Figure 1: Schematic draw illustration which depicts the direction of birefringent tendon collagen fibers with respect to the plane of polarized light (PPL). The birefringence intensity varies as a function of the angle of the fiber orientation with respect to the PPLs of the polarizer (X-axis) and of the analyzer (Y-axis). The Maltese cross image, seen in the tendon cross-section and represented schematically in the upper ellipsoidal diagram, results from the contrast of the birefringence extinction from fibers parallel to the X- or Y-axes (black image), with the birefringence intensity from fibers oriented at 45° (arrows) relative to the X- and Y-axes.