Necrosis

Necrosis (Gr. nekros, 'dead') is a term employed to denote the death or mortification of bone, but often restricted to the cases in which a considerable part of the shaft of a long bone dies, either directly from injury or from violent inflammation, and is enclosed by a layer of new bone; the death of a thin superficial layer which is not enclosed in a shell of new bone being usually termed exfoliation, and the more gradual destruction of cancellous tissue Caries (q.v.). The bones of the lower extremity—the femur and tibia—are those which are most frequently affected by necrosis, but any bone may be the seat of the process. The jawbones, however, very often suffer from it in persons engaged in making lucifer matches, the disease being induced by the pernicious action of the vapour of phosphorus. The more general use of red or amorphous phosphorus for this purpose has rendered necrosis of the jaws much less common. The dead bone, known as the sequestrum, presents a rough appearance, as if worm-eaten. If the membrane investing the bone (the periosteum) remain healthy, it deposits lymph, which speedily ossifies, forming a shell of healthy bone, which completely invests the dead portion. The essential point in the treatment is the removal of the sequestrum, which is too purely a surgical operation to be described in these pages.