Light micrograph of human bone stained to demonstrate osteomalacia, or softening of the bones. a condition known as rickets when it occurs in children. The condition may lead to bending of the bones and deformity in adult life. Osteomalacia is caused by a lack of vitamin D, usually due to a poor diet & lack of sunlight. Whilst the action of the bone matrix-generating osteoblast cells (black dots) is unaffected, a delay occurs in the deposition of calcium, the hardener of bone, which leads to an accumulation of unmineralised bone (brown areas). Normal mineralised bone appears green. Undecalcified resin section, Goldner's trichrome stain. References: UMICROCOSMOS u, figure 2.31, page 31.