Cortical Bone Structure and Mechanical Properties

Cortical bone forms the dense outer shell of long bones and is essential for load bearing, protection of the inner marrow and facilitation of locomotion. Its hierarchical architecture comprises mineralised collagen lamellae organised into osteons, interspersed with Haversian canals and a network of lacunae and canaliculi that govern nutrient transport and cellular activity. Mechanical competence arises from a balance between stiffness, strength and toughness, properties that are finely tuned by variations in porosity, mineral content and collagen orientation. Cortical thickness and porosity evolve with age, disease and mechanical loading, influencing fracture resistance and adaptive remodelling. An improved understanding of these structural and mechanical relationships underpins developments in fracture risk assessment, biomaterial design and orthopaedic implant integration.

Research from Nature Portfolio

Recent studies have employed three-dimensional microcomputed tomography to map cortical porosity and thickness along the superolateral femoral neck in older women. These high-resolution maps reveal subregions where elevated porosity and reduced thickness co-localise, pinpointing potential sites of fracture initiation and challenging reliance on average measures across the entire neck. Complementary work has integrated computed tomography–derived porosity metrics with spherical indentation to predict millimetre-scale elastic modulus and compressive strength of femoral neck cortical samples. By correlating imaging-based porosity with direct mechanical testing, this approach offers a non-destructive pathway to assess bone stiffness, with implications for personalised fracture risk prediction and the optimisation of clinical imaging protocols.

Research from all publishers

Advances in ultrafast ultrasound imaging have been applied to cortical bone assessment using convolutional neural networks coupled with a mutual consensus mechanism. This framework discards noisy measurements and yields enhanced accuracy in predicting cortical thickness (improving from 92% to 95.6%) and porosity classification (from 73.4% to 88.4%) in ex vivo trials, illustrating the potential of rapid, non-ionising diagnostics. In parallel, tensile testing of human femoral diaphyseal cortical bone has demonstrated that tensile yield strain remains remarkably constant (approximately 0.8%) across healthy adults and anatomical quadrants, independent of elastic modulus or yield stress variations. This invariance simplifies the definition of failure thresholds in biomechanical modelling and supports the development of generalised criteria for bone strength prediction in finite element simulations.

Cortical Bone Structure and Mechanical Properties publication trend

The graph below shows the total number of articles in cortical bone structure and mechanical properties across all publications each year (not limited to Nature Index journals).

Technical terms

Cortical porosity: The volume fraction of microscopic void spaces within the cortical matrix affecting mechanical strength.

Cortical thickness: The perpendicular distance between periosteal and endosteal surfaces, reflecting structural robustness.

Elastic modulus: A measure of stiffness expressing the ratio of stress to elastic strain under load.

Yield strain: The deformation threshold beyond which permanent damage and plasticity occur.

Osteon: The fundamental cylindrical unit of cortical bone, comprising concentric lamellae around a central canal.

Ultrafast ultrasound: A high-speed acoustic imaging technique capturing rapid radiofrequency data for microstructural assessment.

Spherical indentation: A mechanical test using a spherical probe to determine local bone stiffness at millimetre scales.

References

1. A Consensus Mechanism to Improve Prediction of Cortical Bone Properties Using Ultrafast Ultrasound Acquisition. IEEE Access (2024).
2. Tensile Yield Strain of Human Cortical Bone from the Femoral Diaphysis Is Constant among Healthy Adults and across the Anatomical Quadrants. Bioengineering (2024).
3. Computed tomography porosity and spherical indentation for determining cortical bone millimetre-scale mechanical properties. Scientific Reports (2019).
4. Three-dimensional mapping of cortical porosity and thickness along the superolateral femoral neck in older women. Scientific Reports (2022).