Osteoporosis. Coloured Scanning Electron Microgr- aph (SEM) of the brittle and spongy thigh bone (femur) from a patient with osteoporosis. The lighter areas of this bone have a grainy, spongy appearance with dark areas being where the bone mineral has been reabsorbed by the body. Osteopor- osis, also known as brittle bone disease, is the loss of the protein matrix from bone causing it to become brittle and easily fractured. The condition is seen most commonly in the thigh and back bones of post-menopausal women, where it is associated with a reduction in oestrogen-hormone production. Magnification: x60 at 6x7cmsize. magnificatin: x45 at6x4.5cm size.