2. Types of TOS

There are three types of thoracic outlet syndrome, but all three consist of a narrowed thoracic outlet space and scar formation.

  • Neurogenic TOS is the most common, occurring in about 90% of cases. It develops when there is compression of the nerves in the neck that lead to the arm.
  • Venous TOS happens when a vein is compressed and causes a blood clot in the upper body. Only about five percent of cases receive this diagnosis.
  • Arterial TOS is the rarest type of TOS. It is caused by the compression of an artery.
  • Sometimes, venous and arterial TOS occur together, causing vascular thoracic outlet syndrome.
venous blood clot Daft_Lion_Studio / Getty Images


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