Which statement best describes a positive finding on provocative TOS testing?

• A. Increased radial pulse with arm movement
• B. No change in pulse with provocative maneuver
• C. Pulses are palpable with arm elevated
• D. Decreased or absent radial pulse during provocative maneuvers

Answer: (D)

Provocative testing for thoracic outlet syndrome looks for compression of the vessels or nerves when the arm is placed in positions that narrow the outlet. A positive finding for the vascular component is a decreased or absent radial pulse during the provocative maneuver, indicating arterial compression of the subclavian artery as the limb is stressed. The pulse should recover once the arm returns to a neutral position, which helps confirm the effect is positional. If the pulse remains unchanged, or actually increases, that suggests no vascular compromise, and a positive result would not be observed.