Very little has been written on the subject of pathologic fractures. A brief but very good discussion was given by Key and Conwell.1 Pathologic fractures are taken for granted, recognized and forgotten, perhaps justly so. Yet the question often arises whether a pathologic fracture is or is not present and the question must be disposed of before the diagnosis can be satisfactorily settled. Therefore a knowledge of pathologic fractures and of the relative importance of factors in their causation seems to us of sufficient importance to justify a review of such factors.
To this end we, assisted by Drs. Galloway, Dickson, Sawyer and Rhorer, have reviewed the pathologic fractures encountered at the Mayo Clinic from Jan. 1, 1924, to Jan. 1, 1937, a period of thirteen years. We have found records of 660 pathologic fractures encountered in this period. For the purposes of this review we have divided these