Understanding our thorax: Thoracic outlet syndrome

What is it? 

Thoracic outlet syndrome (TOS) is the compromise of neurovascular structures undergoing compression as they pass under the 1st rib to reach the arm. The structures that can be affected comprise the subdivisions of this pathology: the subclavian artery, the subclavian vein or the brachial plexus. 

  • Neurological TOS happens in 95-99% of the TOS cases. 
  • Vascular TOS (veins or arteries) happens 1-5% of the TOS cases. 

Who could have it?  

Some cases of TOS are associated with anatomical abnormalities such as having an extra cervical rib, congenital muscular abnormalities, or clavicular stiffness. 8% of the population has TOS and it is 3-4 times more frequent in women than men between 20-50 year olds. 

TOS can be caused by postural factors implicating pec shortening and drooping shoulders. Muscular imbalances are commonly seen in these cases. It can also be due to repetitive stress injuries or trauma to ribs or clavicles. Sports causing the most compression (abduction and external rotation) include but are not limited to overhead throwing (tennis, baseball, swimming). 


What does it look like ?  

  • Neurological TOS will often have mild pain between the neck and hands and sensory changes such as decreased sensation, decreased strength, feeling of heaviness in the arm, numbness, tingling or pins and needles. 
  • Vascular TOS will complain of pressure building in the whole arm, heaviness, change of colour in the arm or even temperature change, swelling in the arm. . 

How can physiotherapy help?  

The first line of treatment for TOS is the conservative route through physiotherapy as to decreasing symptoms, facilitating movements and educating. Things to work on include scapular control and positioning, releasing muscular tightness such as pectoralis, mobilising stiffness in joints nearby. 

If it cannot be fully managed by physiotherapy, especially for the Venous TOS, surgery might be recommended. There are several techniques such as the transaxillary approach, supraclavicular approach and infraclavicular approach. Of course, postoperative rehabilitation will be necessary to avoid scar tissue adhesions, bad positioning and the risk of continuing compressing structures and causing symptoms. 

For a more detailed rehabilitation treatment plan and exercise program, consult your physiotherapist.