The femur is the longest bone in the human body. It is also considered the strongest and heaviest bone; this strength is necessary, as the femur carries the weight of the human body when standing or walking.
The femur is the long bone that extends from the pelvis down to the knee cap. It is contained inside the thigh. Human femurs are unusually long and angled in a way that is unique among the apes. These adaptations allow human legs to be very efficient at walking upright. They also provide good mechanical support to the rest of the body when walking or standing. The extreme length of the femur thus makes bipedal posture possible.