Thoracic Outlet Syndrome: Symptoms, Causes & Treatment

Thoracic outlet syndrome is a group of problems that happen when blood vessels or nerves in the thoracic outlet are squeezed. The thoracic outlet is the space between your collarbone (clavicle) and your first rib. It can cause pain in the shoulders and neck and numbness in the fingers.

Common causes include injury in a car accident and repeated strain from work or sport. An old injury can cause it years later. Sometimes doctors cannot find the cause.

Treatment usually involves physiotherapy and pain relief. Most people improve with these non-surgical treatments. Sometimes your doctor may recommend surgery.

Symptoms

There are three types of thoracic outlet syndrome.

Neurogenic (neurological) thoracic outlet syndrome. The brachial plexus is squeezed. This is a network of nerves from the spinal cord that control movement and feeling in the shoulder, arm and hand. Most cases are this type.
Vascular thoracic outlet syndrome. One or more of the arteries and veins under the collarbone (subclavian vessels) are squeezed.
Non-specific thoracic outlet syndrome. This is also called disputed or common thoracic outlet syndrome. Some doctors do not think it exists, and others say it is common. People with this type have long term pain around the thoracic outlet, but the exact cause of the pain cannot be found.

Symptoms depend on which structures are squeezed. When nerves are squeezed, symptoms of the neurogenic type often include:

Numbness or tingling in your fingers
Pain in your shoulder and neck
Ache in your arm or hand
Weakening grip

The vascular type (veins and arteries squeezed) can cause:

Discolouration of your hand (bluish colour)
Subclavian vein thrombosis
Arm pain and swelling, possibly due to blood clots
Throbbing lump near your collarbone
Pale colour (pallor) in one or more fingers or the whole hand
Tiny black spots (infarcts) on your fingers

When to see your doctor

See your doctor if you often have any of these signs and symptoms.

Causes

The cause is squeezing of the nerves and blood vessels in the thoracic outlet, just under the collarbone. What causes the squeezing can vary. It can include:

Anatomical defects. Some people are born with a cervical rib (an extra rib above the first rib) or an unusually tight fibrous band joining the spine to a rib.
Poor posture. Drooping the shoulders or holding the head forward can squeeze the thoracic outlet.
Trauma. An injury, such as a car accident, can cause changes inside the body that squeeze the nerves in the thoracic outlet. Symptoms often start some time after the accident.
Repetitive activity. Doing the same movement over and over can wear on the body over time. You may notice symptoms if your job needs you to repeat a movement, such as typing for long periods, working on an assembly line or lifting things above your head again and again. Athletes such as baseball pitchers and swimmers can also develop it from years of repeated movements. Carrying heavy loads low on your body, rather than against your chest, can also cause symptoms.
Pressure on your joints. Obesity puts extra stress on your joints. So does carrying an oversized bag or backpack.
Pregnancy. Joints loosen during pregnancy, so signs of thoracic outlet syndrome may first appear then.

Risk Factors

Women are at higher risk, especially women with poor posture or weak muscles.

Investigations

It can be hard to diagnose because symptoms and their severity vary a lot between people. Your doctor may first examine you for outward signs, such as a dip in the shoulder, a pale arm or limited movement.

Your doctor will ask about your job, your medical history and your symptoms. They may do provocation tests, which are designed to bring on your symptoms. These tests can help find the cause and rule out other conditions with similar symptoms.

Common provocation tests include:

Adson’s manoeuvre. You turn your head towards the sore shoulder and stretch your arm, neck and shoulder slightly away from your body. As you breathe in, your doctor checks the pulse at the wrist of your stretched arm. If the pulse weakens or your symptoms come on, the test is positive and may point to thoracic outlet syndrome. False positives are common, so your doctor may repeat the test on the other side.
Wright test. Sitting, you hold your arm up and back (hyperabduction) and turn it outwards, with your doctor’s help. Your doctor checks whether your pulse weakens and whether your symptoms come on, as in Adson’s manoeuvre.
Roos stress test. Sitting, you hold both elbows at shoulder height and push your shoulders back. Then you open and close your hands over and over for several minutes. If your symptoms come on, or your shoulders feel heavy and tired, this can point to thoracic outlet syndrome.

