What makes the bones strong yet light?

Bones are composed of a matrix of proteins, primarily collagen, reinforced with calcium phosphate (in the form of hydroxyapatite). This combination of materials makes bones strong and stiff to withstand mechanical forces, yet also light enough for the body to carry.

Collagen, a fibrous protein, provides the flexibility and tensile strength of bones. It acts like a scaffold that gives the bones their shape and resilience. Calcium phosphate is a mineral that forms crystals that grow within the collagen matrix. These crystals add rigidity and hardness to bones, making them resistant to compression.

The combination of the organic (collagen) and inorganic (calcium phosphate) components of bones results in a unique material known as osseous tissue, which is lightweight yet highly durable. The density and arrangement of the collagen and calcium phosphate give bones their characteristic strength and flexibility, enabling them to withstand significant loads without breaking or deforming.