The Femur

bones · human body · super strong

The strongest bone. Your femur is incredibly tough, made to support your entire body weight when you walk, run, and jump. It's much thicker and denser than other bones.

One bone per thigh. Unlike your arm, which has two bones (radius and ulna), your thigh has just one main bone: the femur. This single powerful bone does all the heavy lifting.

Longer than you'd guess. The femur is the longest bone in your body, stretching from your hip to your knee. In adults, it can be about 19 inches long.

Built for movement. The femur connects your hip to your knee, creating the pivot point that lets you walk, kick, and run. Powerful muscles wrap around it to make movement possible.

Four-legged animals too. Every mammal from dogs to dinosaurs to whales has femurs in their back legs. It's one of the most important bones across the entire animal kingdom.