To confirm the diagnosis, your doctor may also order one or more of these tests:

X-ray. An X-ray of the area may show an extra rib (cervical rib) and can rule out other causes of your symptoms.
Magnetic resonance imaging (MRI) scan. An MRI is painless. It uses a magnetic field and radio waves to make detailed pictures of soft tissues. These can show where the brachial plexus nerves or the subclavian artery are squeezed, and why. The scans may also show problems you were born with, such as a fibrous band joining the spine to a rib, or a cervical rib.
Electromyography (EMG). This test lets your doctor see and hear how your muscles and nerves are working. A small needle electrode is put through the skin into muscles near your symptoms. The electrical activity is shown on a screen and can be heard through a speaker.
Nerve conduction study. This test measures how fast signals travel along a nerve. Doctors use it to check for nerve damage. Small electrodes are placed on the skin over the area, and a tiny electrical current is sent to the nerves in your thoracic outlet. A computer picks up the signals from the nerves and muscles, and a doctor trained in electrodiagnostic medicine reads the results.

Complications

If left untreated, thoracic outlet syndrome can cause permanent nerve damage. However, surgery for it is risky. The operation involves cutting a muscle in the neck and removing part of the first rib or repairing the brachial plexus nerves. So most doctors first suggest treatment without surgery.

Treatment

In most cases, treatment without surgery works, especially if the condition is found early. It may include:

Physiotherapy. You learn exercises that strengthen the shoulder muscles to open up the thoracic outlet, improve movement and improve posture. Done over time, these take pressure off the blood vessels and nerves.
Relaxation. Relaxation techniques such as deep breathing stop you tensing your shoulders and remind you to keep good posture.
Medicines. Your doctor may prescribe pain relief, muscle relaxants and anti-inflammatory drugs (aspirin or ibuprofen) to reduce inflammation and relax muscles.

If these treatments do not help, or you have signs of serious nerve damage, worsening muscle weakness or disabling pain, your doctor may suggest surgery. Surgery may also be advised for true neurogenic thoracic outlet syndrome, where it is often the only option.

Surgical options

Surgery usually relieves the pain of thoracic outlet syndrome. It is often less successful for muscle weakness, especially if the condition has gone untreated for a long time.

A thoracic or vascular surgeon does the operation. All surgical options carry a significant risk of injury to the brachial plexus. The most common operations are:

Anterior supraclavicular approach. This repairs squeezed blood vessels. The surgeon makes a cut just above the collarbone to reach the brachial plexus area. They look for signs of injury or fibrous bands pressing near the first (top) rib, and repair any squeezed blood vessels.
Transaxillary approach. The surgeon makes a cut in the chest to reach the first rib and removes part of it to relieve the pressure. This gives easy access to the first rib without disturbing the nerves or blood vessels. But access to the nerves and vessels is limited, and most fibrous bands and cervical ribs that may be causing the problem are hidden behind them.

Looking After Yourself

Your doctor or physiotherapist will show you exercises to do at home to strengthen and support the muscles around your thoracic outlet. To avoid extra stress on your shoulders and these muscles:

Maintain good posture
Take frequent breaks at work
Practise relaxation techniques

Coping and support

Many other conditions can cause the same symptoms, which makes diagnosis hard. Many people have symptoms for years before they are diagnosed, which can cause stress and frustration.

If your symptoms continue and you have no diagnosis, talk to your doctor about your concerns. A second opinion may put your mind at ease and let you focus on getting better.

Seeking Advice

Your Family Doctor (GP)

Your family doctor can diagnose your problem and help treat it. They can:

tell you about your problem
advise you of the best treatment methods
prescribe you medications
and if necessary, refer you to Specialists (Consultants) for further treatment

You will probably start with your GP. Your doctor may later send you to a doctor who specialises in vascular conditions or vascular surgery.

Appointments can be short and there is often a lot to cover, so it helps to be well prepared. Here is some information to help you get ready.

