EPIPHYSEAL DISC – 5
Five Regions or Zones may be observed in an epiphyseal disc. They show a sequence of transformations of cartilage cells that at the end of the disk are replaced by bone cells and bone tissue.
Observing the disc from the epiphysis toward the diaphysis each Region or Zone is seen to undergo a (subtle) transition to the next and for this reason the boundaries between the zones are precise.
Observing the disc from the epiphysis toward the diaphysis each Region or Zone is seen to undergo a (subtle) transition to the next and for this reason the boundaries between the zones are precise.
From the epiphysis toward the diaphysis the following Zones form the epiphyseal disk:
1 – Zone of resting cartilage
2 – Zone of proliferation
3 – Zone of hypertrophic cartilage
4 – Zone of calcification
5 – Zone of ossification
The first four zones are made of cartilaginous tissue and the last zone of newly produced bone tissue.
The zones will be described in detail on the next pages.
Zones of the Epiphyseal disc seen in a longitudinal section of the bone. Staining: HE. Magnification: small.
