When you rotate your arm, which bone is actually rotating (turn your palm from facing down to facing up)?
The radius, the forearm bone that aligns with the thumb, rotates over the ulna. If you place one hand on this bone when you rotate the other arm you will be able to feel this movement. You will not feel movement of the ulna when the arm is rotated.
Asked by Eugene Fenster · Last updated 6 months ago · 15.6K views