A patient with thoracic outlet syndrome shows pain, tingling, and a diminished radial pulse when the arm is extended and externally rotated. Which test would confirm thoracic outlet syndrome?

• A. Roos
• B. Clunk
• C. Speed
• D. O'Brien

Answer: (A)

The test that best confirms thoracic outlet syndrome is a provocative maneuver that reproduces the compression of the neurovascular structures when the arms are in a position that narrows the thoracic outlet. In this scenario, the described symptoms—pain, tingling, and a diminished radial pulse when the arm is extended and externally rotated—fit the pattern seen with thoracic outlet compression. The Roos test specifically places the arms in about 90 degrees of abduction with external rotation and elbow extension, then the patient opens and closes the hands for several minutes. If neurovascular symptoms appear or the pulse diminishes during this position, it strongly supports thoracic outlet syndrome.

The other tests target different shoulder structures. The clunk test assesses shoulder instability or labral pathology, not thoracic outlet compression. The Speed test checks for bicipital tendinopathy. The O’Brien test screens for labral (superior) pathology around the shoulder joint. They don’t provoke the neurovascular compression seen in thoracic outlet syndrome like Roos does.