BONE, INFLAMMATION OF.—As explained in the INTRODUCTORY CHAPTERS, the bone consists of three parts :, the compact bone-mass, the periosteum, and the bone-marrow. Inflammation may involve any one of these parts, and is then designated accordingly ; or, as is usually the case, all three parts may be affected by a severe inflammation. • Acute inflammation of a bone is generally characterised by a sudden rise in temperature, with violent pain in the affected hone. A swelling of the soft parts covering the bone soon develops, indicating the beginning of an accumulation of pus in or about the bone. As the skin, muscles, tendons, and periosteum which bar the pus from reaching the outer parts are strong and thick, it gets to the surface very slowly ; and, on account of the great tension under which it is put, it causes severe pain. Absorption also takes place, giving rise to the fever.
The inflammation generally produces a purulent affection of the perios teum, varying in extent ; and this in turn causes the destruction of a part of the compact bone-mass, which is deprived of nutrition coming through the blood-vessels of the periosteum. The mortified piece of bone (sequestrum) gradually becomes detached from the unaffected parts, and is cast off. The opening of the abscess and the discharge of the pus do not, as a rule, ter minate the morbid process, and the mortified piece of bone may remain behind for several months. The discharging pus generally causes a fistula, which
remains open until the sequestrum is fully thrown off. At times, however, the dead bone fragment is so large that it cannot pass out through the narrow opening of the fistula ; and as it would require a long time for the sequestrum to be disintegrated and discharged, it is better surgery in such cases to remove the diseased part of the bone by operation. In this way suppuration, which is harmful to the general condition of the patient, is arrested as early as possible. Acute inflammation of bone (osteomyelitis) is more common in children than in adults.
Chronic inflammation in the bone is generally due to tuberculosis ; it develops much more slowly and insidiously, and accumulations of pus are formed mostly without acute pains or high fever. The duration of the disease is also much longer ; it may extend over years, or it may even be altogether incurable. As the destructive process advances step by step, continually involving new parts of the bone, the prospects of cure are much more unfavourable than in the acute form. Hence, in these cases operation should likewise be performed as early as possible, and the diseased portion entirely removed. Chronic hip-joint disease and chronic humpback are diseases of this kind. They are types of localised bone tuberculosis.