In endochondral ossification, the zone of the epiphyseal plate where chondrocytes die and their lacunae become calcified to serve as scaffolding for bone deposition is called:
- A Zone of calcification (zone of provisional calcification) ✓
- B Zone of proliferation
- C Zone of hypertrophy
- D Zone of reserve (resting zone)
Explanation
The epiphyseal growth plate has five zones (from epiphysis to metaphysis): (1) Reserve/resting zone — stem chondrocytes; (2) Proliferative zone — rapidly dividing chondrocytes in columns; (3) Hypertrophic zone — enlarged chondrocytes producing type X collagen; (4) Zone of provisional calcification — chondrocytes die, their matrix becomes calcified, providing a scaffold for osteoblasts; (5) Zone of ossification — osteoblasts deposit bone on the calcified cartilage matrix, forming primary spongiosa. Rickets/osteomalacia disrupts the zone of calcification due to inadequate mineralization. Achondroplasia disrupts the proliferative zone (FGFR3 inhibits chondrocyte proliferation).
Reference: BD Chaurasia's Human Anatomy, 8th ed.
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Written and medically reviewed by the StethoPrep medical team.