Thoracic Outlet

apertura thoracis superior

The thoracic outlet is the superior aperture of the thorax bounded by the first rib, the clavicle, and the manubrium, through which pass the brachial plexus, the subclavian artery and vein, and the phrenic nerve. The scalene triangle (anterior scalene, middle scalene, first rib) subdivides the space: the subclavian vein passes anterior to the anterior scalene, and the brachial plexus and subclavian artery pass posterior to it.

Region: Neck

Clinical Relevance

Clinical Notes

Thoracic outlet syndrome (TOS) occurs when the neurovascular structures are compressed in the thoracic outlet. Neurogenic TOS (most common, affects brachial plexus) produces arm pain, paraesthesias, and weakness. Vascular TOS affects the subclavian artery (Raynaud, distal emboli) or vein (effort thrombosis, Paget-Schroetter syndrome). The EAST test, Adson test, and costoclavicular manoeuvre are provocative tests. Surgical treatment involves first rib resection with scalenectomy.

Pathology

Common Injuries & Conditions

Paget-Schroetter Syndrome (Effort Thrombosis)

Subclavian vein compression in the thoracic outlet by the first rib-clavicle-costoclavicular ligament complex during overhead activities produces axillosubclavian vein thrombosis with acute arm swelling, cyanosis, and distended collateral veins; managed by thrombolysis followed by first rib resection to prevent recurrence.