CHAPTER XXXII.
SURGICAL DISEASES OF THE OSSEOUS SYSTEM.

At the outset of a study of surgical diseases of the osseous system it is necessary to emphasize a fact which students and young practitioners are liable to forget, namely, that bone, even the densest, is a tissue, and that as such it is liable to infection, suppuration, gangrene, etc., just as is any other tissue; that all infectious processes are identical in general character, their gross manifestations varying only by virtue of the peculiar characteristics of the tissue in which the infection occurs. Bone is vascular, and even that exceedingly hard variety, which is met with in the petrous portion of the temporal, or the ivory exostosis, has sufficient connection with the vascular system to permit of its proper nutrition. The firmest and hardest bone will bleed when divided or injured, and any tissue which will thus bleed can react injuriously to various irritants.

All bone-marrow begins as red marrow, with 1 or 2 per cent. of fat, and ends by becoming yellow, with 60 or 70 per cent. of fat, and whether this change shall take place suddenly or rapidly depends upon diverse conditions. Many years ago it was claimed by Bourgery that bone is simply a large cavernous arrangement where stagnation of the blood current favors the deposition of fat. Fatty alteration progresses from periphery to centre, and the bones of the hands and feet undergo fatty alterations before those of the trunk and pelvis. In other words, the truncal skeleton remains as “red bone” longer than the balance of the osseous system, and he whose sternum has become a “yellow bone” should have reached a ripe old age. In long bones distal extremities first become fatty. Individual peculiarities seem to govern these changes. Thus the neck of the femur will sometimes be fatty and friable at the fortieth year, or reasonably firm and still red at the eightieth. This fatty condition is not to be confounded with true osteoporosis or rarefaction in bone, though it is often associated with it. When the two conditions are combined we have osteoporosis adiposa. Into this condition immobilized limbs pass more easily than those which are used. Their weeks have been equal to years of ordinary inactivity. Red bone seems to be too highly vascular to be a favorite site for tubercle, and distinctly yellow bone too non-vascular. Consequently bone tuberculosis is less often seen at the extremes of life. White bone, as those who make anatomical preparations call it, is most favorable for tuberculous infection on account of its minimum contents of blood and fat. These bones come from phthisical subjects.

ACUTE OSTEOMYELITIS.

This condition was never accurately recognized until described by Chassaignac, in 1853, and even he missed many of its distinctive features, although he gave to it a most descriptive name, “typhus of the limbs.”

Pathology.

—The disease is a distinctly infectious process, limited sometimes to the bone-marrow and internal portion of the bone, sometimes apparently involving every particle of the osseous structure. Its onset is sudden, its manifestations acute and serious, and its ravages, when not promptly checked, most extensive. The following more or less distinct varieties may be distinguished:

It is known that the virulence of cocci growing under pressure is thereby much enhanced; hence the extreme rapidity of some of these disease processes may be thereby better explained.

PLATE XXXV