Which test is commonly used to evaluate nerve function with TOS and is part of diagnostic workup?

• A. MRI
• B. EMG/NCV testing
• C. Doppler
• D. Venography

Answer: (B)

Emg/NCV testing directly measures how well the nerves and muscles are functioning, which is essential when suspected thoracic outlet syndrome involves nerve compression. By evaluating nerve conduction and looking for signs of denervation or chronic reinnervation in muscles supplied by the lower brachial plexus (often C8–T1), this test provides objective evidence of nerve involvement and helps localize the affected nerve pathways. It also helps distinguish neurogenic TOS from vascular causes, which imaging alone might not clarify. Imaging like MRI can show anatomical crowding, and Doppler or venography assess blood flow, but they don’t quantify nerve function. That direct assessment of nerve activity is what makes EMG/NCV a key part of the diagnostic workup.