Theory 43/Geometry & Scale/Bone mechanics
Bone Strength Is Geometry
The claim
Bone strength is set by cross-sectional geometry rather than by mass, so two bones of equal mass can differ several-fold in bending strength.
01Mechanism
Bending resistance depends on the second moment of area, which rises with the cube of the radius while mass rises with the square.
02Prediction
Strength should track the section modulus, not mass.
03Refutation
Strength tracking mass would remove the geometry.