Radial tunnel syndrome happens when the radial nerve is squeezed where it passes through a tunnel near the elbow. The nerve roots coming from the spinal cord in the neck join together to form three main nerves that travel down the arm to the hand. One of these nerves is the radial nerve. The radial nerve passes down the back of the upper arm. It then spirals outward and crosses the outside (the lateral part) of the elbow before it winds its way down the forearm and hand.
On the lateral part of the elbow, the radial nerve enters a tunnel formed by muscles and bone. This is called the radial tunnel. Passing through the radial tunnel, the radial nerve runs below the supinator muscle. The supinator muscle lets you turn your hand palm up as if you were holding a bowl of soup.
After the radial nerve passes under the supinator muscle, it branches out and attaches to the muscles on the back of the forearm. The posterior interosseous nerve is a part of the radial nerve in the forearm. After the radial nerve has crossed the supinator muscle, it continues on as the posterior interosseous nerve. If the painful symptoms go away after cutting this
branch the surgeon can safely assume the diagnosis was radial tunnel syndrome.