There are 206 bones in the skeletal system of an adult, compared to about 270 bones in an infant or newborn baby.

This is because some smaller bones fuse together during development as the baby grows.  These smaller bones include the vertebral column and the sacrum.

In particular, the sacrum or the group of bones at the base of the spine, consists of five bones that are separated at birth, but fuse together into a solid structure years later.

Most bones are in the hands, feet and face.  The human hand has 27 bones, while the foot has 26 and the face has 14.