In thoracic outlet syndrome the brachial plexus, the subclavian artery or the subclavian vein is squeezed in the space between the collarbone, first rib and scalene muscles. The neurogenic form is by far the most common, while the venous and arterial forms are rarer but can cause clots.
Key symptoms
- Pain in the neck, shoulder and arm, worse with overhead activity
- Numbness and tingling, often in the ring and little fingers
- Arm fatigue and weak grip
- Arm swelling and bluish color (venous form)
- Cold, pale hand or finger pain (arterial form)
What you find on exam
- Tenderness over the scalene muscles that reproduces symptoms
- Elevated arm stress test: hands up, open and close for 3 minutes
- Pulses and blood pressure in both arms with arm positions
- Hand muscle wasting and sensory loss on the inner hand and forearm
- Arm swelling, dilated chest wall veins or cool, pale fingers
Tests
- Chest and neck X-ray: cervical rib or abnormal first rib
- Nerve conduction studies and electromyography to rule out other nerve problems
- Duplex ultrasound of the arm vessels with positional maneuvers
- CT or MR angiography or venography if a vascular form is suspected
Treatment basics
- Physical therapy for most neurogenic cases: posture, scalene stretching and strengthening
- Activity changes and NSAIDs such as ibuprofen for pain
- Venous clot: anticoagulation, often with catheter-directed thrombolysis
- Surgical decompression (first rib resection, scalenectomy) if therapy fails or for vascular forms
Red flags
- Sudden painful swelling of the whole arm (subclavian vein thrombosis)
- Cold, pale, pulseless hand or finger ulcers
- Progressive hand weakness and muscle wasting
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Sources: NCCPA PANCE Content Blueprint; NBOME COMLEX-USA clinical presentations; AAMC Core Entrustable Professional Activities (Core EPAs). Written by Making Synapses. Making Synapses is not affiliated with these organizations.