Do you experience numbness or tingling in your arm, especially when lifting something overhead or holding your phone for a long time? Or perhaps you notice weakness in your fingers for no obvious reason? These symptoms are often attributed to something else — the neck, the wrist, or even the heart — when the true cause may lie in a problem that is relatively little known to the general public: Thoracic Outlet Syndrome.
This article is not a substitute for a personalised assessment by a specialist. Its aim is to give you useful information so that you can better understand your symptoms and know when to seek help.
What is Thoracic Outlet Syndrome?
The "thoracic outlet" is the space between the collarbone, the first rib, and the muscles of the neck. Running through this narrow passage are nerves (the brachial plexus), arteries, and veins that serve the arm.
When these structures become compressed — for whatever reason — a collection of symptoms affecting the arm, shoulder, or neck can develop. This is known as Thoracic Outlet Syndrome (TOS).
What forms does it take?
The syndrome is generally divided into three forms depending on which structure is being compressed:
• Neurogenic form: The most common. The nerves of the brachial plexus are compressed, causing numbness, tingling, or weakness in the arm and fingers.
• Venous form: Compression of the subclavian vein. The most typical presentation is swelling and heaviness in the arm, particularly after exercise.
• Arterial form: The rarest and most serious. It may be accompanied by pallor, a cold arm, or severe pain. It requires immediate medical assessment.
The vast majority of people have the neurogenic form, which responds well to conservative management.
What symptoms should you look out for?
Symptoms can vary from person to person, but the most characteristic ones include:
- Numbness or tingling in the arm, often on the side of the ring finger and little finger
- Pain in the shoulder, neck, or chest that worsens with movement
- Weakness in your grip or difficulty with fine movements
- Symptoms that worsen when you raise your arms overhead (e.g. reaching a shelf, getting dressed, driving)
- A sensation of the arm "falling asleep" at night
If your symptoms remind you of those associated with neck pain or shoulder pain, a combined assessment is important — the two problems can co-exist.
Why does it occur — Who is most at risk?
There is not always a single cause, but certain factors appear frequently:
- Poor posture: A forward head position, a rounded upper back, and drooping shoulders narrow the space of the thoracic outlet.
- Repetitive overhead movements: Electricians, painters, musicians, and swimmers.
- Muscle imbalances: Tight scalene or pectoralis minor muscles combined with weak shoulder blade stabilisers.
- Trauma: Collarbone fractures or a blow to the shoulder can alter the geometry of the area.
- Anatomical variations: Less commonly, a cervical rib (an extra rib at the neck) may contribute to the compression.
In today's world, prolonged desk work or remote working — particularly with poor ergonomics — is a growing risk factor. If remote working is relevant to you, take a look at our related article.
How is it diagnosed?
There is no single definitive test for TOS. Assessment is based on a combination of:
- A detailed history and analysis of symptoms
- Clinical tests (e.g. Roos test, Adson test, ULNT) performed by a physiotherapist or doctor
- Imaging investigations (cervical MRI, vascular ultrasound) to rule out other conditions
- Electromyography (EMG) in selected cases
Differentiating it from Carpal Tunnel Syndrome or a cervical disc herniation is crucial, as the symptoms can be very similar.
How does physiotherapy help?
In most cases of neurogenic TOS, conservative management with physiotherapy is the first line of treatment. A personalised programme may include:
- Postural correction: Strengthening exercises for the shoulder blade stabilisers and stretches for tight muscles (scalenes, pectoralis minor).
- Manual therapy and mobilisation techniques: Improving mobility of the cervical and thoracic vertebrae, which are often restricted. Chiropractic care can effectively complement physiotherapy.
- Neural mobilisation: Gentle techniques that help the nerve to "glide" freely through the surrounding tissues.
- Ergonomics education: Correct workstation set-up and proper posture during everyday activities.
- Home exercises: Gentle, progressively advanced exercises to be carried out between sessions.
In many cases, home visit physiotherapy can be particularly convenient, especially when travelling worsens symptoms — or simply when daily life leaves no time to travel to a clinic.
What can you do at home?
Before starting any exercise, it is important to be assessed by a specialist. However, some general principles that tend to help:
- Avoid sustained positions with your arms raised overhead or behind your head.
- Take short breaks during computer work — get up every 40–50 minutes.
- Pay attention to your sleeping position: avoid sleeping with your arm tucked under your pillow or your head.
- Wear a rucksack rather than a shoulder bag so that the weight is distributed evenly.
- If you notice a sudden worsening, coldness, or a change in colour in your arm, seek medical assessment promptly.
When should you be concerned?
Certain signs require prompt medical assessment — not simply an appointment with a physiotherapist:
- The arm becomes cold, pale, or bluish
- Severe pain that came on suddenly
- Significant weakness or loss of sensation over a short period of time
- Swelling or a change in the colour of the veins in the arm or shoulder
These may indicate arterial or venous involvement requiring urgent management. In any other situation, do not leave your symptoms to "go away on their own" for months — timely assessment makes a great deal of difference.
If you would like to discuss your symptoms, you are welcome to get in touch with us for an initial assessment.