II. Radiological Changes Associated with Certain Metabolic Bone Diseases

The imposing title of this symposium covers a very large subject and we can consider here only certain aspects of metabolic bone disease. The title, naturally, excludes tumours of bone, infections and localised idiopathic bone diseases, such as Paget's disease and fibrous dysplasia. Strictly speaking it should include not only hormone diseases, such as hypo- and hyperparathyroidism, Cushing's syndrome, etc., where the bone changes are undoubtedly of metabolic origin, but also hereditary bone diseases, such as the osteochondrodystrophies, since our present faith is that all genetic disease is based on biochemical abnormalities. We have to leave most of these out, however, for reasons of time. Fortunately, this curtailment is not too serious as the bone changes are of minor importance from the point of view of diagnosis, which can usually be made on purely clinical grounds. The diseases on which we shall concentrate are those which are not easily diagnosed clinically and in the detection of which we have to rely largely on radiological and biochemical findings. These diseases are generalised osteoporosis, with its widely differing aetiology; rickets and osteomalacia; and primary and secondary hyperparathyroidism, which also involves us in the difficult problem of renal osteodystrophy or renal rickets. While discussing these particular diseases, we shall try and emphasise those facets which have a more practical importance and in which knowledge has recently been increased.