The development of parosteal bone within muscle following trauma has become an important and interesting surgical problem since the advent of the roentgen ray, which has made more certain the diagnosis of the condition, and the increasing incidence of injuries due to occupation. The intense interest in this condition resulted from the increasing demands made by accident insurance companies upon the surgeon for a more definite prognosis following injury to muscle and bone, because of the workmen's compensation law. Josephson,1 in 1874, made the first collection from the literature of fifty-eight cases of what he called muscular osteomas, and Cahier,2 in 1904, gathered 133 cases. Schulz,3 1903, gathered 296 and, in 1912, Jones and Morgan4 collected 339 cases. During the last decade the recorded cases have numbered in the thousands. All the theories of traumatic bone formation in muscle include the factor of initial injury. In