OSTEOSCLEROSIS (osteosclerosis; Greek osteon a bone + a sclerosis) — increase in density of bone structures at the expense of an excess osteogenesis. On the volume of damage of a skeleton allocate local, or narrow, widespread and generalized O. Mestny, or limited, to-rogo sometimes call O., sites enostozy, most often develops in areas of the centers of an inflammation, napr, at osteomyelitis, syphilis, sometimes at tuberculosis of bones, around a tumor, etc., forming a demarcation osteosclerotic shaft (reactive O.). The most expressed he is at to an osteoid osteoma (see), in walls of a sequestral box hron, a Brodie's abscess (see. Brody abscess ) or at hron, sclerosing osteomyelitis of Garre (see. Osteomyelitis ). Widespread O. sometimes develops around metastasises in a bone of a breast cancer, a prostate, a lung, at Leri's melocheostosis and is frequent at Pedzhet's disease. Generalized O. meets at system diaphyseal hyperostoses (see. Kamurati-Engelmanna disease ), marble disease (see), and also at osteomyelofibrosis (see), lymphogranulomatosis (see) and fluorosis of bones.
Macroscopically at the expressed O. in a bone division into compact and spongy substance is broken. It becomes homogeneous («elephant»), massive, heavy, however keeps an anatomic form. Despite increase in mass of cortical substance, durability of a bone as a result of O., as a rule, decreases that can bring to patol. to changes. Microscopically in compact substance of a bone find narrowing of vascular channels (fig. 1) in connection with adjournment of neogenic bone substance on their walls. Neogenic bone substance can have various degree of a maturity — from unripe mesh and fibrous and not quite mature fibrous to a mature lamellar bone tissue. In spongy substance thickness of bone plates due to oppositional imposing of bone substance on preexisting increases or formations of new bone plates, decrease interframe spaces. Quite often processes of excess formation of a bone lead to substitution of spongy bone substance a compact bone. Adjournment of a bone tissue can happen also on the periosteal and endosteal surfaces of cortical substance of a diaphysis. Bones at the same time slightly increase in the diameter, there are phenomena of a hyperostosis.
Diagnosis The lake is founded by hl. obr. on results rentgenol, researches of a skeleton, to-rye allow to judge prevalence, character and extent of osteosclerotic changes. Rentgenol, identification of the expressed O. does not cause difficulties — on the roentgenogram the bone gives more dense shadow (fig. 2), the drawing of spongy substance becomes more dense, bone crossbeams are sharply thickened, their number increases. Reinforced cortical substance has an uneven internal contour, the marrowy cavity is narrowed. At the expressed O. the bone throughout can get a compact structure. In differential diagnosis it is necessary to consider that limited consolidations of a shadow of a bone arise in sites of an osteonecrosis, at compression changes, napr, bodies of vertebrae. At O.'s identification on the roentgenogram the great value is attached to a right choice of physics and technology conditions of a X-ray analysis since in the so-called underexposed pictures, and also pictures received by means of too «soft» beams a false impression of the increased intensity of a shadow of a bone is made.
The visual estimate of change of a mineral saturation of a bone according to roentgenograms is possible with an accuracy of 20 — 30%. More exact quantitative results can be received by photometry of optical density of the roentgenogram (see. Rentgenodensitometriya ). Even more exact is definition by method of a computer tomography (see. Tomography computer ) absorbtion coefficient of X-ray bone. Data on process of substitution of mineral connections in a bone tissue at O. can be obtained also with the help radio isotope research (see) with use of radioactive nuclides 85 Sr and phosphates, marked 99m Tc.
See also Bone, pathology .
Bibliography: Lagunova I. G. X-ray semiotics of diseases of a skeleton, M., 1966; The Multivolume guide to pathological anatomy,” under the editorship of A. I. Strukov, t. 5, page 477, 499, M., 1959, t. 6, page 130, M., 1962; Reynberg S.A. Radiodiagnosis of diseases of bones and joints, book 1 — 2, M., 1964; P at and-sh e in and A. E. Private radiodiagnosis of diseases of bones and joints, Kiev, 1967; Arnold W. u. S an d-k ii h 1 e of S. Zur Pathogenese der Kno-chenmarkscirrhose und Osteosklerose, Virchows Arch. path. Anat., Bd 320, S. 37, 1951; Brown T. S. a. Paterson C. Osteosclerosis in myeloma, - J. Bone Jt Surg., v. 55-B, p. '621, 1973; Sherman F., Wilkinson R. Hall J. Reactive sclerosis of a pedicle and spondylolysis in the lumbar spine, ibid., at. 59-A, p. 49, 1977.
G. I. Lavrishcheva; V. V. Kitayev (rents.).