Which description correctly distinguishes cortical (compact) bone from trabecular (spongy) bone?

• A. Cortical bone consists mainly of collagen with little mineral, is spongy in appearance under low magnification and more susceptible to early bone loss compared to trabecular bone which is a compact shell surrounding marrow cavities.
• B. Cortical bone and trabecular bone are identical in composition and function; the terms are used interchangeably in physiology texts, with no difference in susceptibility to bone loss in adults.
• C. Cortical bone forms the dense outer shell with microscopic pores and high mineral content; trabecular bone is the inner lattice-like structure with larger spaces and greater surface area relative to volume.
• D. Cortical bone is the porous inner scaffold that contains marrow and is more metabolically active than the dense outer layer; trabecular bone is the continuous dense outer cortex that slowly remodels over decades.

Answer: (C)