Where is the radius located in reference to the ulna?

The ulna and radius are the two bones of the forearm. The radius bone is shorter than the ulna and is prism-shaped long bone. The radius is a more lateral and slightly shorter of the two forearm bones. It is found on the thumb side of the forearm and rotates to allow the hand to pivot at the wrist. It pivots around the ulna to produce movement at the proximal and distal radio-ulnar.

The anatomical position is defined to be the body standing upright with face and torso and feet directed forward and arms around 45 degrees away from the torso with palms facing forward. This is a standard reference in human anatomy, especially in describing body part relations (i. e. the 5th digit of the hand is medial to the umbilicus, etc.). The radius, in anatomical position is lateral to the ulna as ulna is closer to the midline.