In appositional growth, the primary change in bone dimensions is an increase in what?

• A. Increase in width
• B. Increase in length
• C. Formation of medullary cavity
• D. Cartilage deposition

Answer: (A)

Appositional growth widens a bone’s diameter. Osteoblasts in the periosteum add new bone to the outer surface, increasing thickness and overall width. While the inner surface can be resorbed to keep the marrow cavity proportionate, the key dimensional change during this process is an increase in width. Lengthening, by contrast, occurs at the growth plates through endochondral ossification, not through appositional widening. Cartilage deposition is involved in initial bone formation but not the widening that characterizes appositional growth.