The radius is one of the two bone

Bone

Bones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...

s in the forearm

Forearm

-See also:*Forearm flexors*Forearm muscles...

.

The radius

Radius (bone)

The radius is one of the two large bones of the forearm, the other being the ulna. It extends from the lateral side of the elbow to the thumb side of the wrist and runs parallel to the ulna, which exceeds it in length and size. It is a long bone, prism-shaped and slightly curved longitudinally...

 is ossified from three centers: one for the body, and one for either extremity. That for the body makes its appearance near the center of the bone, during the eighth week of fetal life.

About the end of year, ossification commences in the lower end; and at the fifth year, in the upper end.

The upper epiphysis

Epiphysis

The epiphysis is the rounded end of a long bone, at its joint with adjacent bone. Between the epiphysis and diaphysis lies the metaphysis, including the epiphyseal plate...

fuses with the body at the age of seventeen or eighteen years, the lower about the age of twenty.

An additional center sometimes found in the radial tuberosity, appears about the fourteenth or fifteenth year.