Intermittent compression of the brachial plexus causing arm/hand pain, weakness, and paresthesia describes which syndrome?

• A. Carpal tunnel syndrome
• B. Bicipital tendinopathy
• C. Thoracic outlet syndrome
• D. Ulnar nerve entrapment

Answer: (C)

Compression of the brachial plexus as it passes through the thoracic outlet causes neurogenic symptoms in the shoulder and upper limb, including arm and hand pain, weakness, and paresthesias. When the outlet space is narrowed by structures like the scalene muscles, the first rib, or the clavicle, or by tension from the chest wall (such as with certain arm positions), the nerves are intermittently irritated or compressed. This pattern fits thoracic outlet syndrome, where symptoms reflect brachial plexus involvement rather than a lesion at the wrist or elbow.

Carpal tunnel syndrome affects the median nerve at the wrist and typically produces numbness or tingling in the thumb, index, middle, and half of the ring finger, often at night, without primary arm weakness. Bicipital tendinopathy is a shoulder tendon problem causing anterior shoulder pain, not brachial plexus–level symptoms. Ulnar nerve entrapment produces numbness and weakness in the ulnar distribution (pinky and half of the ring finger) and intrinsic hand muscles, not brachial plexus–driven arm/hand pain with intermittent neurogenic symptoms.