Which zone in the growth plate is most associated with the onset of ossification?

Which zone in the growth plate is most associated with the onset of ossification?

• A. Ossification Zone
• B. Zone of Proliferation
• C. Zone of Resting
• D. Zone of Calcification

Answer: (A)

Endochondral ossification begins where bone-forming cells invade and replace the cartilage with bone. That invasion and replacement happen in the zone of ossification, so this is the region where ossification starts. The zone of calcification is just before that step—cartilage matrix calcifies and chondrocytes die, providing a scaffold but not yet bone. The zone of proliferation contributes to growth in length, while the zone of resting is relatively quiescent. So, the onset of ossification is best associated with the zone of ossification.

Endochondral ossification begins where bone-forming cells invade and replace the cartilage with bone. That invasion and replacement happen in the zone of ossification, so this is the region where ossification starts. The zone of calcification is just before that step—cartilage matrix calcifies and chondrocytes die, providing a scaffold but not yet bone. The zone of proliferation contributes to growth in length, while the zone of resting is relatively quiescent. So, the onset of ossification is best associated with the zone of ossification.