Leonardo Da Vinci , among his many talents also contributed to the study of the skeleton, albeit unpublished in his time. Osseous tissue slowly replaces the cartilage and fibrous tissue in a process called calcification. Preview watermarked images inside your designs to make sure they look just right. If not, then the following diagram will prove to be very useful. These tissues act as a soft, growing framework and placeholder for the bony skeleton that will replace them.