The lack of motion stimulates osteogenesis.

• A. The lack of motion stimulates osteogenesis
• B. Motion stimulates osteogenesis
• C. No effect
• D. Osteogenesis occurs with thermal necrosis

Answer: (A)

The main idea is that bone formation is driven by mechanical loading. When bone experiences strain from weight-bearing or movement, osteocytes sense that mechanical signal and trigger pathways (such as Wnt signaling and IGF-1 effects) that stimulate osteoblasts to form new bone. This process is known as mechanotransduction, and it underlies Wolff’s law: bone adapts its mass and structure in response to the forces it experiences.

Because of this, motion and loading promote osteogenesis, while a lack of motion (disuse) reduces the stimulus for bone formation and shifts the balance toward bone resorption. In practical terms, keeping joints and bones subjected to appropriate mechanical load helps maintain or increase bone density, whereas immobilization or inactivity leads to bone loss.