Bone Destruction not Demonstrable by Radiography

Bones may be the site of neoplastic or inflammatory processes which may either involve the marrow spaces only, or may destroy actual bony trabeculæ. New bone formation is not being considered in this communication. When the process merely substitutes inflammatory or neoplastic cells for marrow cells, no changes demonstrable by radiographic methods are to be expected. This accounts for the presence of secondary deposits seen at post-mortem, in which no change can be seen radiographically even when slices of bone are X rayed. This point has been well demonstrated by Shackman and Harrison (1948). If bone is destroyed, however, it does not seem to be generally realised how large an amount may be destroyed in certain situations without being radiographically detectable. The following experiments were designed to give information on this point. Two normal vertebræ were removed from the lumbar region, post mortem, and radiographed with all the usual aids to produce good definition. A hole 3 mm. (⅛ in.) in diameter was drilled vertically through the centre of the vertebral bodies. The vertebræ were then radiographed in the anteroposterior and lateral projections (Fig. 1a). The air containing hole is well seen in the lateral projection, but is not visible in the antero-posterior projection where it is obscured by the spinus process. The hole was then filled with water (as an approximation to soft tissue) and plugged at each end with plasticine to prevent the water running out.