Licence: Public Domain Mark
Credit: Outlines of human pathology / by Herbert Mayo. Source: Wellcome Collection.
Provider: This material has been provided by the Francis A. Countway Library of Medicine, through the Medical Heritage Library. The original may be consulted at the Francis A. Countway Library of Medicine, Harvard Medical School.
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![different appearances found on making sections of inflamed cylindrical bones are the following : — 1. A growth of porous bone superimposed upon the cortex, {d. 20.] 2. Agrowthof compact bone in the same situation. [«?. 21.] 3. An expansion of the cortex through its conversion into porous bone. {d. 24.] 4. An expansion of the cortex, through its apparent sepa- ration into an outer and inner layer, with porous or cancel- lous structure between \d. 25.]; or the expansion consists of an outer part compact, an inner part porous bone. \d. 26.] 5. Expansion of the cortex, with compactness of texture throughout, [d. 23.] 6. The medullary cavity more or less diminished, either by the encroachment of the cortex inwards, or through the solidification of the cancellous structure, [d. 27.] Several of these appearances are often met with together. It is evident what combinations are possible, upon consider- ing how each appearance is produced. The two first have been already accounted for, as consequences of periostitis. The rationale of the production of the four last may be un- derstood by reference to the healthy structure of bone. In the fabric of a healthy cylindrical bone, there seem to be two types of structure: there is, however, in reality but one. The cortical part is not essentially different from the me- dullary. When a dry cylindrical bone has been broken transversely, on examining the surface of fracture with a magnifying glass, the transition from the lightest cancellous structure to the densest part of the cortex is seen to be perfectly gradual; the channels only are narrower, and the partitions stronger, where the grain appears to be closest. In the conversion, therefore, of compact bone into porous bone, all that necessarily takes place is the enlargement of existing cells: in the conversion of porous into compact bone, the partitions only require to be thickened. The va- rieties of enlargement, in the cases 3, 4, and 5, may thus be explained as successive stages of inflammation of the cortex. Simple inflammation of bone is either produced in a single](https://iiif.wellcomecollection.org/image/b21066735_0059.jp2/full/800%2C/0/default.jpg)
