Intersection Syndrome describes a condition in which the radial-side wrist extensor tendons that cross under the wrist retinaculum —the fibrous band of fascia that covers the carpus—and serve to extend the wrist become irritated from overuse. The long thumb extensor is sometimes involved too.
Activities that entail repeatedly moving the wrist up and down—such as tennis, rowing, kayaking or skiing—can lead to Intersection Syndrome, which is indicated by pain on the back of the forearm a few inches below the wrist as well as a creaking sound/sensation as the tendons rub against the extensor retinaculum.
The condition is normally treated by rest, splinting, anti-inflammatory medications and cortisone injection, followed by physical therapy. Surgery is only occasionally implicated.