• Clinical science

Thoracic outlet syndrome


Thoracic outlet syndrome (TOS) is an umbrella term for conditions involving the compression of neurovascular structures (e.g., the brachial plexus or the subclavian artery or vein) as they pass from the lower neck to the armpit. Causes include trauma, tumors, or the presence of a cervical rib. Neurogenic TOS is the most common type and involves the compression of the brachial plexus, leading to neck pain and numbness and tingling in the fingers. Arterial TOS involves compression of the subclavian artery and presents with pain, pallor, coldness, and pulselessness in the affected arm, especially during overhead activities. Venous TOS results in pain, cyanosis, and swelling of the arm. Imaging techniques such as duplex sonography, X-ray, MRI, or electrodiagnostic testing are used to detect the cause of TOS. Mild symptoms should be treated with pain medication and physical therapy. Surgical resection of the causal structures might become necessary in the case of progressive neurologic dysfunction or acute vascular insufficiency.


  • Compression of subclavian vessels and the lower trunk
    • Physical trauma (e.g. hyperextension neck injuries)
    • Repetitive motion of the abducted and externally rotated shoulder; (e.g. tennis; , baseball; , swimming, repetitive throwing, carrying heavy objects overhead)
    • Structural abnormalities


Clinical features

Swelling and venous distention in the arm may be a sign of venous thrombosis of the arm!




  • In mild cases: physical therapy; , weight reduction, NSAIDs, thrombolytics with continued anticoagulation in the case of venous thrombosis
  • In cases of acute vascular insufficiency or progressive neurologic dysfunction, or if conservative treatment fails: thoracic outlet decompression surgery
    • Transaxillary resection of the cervical rib or first rib
    • Angioplasty or venous or arterial bypass for severely narrowed vessels