What are the signs of thoracic outlet syndrome?

Signs of Thoracic Outlet Syndrome

The primary signs of thoracic outlet syndrome (TOS) include arm pain, swelling, fatigue, paresthesias, weakness, and hand discoloration, with specific manifestations depending on whether the condition is neurogenic, arterial, or venous in nature. 1

Types of Thoracic Outlet Syndrome and Their Signs

Neurogenic TOS (Most Common)

• Patients typically present with upper extremity sensorimotor symptoms that are often exacerbated by movement 2
• Symptoms include pain, numbness, tingling, or weakness in the arm, particularly with shoulder or neck movement 3
• Symptoms may worsen with overhead arm positions or repetitive motions 4

Venous TOS (vTOS)

• Characterized by compression of the subclavian vein in the thoracic outlet 5
• Signs include arm swelling, discoloration, and visible collateral veins 1
• Venous compression is often demonstrated during arm abduction on imaging studies 6
• May lead to upper limb deep vein thrombosis requiring anticoagulation 7

Arterial TOS (aTOS - Least Common)

• Results from compression of the subclavian artery 5
• Clinical signs include pallor, arm claudication, and coolness of the affected arm 8
• In severe cases, can lead to acute limb-threatening ischemia 8
• Often associated with repetitive overhead arm motion, particularly in athletes 8

Physical Examination Findings

• Provocative maneuvers that reproduce symptoms are key diagnostic indicators 8
• Compression may occur in distinct anatomical spaces:
  • Costoclavicular triangle (between clavicle, anterior scalene muscle, and first rib) 5
  • Interscalene triangle 5
  • Pectoralis minor space 5
• Postural abnormalities may be present and contribute to symptoms 3
• Hypertrophy of neck musculature may be observed in some cases 3

Diagnostic Imaging Findings

• Chest radiography may reveal osseous abnormalities such as cervical ribs or first rib anomalies 5
• MRI with contrast can be useful for diagnosing neurogenic TOS 5
• For arterial TOS, CTA with IV contrast, MRA, or ultrasound duplex Doppler is recommended 5
• For venous TOS, catheter-based venography, CT venography, MR venography, or ultrasound duplex Doppler studies are recommended 6
• Venous compression during arm abduction on imaging must be correlated with clinical symptoms, as this finding can be present in asymptomatic individuals 6

Common Pitfalls in Diagnosis

• TOS is not a diagnosis of exclusion - there should be evidence of a physical anomaly that can be corrected 1
• No single test has high sensitivity and specificity for diagnosing TOS 4
• Venous compression on imaging alone is insufficient for diagnosis without corresponding symptoms 6
• Symptoms may overlap with other conditions, leading to delayed or missed diagnosis 2
• There is currently no uniform classification system across medical subspecialties, limiting standardized diagnosis 2

Risk Factors

• Congenital abnormalities such as cervical ribs or fibrous bands 1
• Neck trauma 1
• Repeated work stress or overhead motions 3
• Athletic activities involving throwing or weightlifting 4
• Abnormal posture 3