Arterial Thoracic Outlet Syndrome (ATOS)

The least common form of Thoracic Outlet Syndrome. This condition threatens the arm and hand due to blockages in the artery that go to arm and hand. ATOS is typically related to the presence of an extra rib and repetitive use of that extremity.

Symptoms of Arterial Thoracic Outlet Syndrome

  • Sudden pain and color changes in fingers (when this occurs to an otherwise healthy and young person who does not have history of irregular heart beat or unusual clotting disorders).
  • Mass that pulses above collar bone, indicating aneurysm of subclavian artery.  
  • May also have neck pain, numbness and tingling in the extremity similar to neurogenic thoracic outlet syndrome.

Cause of Arterial Thoracic Outlet Syndrome

Most patients with ATOS have a congenital cervical rib. This rib sits above the 1st rib and causes compression of subclavian artery (the artery that provides blood supply to arm and hand). With repetitive injury the artery can form aneurysm (abnormal dilation of the artery) that either shower clots to the hand or clots off completely. This condition, if not treated immediately, could lead to limb loss. The medical image below is from one of our patients. The arrow shows the location of aneurysm and extra rib.


ATOS – medical image provided by G. Sheng, MD, Vascular Surgeon, St.Vincent Medical Group.


These photos taken during ATOS surgery show the aneurysm and what the clot looks like inside the aneurysm. Photos provided by G. Sheng, MD, Vascular Surgeon, St. Vincent Medical Group.

Treatment of Arterial Thoracic Outlet Syndrome 

The treatment of ATOS is immediate removal of the extra rib, removal of aneurysm, and restoration of blood flow to hand.