Ulna
The ulna was a bone in the Human skeletal system. Together with the , it formed the bone structure of the forearm. 

When solanogen-based lifeforms conducted experiments on Commander William T. Riker, they severed his forearm. When reattaching the arm, they created an offset of 0.2 microns, visible in a scan of the bone structure of his ulna and radius. ()

In 2371, Walter Baxter suffered localized tenderness to his ulnar bone while working out in the gymnasium aboard the . ()

External link 
 

Bones