A determinant of bone architecture. The minimum effective strain.

Minimum effective strain (MES), a hypothesis since 1964, has achieved experimental support. The range is about 0.0008-0.002 unit bone surface strain. Strains below the MES apparently do not evoke adaptive architectural bone modeling, but those above it do. As a key property of living lamellar bone and its intermediary organization, MES offers the potential to predict exactly when and where mechanical loads will cause bone architectural adaptations. MES represents a step toward the goal of constructing a specific, predictive, and quantitative theory of the mechanical determinants of skeletal architecture.