What is the femur?

The femur is the main bone of the upper leg and connects the hip joint to the knee joint. It is the body’s longest and strongest bone, built to support weight, enable walking, running, and jumping, and withstand major forces. The top of the femur fits into the pelvis at the hip, while the lower end helps form the knee joint. Because it is so strong, the femur is harder to break than many other bones, though femur fractures usually require significant trauma. Its structure is crucial for human locomotion and balance.