On articular cartilage / by Alex. Ogston.

  • Alexander Ogston
Date:
[1875]
Catalogue details

Licence: Public Domain Mark

Credit: On articular cartilage / by Alex. Ogston. Source: Wellcome Collection.

    6/42 (page 54)
    reaching the margin of the bone, a most active proliferation and subdivision of its component cells commences at the end next the bone and quickly invades the rest of the group, which thus becomes converted into one of the prominences. In this proli¬ feration the cells lose their capsule, and, ceasing to be recog¬ nisable as cartilage-cells, form by the process of multiplication a large mass of granulation tissue composed of small rounded cells, each about -^soq an in°b in diameter, with granular protoplasm and large central nucleus whose diameter is about one half of that of the cell. It occasionally happens that one end of the cartilage-group still possesses its characteristic cells, while the other end is changed into granulation tissue (Fig. 2, c, c), but commonly the process once commenced is very rapid in involving the whole group. From this it is clear that the prominences are really groups of cartilage-cells which have un¬ dergone alteration. The alteration consists in a transmutation into a tissue not to be distinguished from medullary tissue such as occupies the cancelli of the spongy bones, in fact iden¬ tical with it, and not unfrequently developing, like it, fat cells at various points. It is not easy to see this process distinctly taking place. Out of a large number of sections there may be only one or two which exhibit it so clearly as in Fig. 2 of the accompanying plate, but once it has been observed in its entirety it is easy to recognize it in almost every section, and it seems to be a uni¬ versal feature in the passage of the one structure into the other. The masses of granulation tissue thus formed are next transformed into true bony tissue, but the transformation shows appearances which vary a good deal according to the activity of growth. Sometimes the masses coalesce and form a layer (Fig. 2, e) between the cartilage and the bone, and on the sur¬ face of the layer next the bone the cells become transformed into bone-corpuscles (Fig. 2,/). This is attended by a con¬ siderable increase of their intercellular substance, so that each cell separates to a little distance from its fellows, the inter¬ cellular substance becoming hard by the deposition in it of calcareous salts, and the cells taking on the outlines of bone- corpuscles with imperfectly formed and not very numerous