What percentage of bone consists of inorganic substances?

• A. 50%
• B. 75%
• C. 80%
• D. 90%

Answer: (B)

Bone is a composite material primarily composed of both organic and inorganic components, which work together to provide structural integrity and function. The inorganic portion of bone is mostly made up of hydroxyapatite, a mineral form of calcium phosphate, which contributes significantly to the bone's stiffness and ability to bear weight.

The correct percentage of bone that consists of inorganic substances is approximately 70-80%. This indicates that option B, stating 75%, is a reasonable approximation of the inorganic content in bone. The inorganic material is essential for maintaining the strength of the skeletal system, while the organic part, which includes collagen and other proteins, contributes to the flexibility and resilience of bone.

Understanding the composition of bone is crucial in fields such as bone densitometry, as it influences bone health assessments, fracture risk evaluations, and the effects of various diseases such as osteoporosis.