The tensile fracture stress (σfr) of longitudinal bovine tibia compact bone specimens was measured as a function of the length (c) and radius of curvature (r) of machined edge cracks. It was established that, for a given value of r, then
σfr = Ae10.5 - B
where A and B are constants. A fracture mechanics method was utilised to derive values of the fracture toughness (as defined by the critical stress intensity factor, KIC), the specific surface energy (7) and the “intrinsic” flaw size (c0). The advantages and limitations of this approach are discussed.