Investigating the structural optimisation of bone through computational biomechanical modelling

Bones are structurally organised to be lightweight (to minimise energy expenditure during movement), but also have sufficient strength to withstand musculoskeletal and other environmental forces. This is often achieved through utilising a “sandwich” structure whereby a dense thin layer (cortical bone) creates a shell that is supported internally by a network of porous (trabecular) bone. The structure of cortical and trabecular bone is known to adapt to mechanical force, but how it adapts may vary with anatomical location and bone type. 

The structural adaptation of bone in relation to mechanical force is often investigated through finite element analysis; a computational technique that can determine the stresses and strains in bones, and can also be used in conjunction with adaptive remodelling algorithms to predict an optimal structural arrangement for a given mechanical load. This project will investigate the structural adaptation of cortical and trabecular bone by using birds as a case study. Some bird bones are known to possess a heterogeneous cortical shell and a complex arrangement of internal trabecular bone. However, whether this structural arrangement is adapted to: 1) resist musculoskeletal forces; 2) make the bone lightweight for the purpose of flight; or 3) a combination of both, remains unknown. This project will initially characterise the structure of either skull, foot, and wing bones in birds through a histomorphometric analysis, and then create micro-finite element models to: 1) analyse the strains within the bone in relation to musculoskeletal forces; 2) use adaptive remodelling algorithms to predict the optimal bone (external and internal) structure to resist this loading. The predicted optimal bone structure will then be compared to the actual bone structure in flying and flightless birds to assess the extent to which the bone is adapted to the musculoskeletal forces vs weight reduction.