The Science Of Bone — Why Two Thigh Bones Can Date A Lifetime

A brief technical note on why the femur — the thigh bone — is so significant for radiocarbon dating, and why the specific chemical fractions within it require careful separation.

The femur is the longest and largest bone in the human body.

It contains substantial amounts of compact cortical bone — the dense outer layer of bone — and cancellous bone in the interior, surrounding the medullary cavity that produces blood cells.

Cortical bone is the best source of ancient collagen for radiocarbon dating: its dense structure reduces the infiltration of environmental contaminants compared to more porous cancellous bone or to flat bones like the skull.