How do the metaphyseal of a bone determine the age of a skeleton?

Long bones are composed of a diaphysis (shaft) and
epiphysis (rounded ends).  At the bottom of the epiphysis you find the metaphysis, which
contains the epiphyseal "growth" plates which are responsible for growth in the length
of the bone.  Throughout childhood and into adolescence, this area contains cartilage
that allows such growth to occur.  Over time, ossification turns the cartilage into
bone.  In early adulthood the cartilage stops growing and the epiphyseal plate
completely ossifies so the bone can no longer grow in
length.

By looking at the amount of cartilage relative to
bone in the metaphyseal area, one might determine whether the skeleton was that of a
child, adolescent, or adult.