What structural organization characterizes mature bone histology?

• A. Compact bone with osteons and cancellous bone
• B. Lamellar bone with osteons but no trabeculae
• C. Cancellous bone only
• D. Dense irregular bone matrix

Answer: (A)

Mature bone histology is organized into two interconnected forms: dense outer compact bone and inner cancellous (spongy) bone. The compact bone is built from osteons (Haversian systems), with concentric lamellae arranged around a central blood vessel-containing canal. This gives a very orderly, layered structure. Inside the bone, cancellous bone forms a lattice of trabeculae that are also made of lamellae and house osteocytes in lacunae, with marrow spaces between them. This combination—compact bone with its osteons plus cancellous bone with trabeculae—characterizes mature bone. The other descriptions either omit the presence of trabeculae or misstate the organized lamellar arrangement.