What fraction of bone is made up of inorganic salts?

Bone is primarily composed of both organic and inorganic components. The inorganic part of bone primarily consists of mineral salts, predominantly hydroxyapatite, which is made of calcium phosphate. These minerals provide bone with its hardness and strength.

In adults, approximately two-thirds (or 66%) of bone mass consists of these inorganic salts, making the fraction 2/3. This significant proportion is crucial for the mechanical properties of bone, allowing it to withstand compressive forces.

The organic components, which mainly include collagen fibers and various proteins, account for about one-third of bone mass. This collagen is vital for providing flexibility and tensile strength to the bones, balancing the rigidity afforded by the inorganic components.

Understanding the composition of bone is important, particularly concerning how it responds to various physiological and pathological conditions. The majority of bone's weight and structural integrity stem from the inorganic salts, highlighting their critical role in overall bone health and function.