FIGURE 1.

A simplified drawing model of the fiber orientation of the left ventricle with the right ventricle omitted for interpretation of complex x-ray diffraction patterns. In the epicardium, the fibers are inclined from the vertical z axis, which connects the base and apex. At the middle of the thickness of the wall, the fibers are running in the horizontal plane, and inclined in the opposite direction in the endocardium. The y axis is parallel to the x-ray beam, which runs horizontally. The horizontal section on the top is the “equatorial” plane, where the heart is widest, through which the x-ray beam passes into the heart.