FIGURE 3.

Schematic diagrams to show how the Fourier transform of the (1,0) and (1,1) reflections interacts with the Ewald sphere in reciprocal space. A cross section of the heart, seen from the top, is shown. At 15 representative points, the (1,0) and (1,1) equatorial reflections, which are two rings in reciprocal space, are calculated according to the fiber orientation predicted by the model of Streeter et al. (1969) and shown in the insets. The direction of the x-ray beam is normal to the drawing, passing at the center. The line in the insets is parallel to the fiber axis. The dark background of the insets is a part of the Ewald sphere, which cuts the rings of equatorial reflections. The cross sections of the rings by the Ewald sphere give rise to the equatorial reflections that we observe in an actual x-ray diffraction experiment. Depending on the orientation of the muscle fiber, the rings of the equatorial reflections change their orientation in the reciprocal space so that reflections are observed at different angles.