Modern surgery, general and operative . ause of is most frequently met -n-ith in the diaphyses of the long bones, cariesin the cancellous tissue of bones. The ribs may become carious, but ver\- rarelybecome necrotic. A sequestrum may, but does not often, form in a vertebralbody, in the cancellous head of a long bone, in the carpus, or in the tarsus. If asequestrum arises from tuberculous osteomyehtis it is seldom found completelydetached, but still retains some vascular connection. In tuberculous osteo-myelitis of a long bone the sequestrum is wedge shaped with its base towar
Modern surgery, general and operative . ause of is most frequently met -n-ith in the diaphyses of the long bones, cariesin the cancellous tissue of bones. The ribs may become carious, but ver\- rarelybecome necrotic. A sequestrum may, but does not often, form in a vertebralbody, in the cancellous head of a long bone, in the carpus, or in the tarsus. If asequestrum arises from tuberculous osteomyehtis it is seldom found completelydetached, but still retains some vascular connection. In tuberculous osteo-myelitis of a long bone the sequestrum is wedge shaped with its base towardthe joint, and is due to infarction of terminal arteries. A fragment of deadbone is a foreign body; the healthy bone adjacent to it inflames and softens;granulations form, and this line of granulation, like the line of demarcation ofgangrene, tends to separate the dead part from the living, the white dead bonebeing surrounded by the red zone of granulation tissue. A bit of dead bone is 500 Diseases and Injuries of the Bones and Joints. Fig. 251.—Diagram illustrating the formation of a se-questrum: A, A, Sound bone; B, B, new bone; C, C, granu-lations lining involucrum; D, cloaca; E, sequestrum. called a sequestrum, and Nature tries to cast it off. A superficial sequestrum isknown as an exfoliation. Natures method of casting off a sequestrum is as follows: Suppurationtakes place at the line of demarcation, osteitis extends for a considerabledistance around this line, the periosteum shares in the inflammation, andnew bone forms. A cavity is made within by suppuration, and a box orcase is formed without by ossification, the now entirely loosened sequestrumbeing so encased that it cannot escape. The pus finds its way through the new bone, and there is pre-sented the condition so oftenseen by the surgeon—namely, a case of new boneknown as the involucrum,a cavity containing pus andthe dead fragment or se-questrum, and a discharg-ing sinus or cloaca (). Nature may eventu-a
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Keywords: ., bookcentury1900, bookdecade1910, bookpublishe, booksubjectsurgery
