Figure 1

(A) . A 3D image of normal cartilage (ICRS grade 0, shown in Fig. 1( E ) from a cow femoral head at a lower magnification view using digital zooming shows more clearly that the structure of the interwoven collagen bundles (ICB) near the articular surface (the arrows in Fig 1( A )). (B). A 3D image of normal cartilage from a cow femoral condyle at a higher magnification view using digital zooming shows more clearly the orientation of the collagen fibres in the superficial zone, which is align predominantly in a spatial direction oblique the AC surface. (C): MBI reconstructed from the top eight of 2D images in Fig 1(A) shows clearly the interwoven collagen bundles near the articular surface. (D): The MBI reconstructed from the image stack used to reconstruct the 3D image in Fig 1(B) is analogous to an en face 2D observation, by which the collagen fibres in the superficial zone appear to align predominantly in a direction parallel to the AC surface in 2D images. (E): The corresponding traditional histology of a cow femoral condyle used for ICRS grading shows proteoglycans (blue) are highly deposited in normal cartilage.