What determines the bending strength of compact bone?

The bending strength of a wide variety of bony types is shown to be nearly linearly proportional to Young's modulus of elasticity/100. A somewhat clos er and more satisfactory fit is obtained if account is taken of the variati on of yield strain with Young's modulus. This finding strongly suggests tha t bending strength is determined by the yield strain. The yield stress in t ension, which might be expected to predict the bending strength, underestim ates the true bending strength by approximately 40%, This may be explained by two phenomena. (1) The post-yield deformation of the bone material allow s a greater bending moment to be exerted after the yield point has been rea ched, thereby increasing the strength as calculated from beam formulae. (2) Loading in bending results in a much smaller proportion of the volume of t he specimens being raised to high stresses than is the case in tension, and this reduces the likelihood of a weak part of the specimen being loaded to failure.