Developmental and Generalized Bone Diseases

A STUDY of the literature reveals considerable confusion as regards the classification of these developmental and generalized bone diseases, a confusion increased by the very elaborate and redundant nomenclature. Conditions thought at one time to be individual and distinct entities, have been shown in the light of further knowledge to have common ground either in causation or in the pathology of the bony changes they produce, and it may be possible to classify them etiologically in the same group. On the other hand, conditions totally distinct have been confused by a similarity of nomenclature, while individual writers have also been generous in bestowing new and individual titles on the same condition. To a radiologist, dealing primarily with the shadows of the pathological changes in the bone, additional difficulty arises from the similar appearances shown in the radiograms of conditions of bone of quite different pathology, making the diagnosis from his standpoint alone difficult or perhaps impossible. From time to time further information on these conditions is being elicited, leading us to alter our original ideas and original classification. For these reasons, I have thought it worth while making an attempt to review the present position with regard to these bone conditions, and to try to classifv them in the light of recent research and recenlt theories. It would be impossible to cover the whole field of (levelopmental and generalized bone diseases in a paper such as this, but I have taken several of the most typical conditions. It is likewise impossible to get examples of all these rarer conditionis in one's own work, and I am greatly indebted to Dr. Brailsford of Birmingham and Dr. Duncan White of Edinburgh for the loan of illustrative slides, and also to the former for the privilege of seeing the proof-sheets dealing with this subject of his recent book "The Radiology of Bones and Joinits" while still in the press. The developmental diseases are those in which the growing bone (growing either in cartilage or membrane) is affected. To understand their production we must know something of the method of bone growth. Histologically, as far as I can gather, the growth of cartilage itself is still somewhat of a mystery. Harris has attempted to simplify the analysis of the disorders of bone, and of bone growth, in terms of the three main processes :-(a) Proliferation in cartilage, (b) calcification in cartilage, and (c) actual …