Wolff's law states what?

• A. Bone remodeling is independent of stress
• B. Bone adapts its strength and density in response to mechanical stresses placed on it
• C. Calcium deposition decreases with weight-bearing
• D. Bone density is fixed after adolescence

Answer: (B)

Wolff's law describes how bone adapts its strength and density in response to mechanical stresses placed on it. When a bone is loaded through weight-bearing activities and muscle pulls, strain is detected by bone cells and triggers remodeling that strengthens areas under the greatest stress. Over time, this leads to thicker bone and trabeculae that align with the lines of force, making the bone better able to handle those stresses. If loading decreases, remodeling shifts toward resorption and bone density can decline, which is why disuse or microgravity environments lead to bone loss. The statement that remodeling happens independently of stress is inconsistent with this idea, and the notions that calcium deposition decreases with weight-bearing or that bone density is fixed after adolescence also misrepresent how bone adapts throughout life.