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Thoracic Outlet Syndrome (TOS)

TOS is an uncommon conditions that results from a narrowing of the area where your collarbone and rib cage meet. In this area near the shoulder, the arm’s artery, vein, and nerves can be compressed causing various symptoms. This is a complicated diagnosis and evaluation by a Vascular Surgeon specialist is needed to differentiate this condition from other common conditions of the arm.

Arterial TOS: The artery is damaged and blood clots can fall down towards the hand causing tissue damage. Sometimes blood flow is restricted and can lead to early fatigue with arm use. Sometimes this is caused by an extra bone called a “cervical rib.”

Venous TOS: The vein is damaged and scarred from the tight space leading to blood clots in the arm. Signs and symptoms of this can be a swollen, purple and painful arm.

Nerve TOS: The arm nerves are compressed and this can sometimes cause scarring around the area. Signs and symptoms of this include pain, numbness/tingling, and early fatigue of the arm when doing upwards movements such as brushing your hair.

Some patient are born with this space being narrow. Most of the times, patients can develop TOS because they have jobs that involve a lot of upward arm movement. Some examples are those who work with high shelves, painters, or contractors. Even athletes such as volleyball or baseball players can develop TOS over time! Traumatic arm/shoulder injuries can also cause TOS.


If symptoms are mild, physical therapy can allow the compressed space between the collar bone and first rib to be relaxed and no surgery is required. If symptoms are more severe or continue despite physical therapy, a first rib resection can be performed to create more space and reduce the compressive effect of that narrow space. Due to the sensitive structures in that area, this procedure is performed by specially-trained Vascular Surgeons. Dr. Joyce Lu specializes in utilizing the axillary approach where the incision is well-concealed in the underarm area and this is favored for most patients whenever possible.

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