The histological difference between compact (cortical) and cancellous (trabecular) bone is best described by which feature?
- A Compact bone contains osteons (Haversian systems); cancellous bone has trabeculae with marrow spaces between them and no Haversian systems ✓
- B Compact bone is unmineralised osteoid; cancellous bone is fully mineralised
- C Compact bone is made of woven bone; cancellous bone is lamellar bone
- D Compact bone lacks canaliculi; cancellous bone has an extensive canalicular network
Correct answer: A. Compact bone contains osteons (Haversian systems); cancellous bone has trabeculae with marrow spaces between them and no Haversian systems
Explanation
Compact bone is organised into cylindrical Haversian systems (osteons) — concentric lamellae surrounding a central Haversian canal containing blood vessels, with Volkmann's canals connecting them transversely. Lacunae containing osteocytes are connected by canaliculi. Cancellous (spongy/trabecular) bone consists of a lattice of bony trabeculae with marrow-filled spaces between; it lacks well-developed Haversian systems but still contains lamellae and canaliculi within trabeculae. Both types contain mineralised lamellar bone; woven bone is an immature/pathological form.
Reference: BD Chaurasia's Human Anatomy, 8th ed.
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