Question

On application of tensile forces, cancellous bone exhibits a brittle behavior but yielding occurs under:

• A. Longitudinal bending
• B. Transverse bending
• C. Compressive loading
• D. Torsion

Hint:

Think of spongy cancellous bone like an industrial metal or polymer foam: - Pull it in tension, and the thin individual segments snap abruptly with brittle characteristics. - Crush it in compression, and the cells progressively buckle and collapse inward. This structural collapse creates a long, energy-absorbing yielding plateau before the material fully solidifies.

Answer 1

The Correct Option is C

Concept: Cancellous bone (also known as trabecular or spongy bone) is the highly porous, honeycombed interior bone tissue found at the ends of long bones and inside vertebrae. Unlike dense cortical bone, cancellous bone consists of a lattice of thin branching ribs and plates called trabeculae. This open cellular structure gives cancellous bone unique mechanical properties that resemble porous engineering foams.

Step 1: Examining tensile behavior.
When a tensile (pulling) force is applied to cancellous bone, the thin trabecular cross-bridges are pulled apart directly. Because these mineralized structures are inherently rigid and lack ductile reinforcing mechanisms when under tension, the trabeculae snap abruptly. This causes the structure to snap rapidly without significant plastic deformation, which describes classic brittle failure behavior.

Step 2: Examining behavior under compressive loading.
When cancellous bone is subjected to compressive loading, its open porous network changes its deformation mechanism entirely:
• Initial loading causes elastic bending of the individual trabecular rods.
• Once the stress reaches the yield point, the weak micro-walls experience progressive, controlled buckling, micro-fracturing, and crushing into the open pore spaces.
• This continuous, sequential collapse allows the bone tissue to undergo significant post-yield deformation at a relatively constant stress level. This prolonged mechanical collapse mimics a classic plastic yielding region seen in cellular foams, preventing catastrophic snap failures. Therefore, structural yielding in trabecular bone is uniquely prominent under compressive loading, matching Option (C).