Thoracic outlet syndrome (TOS) occurs when nerves or blood vessels are compressed by the rib, collarbone or neck muscles at the top of the outlet.



Types of thoracic outlet syndromes?


Neurogenic TOS occurs when the nerves leading from the neck to the arm (the brachial plexus) is compressed. More than 90% of cases are neurogenic.

  • Pain or weakness in the shoulder and arm
  • Tingling or discomfort in the fingers
  • Arm that tires quickly
  • Atrophy – shrinking and weakness – of the pad of the thumb, the muscle of the palm that leads to the thumb; this is quite rare


Venous TOS occurs when a vein is compressed, leading to upper body thrombosis. 5% of cases are venous.

  • Edema (swelling) of the arm, hand or fingers
  • Blueness of the hand and arm
  • Painful tingling in the hand and arm
  • Very prominent veins in the shoulder, neck and hand


Arterial TOS occurs when an artery is compressed. Only about 1% of cases are arterial.

  • Cold and pale hand
  • Pain in the hand and arm, especially during overhead motions of the arm
  • Embolism (blockage) of an artery in the hand or arm
  • Aneurysm of the subclavian artery

*Sometimes, the venous and arterial syndromes are known together as vascular thoracic outlet syndrome. *




  1. Cervical rib/Abnormal scalene muscles
    – an extra rib that grows from the cervical spine – the neck part of the spine which may grow on one side or both, and may reach down to attach to the first rib or may not be fully formed.
  2. Whiplash
  3. Body builder
  4. Repetitive overhead movement
  5. Extra fats around the neck
  6. Tumor in the neck


Prepared by

Leong Mei Ling

Your Physio Petaling Jaya 

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