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Thoracic outlet syndrome

Thoracic outlet syndrome is compression of the brachial plexus, the subclavian vein or the subclavian artery in the passage between the first rib, the scalene muscles and the clavicle; the neurogenic form is the great majority and is first treated with physiotherapy, the venous form presents as effort thrombosis (Paget–Schroetter) and is treated with thrombolysis and first rib resection, and the arterial form — rare and dangerous — presents with emboli to the hand and requires surgery.

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Why it matters in the exam

The exam mainly tests recognising the type from the clinical picture. The neurogenic form accounts for more than 90% of cases: pain, numbness and tingling on the ulnar side of the hand and in fingers 4–5 (roots C8–T1, the lower trunk), worse with raising the arms, and sometimes wasting of the hand muscles. The diagnosis is clinical, helped by provocation tests and the response to injecting local anaesthetic into the anterior scalene muscle. First treatment is targeted physiotherapy for several months, and surgery (first rib resection and division of the scalene muscles) is for those who do not improve.

The venous form appears in an athletic young person after repetitive overhead arm activity: sudden swelling of the arm, cyanosis and prominent veins over the shoulder and chest — effort thrombosis of the subclavian vein. Diagnosis is by duplex or venography, and treatment includes catheter-directed thrombolysis, anticoagulation and then first rib resection to relieve the compression, otherwise the thrombosis recurs. The arterial form (about 1%) is usually linked to a cervical rib or an abnormal first rib, causing stenosis, a subclavian artery aneurysm and emboli to the fingers; work-up is CTA, and treatment is resection of the rib (cervical and first) and arterial repair, together with removal of emboli.

It is important to distinguish carpal tunnel syndrome and cervical radiculopathy, which also cause hand numbness but in a different distribution. In all types surgery is done through an axillary (transaxillary) or above-the-clavicle (supraclavicular) approach, depending on the type and site of compression, and its aim is to clear the narrow passage between the rib and the clavicle.

Key points

• More than 90% neurogenic.
• Neurogenic — physiotherapy first.
• Venous — thrombolysis and first rib resection.
• Arterial — cervical rib, emboli, surgery.
• Roots C8–T1 — ulnar side.

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Sources

• SVS reporting standards for thoracic outlet syndrome, 2016 — Definitions and diagnostic criteria
• Rutherford's Vascular Surgery and Endovascular Therapy, 10th edition (2022) — Thoracic outlet syndrome
• Shields' General Thoracic Surgery, 8th edition (2019) — Thoracic outlet syndrome

Sources are given for further reading; the text is written afresh and not copied from them.

Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.