Lamellae are the concentric rings of bone matrix within an osteon. Which option best describes them?

• A. Central canals
• B. Lacunae
• C. Lamellae
• D. Osteons

Answer: (C)

Lamellae form the concentric rings of bone matrix that surround the central canal in each osteon. This layered arrangement gives compact bone its strength, with collagen fibers in each lamella aligned in a specific direction and alternating between layers to resist twisting. The spaces between these rings are lacunae, which house osteocytes, and tiny canaliculi connect those lacunae to each other and to the central canal so nutrients and waste can travel. The central canal itself is the hollow channel containing blood vessels and nerves. An osteon is the entire unit comprising the central canal plus its surrounding lamellae; central canals are the channels, lacunae are the cell spaces, and osteons are the whole structural units. Describing them as concentric rings best identifies lamellae.