure and function of the helical heart and its buttress wrapping. II. Interface between unfolded myocardial...

The unfolded myocardial band containing a central fold, extending between the pulmonary artery and aorta, has been used to explain the intact or wrapped cardiac structure, composed of a basal and apical loop forming a buttress and helix, connected to the outflow vessels of both ventricles. The interface between this simple structure, and embryologic development of the primitive heart evolving from a singular tube, into a dual pumping chamber with separate left and right sides, must be explained. The objective is to suggest that a simple and integrated triple figure-eight spiral band, with three S-shaped helixes and their apices may correlate the conventional embryologic development of the primitive heart (bulbus cordis, ventricle, and arterial outflow vessels), with the three stages of spatial orientation of the myocardial band (basal and apical loops), which extends between dual ventricular outflow vessels, in the sequence defined by the unwrapped myocardial band.