| Abstract: | The smoothness characteristic of synovial joint surfaces of bare bones is shown to be an illusion; low‐power microscopy of young adult human bones from interments revealed, on the surfaces of a variety of synovial joints, a system of basically hemispherical elevations, often united as short chains or groups. This system was also found on joints of a variety of species of six mammalian orders. Under the higher magnification of scanning electron microscopy (SEM), many elevations had a pit at their summits. The bare‐bone surfaces of synovial joints have a thin covering of mineralized cartilage, including its mineralizing‐front, which survives taphonomic processes, as well as the preparative procedures used in the study of articular surfaces. In its formative phase, the front has the chondrocyte–columnar structure of cartilage. It is postulated here that the newly‐discovered elevations arise when cartilage formation is ceasing, or becoming dormant, and that each column‐unit produces a globular mineralized mass, often with a pit which had accommodated a chondrocyte. These masses may incorporate the fibre systems of the unmineralized cartilage and aid in its attachment to the bony surface. Copyright © 2001 John Wiley & Sons, Ltd. |
