Ostitis

OSTITIS (from the Greek osteon - bone), in the proper sense of the word, means such an inflammation of the bone marrow that occurs in areas of the bone rich in spongy substance (short bones, flat bones, metaphyses of long bones) and in which, consequently, the bone substance itself is widely involved in the process. Such inflammations can be either acute or chronic. The former are always purulent in character and represent nothing other than purulent osteomyelitis (see) of the corresponding parts of the skeleton with all its inherent characteristic features and consequences. If such a process, which happens very often, passes through the vascular channels of the cortex to the outer periosteum, it is called osteoperiostitis (see), and with the necrosis of the cortex itself - panostitis. Chronic ostitis is much more diverse than acute, and according to the particular character of the main pathological-anatomic changes of the bone observed in them, it is divided into two large groups: rarefying and ossifying ostitis. - R a r e f y i n g ostitis (ostitis rareficiens) (otherwise called inflammatory osteoporosis) occurs during the development in the bone marrow spaces of granulation tissue, which always, as it grows, gradually destroys the bone trabeculae adjacent to it. Such granulations can occasionally develop under the influence of banal pyogenic microbes in sluggish chronic osteomyelitis, acquiring a proliferative rather than a purulent character due to the weakening of the virus or a change in the reactive properties of the organism. But most often in these cases the etiological factor is some specific infection (tuberculosis, syphilis, leprosy, etc.), and the granulation tissue also acquires the corresponding characteristic features. With the progressive development of granulations and the gradual destruction of more and more areas of bone substance, it is called caries. - Ossifying ostitis (ostitis ossificans) - otherwise inflammatory osteosclerosis (see) - arises either as an outcome of rarefying ostitis by scarring of granulations with subsequent metaplasia of scar tissue into bone, or as a reactive process in areas of bone adjacent to some inflammatory focus. Primary and independent ossifying ostitis is observed almost exclusively in syphilis (in late cases of congenital and in the tertiary period of acquired), usually in combination with ossifying periostitis, resulting not only in compaction, but also in thickening of the bone of various shapes and degrees (see Bone). Among bone lesions of a non-inflammatory nature, still often classified in the group of ostitis, ostitis deformans (Paget) and ostitis fibrosa (v. Recklinghausen) (see Ostitis deformans and Ostitis fibrosa) deserve mention. Mother-of-pearl ostitis (bone lesion in mother-of-pearl turners) - see Bone (p. 154). Lit. - see lit. to art. Bone.