Fig. (1) Photomicrograph of a synchondrosis in neonatal mice showing different zones across one side of the synchondrosis. (A) Zone of vascular erosion and invasion. (B) Zone of chondrolacunar hypertrophy and matrix calcification. (C) Zone of matrix production or matrixogenic zone. (D) Zone of cellular proliferation. (E) Central zone or resting zone.