Illustrations of BM reticulin fibers and osteosclerosis. MF-0: scattered linear reticulin fibers with no intersections (internal control is represented by the reticulin fiber around the vessel; MF-1: loose network of reticulin fibers with many intersections, especially in perivascular areas; MF-2: diffuse and dense increase in reticulin fibers, with extensive intersections and occasionally with focal bundles of collagen (arrows); and MF-3: diffuse and dense increase in reticulin fibers, with extensive intersections and coarse bundles of collagen (arrows).