Where is a long bone strongest?

Where is a long bone strongest?

• A. At the center of the diaphysis
• B. At the epiphysis
• C. At the metaphysis
• D. Near the growth plate

Answer: (A)

A long bone is strongest in the center of the shaft, the diaphysis. This region has a thick, dense cortical bone shell, which gives the greatest cross-sectional moment of inertia. In bending and axial loading, strength increases with how far bone material can be distributed from the neutral axis, so the midshaft’s sturdy cortex provides the most resistance to fracture. The ends (epiphyses) contain more cancellous bone and articular cartilage, which are geared toward joint surfaces and energy absorption rather than maximal bending strength. The metaphysis near the growth plate is a transitional zone with less dense bone, making it comparatively weaker in bending. That combination makes the center of the diaphysis the strongest part.

A long bone is strongest in the center of the shaft, the diaphysis. This region has a thick, dense cortical bone shell, which gives the greatest cross-sectional moment of inertia. In bending and axial loading, strength increases with how far bone material can be distributed from the neutral axis, so the midshaft’s sturdy cortex provides the most resistance to fracture. The ends (epiphyses) contain more cancellous bone and articular cartilage, which are geared toward joint surfaces and energy absorption rather than maximal bending strength. The metaphysis near the growth plate is a transitional zone with less dense bone, making it comparatively weaker in bending. That combination makes the center of the diaphysis the strongest part.