Bring along information about yourself

It helps your doctor if you bring:

A list of your medications, including the name and dosage.
Information about your medical problems and past treatment
Previous investigation results, such as X-rays and blood tests.

Prepare a list of questions for your doctor

Ask when you book if there is anything you need to do before the appointment.
Write down any symptoms you have, even ones that seem unrelated. Be as specific as you can. Say which part of your body is affected and use words to describe the discomfort.
Write down important personal details, such as injuries like a car accident or a work injury. Include them even if they happened years ago. Also note any repeated physical activities you do or did at work, in sport or in hobbies.
List your main medical details, including other conditions you are treated for and any prescription or over the counter medicines or supplements you take.
Take a family member or friend if you can. It is hard to take in everything said during an appointment, and someone with you may remember what you missed.
Write down questions to ask your doctor.

Your time with your doctor is limited, so a list of questions helps you make the most of it. List your questions from most to least important in case time runs out.

Some basic questions to ask your doctor:

What is likely causing my symptoms or condition?
Are there any other possible causes for my symptoms or condition?
Do I need any special tests or investigations?
What treatment approach do you recommend?
How likely are non-surgical treatments to improve my symptoms?
If conservative treatments aren’t effective, is surgery an option? Why or why not?
Is there anything I can do to prevent a recurrence of this problem?
Will I need to change my job?
Do I need to limit or give up other activities that may be causing my symptoms?
If you’re recommending weight loss, how much weight do I need to lose to notice an improvement in my symptoms?
I have these other health conditions. How can I best manage them together?
Should I see a specialist? What will that cost, and will my insurance cover seeing a specialist?
Are there any fact sheets or printed information that I can take home with me to read? Are there any reliable websites that I can visit?

As well as your prepared questions, ask any time you do not understand something.

What to expect from your doctor

Your doctor will probably ask you a number of questions. Being ready to answer them leaves more time to talk about what you want to cover. Your doctor may ask:

When did you first begin experiencing symptoms?
How would you describe your symptoms?
Have your symptoms changed or gotten worse over time?
Where does your pain or discomfort seem to start? Where does it travel from there?
Does the pain or numbness worsen when you lift your arms overhead?
Does anything else seem to worsen or improve your symptoms?
What activities do you perform on your job?
Do you or did you play sports?
What are your hobbies or most frequent recreational activities?
Have you been diagnosed or treated for any other medical conditions? When?

What you can do in the meantime

While you wait for your appointment, you can try an NSAID such as aspirin or ibuprofen. Good posture and avoiding repeated movements and heavy lifting may also help.

Prevention

If left untreated for years, thoracic outlet syndrome can cause permanent nerve damage. It is important to deal with symptoms early, or better still to prevent the problem. If you are prone to it, avoid repeated movements and heavy lifting. If you are overweight, losing weight can prevent or ease symptoms.

Even if you have no symptoms, avoid carrying heavy bags over your shoulder, because this adds pressure to the thoracic outlet. Stretch every day and do exercises that keep your shoulder muscles strong.

F.A.Q. | Frequently Asked Questions

What is being compressed in thoracic outlet syndrome?

The nerves and blood vessels that run from the neck to the arm pass through a narrow space between the collarbone, the first rib and the neck muscles. Tight muscles, an extra rib, poor posture or an old collarbone fracture can narrow this space and squeeze them.

Why is it hard to diagnose?

The symptoms, such as aching, tingling and weakness in the arm and hand, overlap with neck problems, carpal tunnel syndrome and shoulder conditions, and there is no single test that confirms it. Diagnosis rests on the pattern of symptoms, examination and ruling out other causes.

What is the treatment?

For the common nerve type, physiotherapy to improve posture, open up the chest and strengthen the shoulder blade muscles, together with changes to work set up, settles most people over 3 to 6 months. The rarer blood vessel types, with swelling or colour change of the arm, need urgent assessment and sometimes surgery.

Does surgery help?

Surgery to remove the first rib or release the tight neck muscles is kept for people with clear blood vessel compression or nerve symptoms that have not improved after a long trial of physiotherapy. Results are good for the blood vessel types and more mixed for the nerve type.