Zone of erosion or retrogression.. The death and decomposition of cartilage cells and the containment of cavities on the primary pure. The calcareous thrombocytopenia is darker

Zone of erosion or retrogression:
The cartilage cells in this region are dead and decomposed. The interstitial material that separates the cells of one row is broken, so the gaps are open to each other. The cavities contain primary marrow, and the calcareous thorns separating the columns from each other still remain dark.