Osteomyelitis is an inflammation of the marrow and adjacent osseous tissue of a bone. Usually the inflammatory process is widespread, tending to involve the entire marrow cavity, the process, as a rule, being very destructive with extensive secondary necrosis of the bone. Of the jaws, the upper jaw, on account of its protected position, the peculiarities of its vascular supply and the absence of any true marrow cavity is so free from this disease, that osteomyelitis of the lower jaw, only will be considered. While the lower jaw has no distinct marrow cavity as compared with one of the long bones, it has a central nutrient canal containing the inferior dental nerves and vessels, adjacent cancellous tissue, which largely disappears near the symphysis, all enclosed by firm, dense walls of compact bone surmounted by soft cancellous bone forming the alveolar portion. An inflammatory process within the body of the lower