Radiologic and pathologic analysis of solitary bone lesions. Part II: periosteal reactions.

The activated periosteum has a deceptive anatomic constancy amidst change. The change involves the production of matrix and, in the process, proliferation and expenditure of cells. When the demand for a reaction is excessive, nearby extraperiosteal soft tissue serves as a ready source for additional modulating cells, just as it does for fracture callus. The configuration of a periosteal reaction is an index of the nature and intensity of the inciting process.