How are the trabeculae oriented in cancellous bone under load?

How are the trabeculae oriented in cancellous bone under load?

• A. Parallel to lines of stress with the vertical and horizontal components
• B. Perpendicular to the lines of stress
• C. Random orientation
• D. Parallel to growth lines

Answer: (A)

Bone adapts its internal scaffold to the directions of mechanical load, aligning trabeculae along lines of principal stress. This remodeling along the resultant stress vector—which has both vertical (axial) and horizontal (bending) components—optimizes strength where it’s needed and minimizes material use. In cancellous bone, this means trabeculae grow parallel to the direction that most effectively resists the combined forces, enhancing stiffness in the loading direction. Perpendicular, random, or growth-line–based orientations don’t provide the same efficient resistance to the actual loading pattern, so they’re not favored by the remodeling process.

Bone adapts its internal scaffold to the directions of mechanical load, aligning trabeculae along lines of principal stress. This remodeling along the resultant stress vector—which has both vertical (axial) and horizontal (bending) components—optimizes strength where it’s needed and minimizes material use. In cancellous bone, this means trabeculae grow parallel to the direction that most effectively resists the combined forces, enhancing stiffness in the loading direction. Perpendicular, random, or growth-line–based orientations don’t provide the same efficient resistance to the actual loading pattern, so they’re not favored by the remodeling process.