Osteomalacia is the term used to describe inadequate osteoid mineralisation in the adult. Stress fractures of the weakened bones are common and the resultant seams of osteoid are known as Looser's zones. This film of the left scapula of a woman with vitamin D deficiency illustrates the typical appearance of a Looser zone. There is little or no evidence of healing. Because Loosers zones are due to stress induced by normal activity they tend to occur at constant symmetrical sites: these include the ribs, the scapulae, the obturator rings of the pelvis, the metatarsal shafts, and the femoral necks (see Fig. 23.69). Osteomalacia results in generalised demineralisation of the bones but this may be evident radiologically only when the disease is severe. When gross osteomalacia is present deformities of the weakened bones may occur these include triradiate pelvis, kyphosis, bowing of the limbs, 'hour-glass' shaped thoracic cage and basilar invagination of the skull.
