Thoracic outlet syndrome

Background

Drawing of thoracic outlet syndrome.

The right brachial plexus with its short branches, viewed from in front. The Sternomastoid and Trapezius muscles have been completely removed, the Omohyoid and Subclavius have been partially removed; a piece has been sawed out of the clavicle; the Pectoralis muscles have been incised and reflected.

Anatomy of the thoracic outlet.

• Symptoms from compression of neurovascular bundle at thoracic outlet
• Neuro complications most common (95%), then venous compression (3%), and then arterial (1%)
• Scalene triangle most often involved area: borders are anterior scalene, middle scalene and first rib

Clinical Features

• Pain, numbness or weakness in upper extremity aggravated by elevating hands
  • Neck rotation, arm abduction or UE external rotation may elicit symptoms
• Sensory deficits common along T1 distribution
• Swelling, claudication pain & cyanosis with activity if venous compression
• Hand ischemia (pain, pallor, paresthesia, cold) if arterial compression
  • Almost always has cervical/anomalous rib
• May have tender scalene muscles
• Thrombus may develop from vascular compression

Differential Diagnosis

Shoulder and Upper Arm Diagnoses

Traumatic/Acute:

• Shoulder Dislocation
  • Anterior shoulder dislocation
  • Posterior shoulder dislocation
  • Inferior shoulder dislocation
• Clavicle fracture
• Humerus fracture
• Scapula fracture
• Acromioclavicular joint injury
• Glenohumeral instability
• Rotator cuff tear
• Biceps tendon rupture
• Triceps tendon rupture
• Septic joint

Nontraumatic/Chronic:

• Rotator cuff tear
• Impingement syndrome
• Calcific tendinitis
• Adhesive capsulitis
• Biceps tendinitis
• Subacromial bursitis
• Cervical radiculopathy

Refered pain & non-orthopedic causes:

• Referred pain from
  • Neck
  • Diaphragm (e.g. gallbladder disease)
• Brachial plexus injury
  • Rucksack paralysis
• Axillary artery thrombosis
• Thoracic outlet syndrome
• Subclavian steal syndrome
• Pancoast tumor
• Myocardial infarction
• Pneumonia
• Pulmonary embolism

Evaluation

• CXR
• Consider duplex ultrasound if venous/arterial compression suspected

Management

• Physical therapy as outpatient
• Treat embolus if present
• Consider interscalene injection

Disposition

• Home