. The elements of pathological histology with special reference to practical methods . rect transformation, on the one hand the cartilage-cells at oticebecome bone-cells by acquiring processes while their cavities assumeserrated forms; and on the other, lime is deposited in the interstitialsubstance (Fig. 180, b). In the indirect transformation, however,the cartilage dissolves, whilst its cells first become marrow-cells, 360 THE OSSEOUS SYSTEM and only subsequently bone-corpuscles. Besides this, a portion ofthe newly-formed tissue may also change first into fibrillated con-nective tissue, this
. The elements of pathological histology with special reference to practical methods . rect transformation, on the one hand the cartilage-cells at oticebecome bone-cells by acquiring processes while their cavities assumeserrated forms; and on the other, lime is deposited in the interstitialsubstance (Fig. 180, b). In the indirect transformation, however,the cartilage dissolves, whilst its cells first become marrow-cells, 360 THE OSSEOUS SYSTEM and only subsequently bone-corpuscles. Besides this, a portion ofthe newly-formed tissue may also change first into fibrillated con-nective tissue, this subsequently becoming bone. In the manner just described new bone {external and internalcallus) is formed not only on the surface of the broken ends, butbetween them [definitive callus], being most strongly developed inthe immediate neighbourhood of the seat of fracture, and graduallydecreasing in bulk as it recedes from the latter. This bone is atfirst very spongy, , it still contains numerous and relativelylarge cancellous spaces, filled with a medullary tissue rich in cells. Fio. 181.—External Callus of a Four-Weeks-Old Fracture of the Coronoid ProcessOF the Ulna, x 70. (Haematoxylin and eosin.) a, Narrow trabeculse of bone, with uunierousbone-corpuscles,Imore or less densely packed ; h, Large cancellous spaces, containing tissue richin cells and vessels. and blood-vessels (Fig. 181, b); but later it becomes more and morecompact owing to the continual deposition from both periosteumand medullary spaces of new bony trabeculse upon the old. Aftera still longer time (in the course of years) a partial reabsorptionof the callus takes place, all parts not required for the function ofthe bone being in this way removed. If the broken ends are widely separated, or are continually shiftingone on the other, or are insufficiently nourished, the bone eitherremains altogether ununited, or there ensues a mere union by fibrousmasses (pseudarthrosis). In the former case a kind of join
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectpatholo, bookyear1895
