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Thoracic Outlet Syndrome

What is TOS?

Thoracic outlet syndrome is a group of disorders that occur when the blood vessels or nerves in the space between the clavicle and the first rib (thoracic outlet) become compressed. This can cause pain in the shoulders and neck, and numbness in the fingers.



Symptoms vary depending on which nerve is compressed.

Neurological thoracic outlet syndrome is characterised by compression of the brachial plexus. The symptoms include:

  • Muscle wasting at the base of the thumb
  • Numbness or tingling in thearm or fingers
  • Pain or aching in the neck,shoulder or hand
  • Grip weakness

Vascular thoracic outlet syndrome occurs due to compression of the veins or arteries under the clavicle.

Symptoms include:

  • Discolouration of the hand
  • Arm pain or swelling (due to blood clots)
  • Blood clots in the vessels in the upper body
  • Lack of colour in the fingers or hand
  • Weak or lack of pulse in the affected arm
  • Cold fingers, hands or arms
  • Fatigue in the arm, after activity
  • Numbness or tingling in the fingers
  • Arm or neck weakness
  • Throbbing lump around the clavicle

Woman pain


What causes TOS?

Symptoms occur due to compression of the blood vessels and nerves in the space between the collarbone. The compression occurs for various


  • Trauma eg. Car accident
  • Repetitive activity eg. Job related, sport related
  • Anatomical defects such as a cervical rib – this narrows the space for the blood vessels and nerves
  • Poor posture – a round shoulder, kyphotic posture narrows the thoracic outlet and tightens the muscles at the front of the neck
  • Pressure on the joints – this can occur from carrying a backpack or being overweight
  • Pregnancy – hormones released in pregnancy cause ligaments around joints to relax. This can include the joints around the thoracic outlet



Our physiotherapists will perform a thorough

assessment to determine the onset of symptoms and establish a cause for the injury. They use various provocation tests designed to reproduce the symptoms and rule out other conditions which may have similar symptoms.

To confirm a diagnosis the physio may refer for an

X ray, scan, EMG or nerve conduction study.



Physiotherapy is the first line of treatment for neurogenic thoracic outlet syndrome. It aims to take pressure off the blood vessels and nerves to decrease pain and increase function. Manual therapy will help in releasing muscle contracture and joint stiffness. Home exercise programmes are then used to strengthen the shoulder, open the thoracic outlet, improve movement, mobilise the neural structures and enhance posture.



Hands on back