How could TOS affect me?

In TOS, the nerves to the arms (called the brachial plexus), the subclavian artery and the subclavian vein may be squeezed as they exit the thoracic outlet. If the nerves are affected, the condition is called neurological TOS (nTOS). Similarly, if the artery or vein are affected, the condition is classified as arterial TOS (aTOS) or venous TOS (vTOS) respectively. They may occur in combination too. The manifestations may be present all the time or intermittently especially with certain positions of the neck or arm.

This compression may arise due to:

  1. Abnormal structure or arrangement (congenital abnormal anatomy)
  2. Excessive size of muscles/ ligaments (acquired hypertrophied structures)
  3. Trauma or other pathology (acquired abnormal anatomy)



What might happen if left alone:

Some patients do not ever have any symptoms.

In mild cases, the condition may not worsen if appropriate conservative measures are taken. Patients who have TOS of moderate severity may worsen over time and durable reversal can be achieved by surgical decompression. Getting older with less physical activity may improve symptoms as the muscles shrink with age.0

If compression is excessive, long term and irreversible damage to the nerves can occur. The pain, numbness and wasting may be permanent. Surgical treatment may still be worthwhile to prevent worsening. Frequently, decompression of the nerves results in a varying degree of improvement although some patients report no change. In the vein, the repeated compression and trauma might result in blockage (also known as subclavian vein thrombosis or Paget-Schröetter’s Syndrome). Compression of the artery may cause clots to form and travel down to the hand, the artery could become scarred and narrow, or even become excessively weakened (known as aneurysm formation). Although not life threatening in itself, the severe forms of TOS can result in significant suffering and reduction in quality of life.

Contacting Us


The Small Print

Mr Colin Chan
Consultant Vascular Surgeon
Wirral University Teaching Hospital
Wirral CH49 5PE

Mrs Louise Rule
Wirral University Teaching Hospital
Wirral CH49 5PE

(+44 151 604 7530)


Spire Wirral Hospital
Holmwood Drive
Wirral CH61 1AU

(+44 151 929 5181)

Spire Manchester Hospital
170 Barlow Moor Road
Manchester M20 2AF

(+44 161 447 6600)