When you're born, you have 270 bones. But an adult has only 206 bones. What happens? Many bones, such as those that make up the skull and spine, fuse together as you grow.

Most people have 12 pairs of ribs, but about 5 percent of the population has an extra pair.

The tiniest bone in the body is the stirrup bone in the ear, which is less than an inch long. The longest bone is the femur, which varies in length from person to person but is about one-fourth of a person's overall height.

Hand over foot: There are 54 bones in all in your wrists, hands and fingers but only 52 in both feet, ankles and toes.