Thoracic Outlet Syndrome

Thoracic outlet syndrome (TOS) is a group of rare disorders that happen due to the compression of nerves or blood vessels in your lower neck and upper chest. The “thoracic outlet” is the opening between your collarbone (clavicle) and first rib. Your brachial plexus (nerves that cross from your neck to your armpit), subclavian artery and subclavian vein pass through this opening.

Normally, your thoracic outlet has enough room for these nerves and blood vessels. But injuries or certain differences in anatomy can crowd this outlet. When that happens, bones or muscles in your chest press on the nerves or blood vessels within this space. This compression can cause pain, abnormal sensations (paresthesia) and other symptoms in your upper body. The wide range of symptoms, which could point to many possible problems, can delay diagnosis.

Treatments like physical therapy and pain medications help most people. But you may need surgery if those methods don’t work or if TOS gets in the way of normal blood flow.

Types of thoracic outlet syndrome

Types of TOS vary by what’s compressed:

• Neurogenic thoracic outlet syndrome: This is compression of your brachial plexus, the nerves that come out of your neck, through its lower part and to your arm. This is by far the most common type. People often get this from repetitive stress injuries (from sports) and neck trauma (like whiplash).
• Venous thoracic outlet syndrome: This is compression of your subclavian vein. You usually feel symptoms in the arm you use most.
• Arterial thoracic outlet syndrome: This is compression of your subclavian artery. It’s the rarest type of TOS. It usually happens due to differences in anatomy that you’re born with (like a cervical rib).

The term “vascular thoracic outlet syndrome” refers to the venous or arterial types.

Symptoms of thoracic outlet syndrome

Thoracic outlet syndrome symptoms vary by type. They affect your upper body (neck, upper chest, shoulder, arm or hand), typically on one side.

Some people confuse thoracic outlet syndrome pain (a dull ache) with angina. Angina is chest pain you feel when your heart muscle doesn’t get enough oxygen. It can be a sign of a heart attack. But there are some important differences:

• TOS pain doesn’t occur or get worse when you walk, while angina typically does. Angina can also have other symptoms, like shortness of breath, heart palpitations and lightheadedness.
• TOS pain usually gets worse when you raise the affected arm. This doesn’t happen with angina.

In addition to pain, thoracic outlet syndrome symptoms may include:

• Tingling or “pins and needles”
• Numbness
• Weakness (if you also have slurred speech and drooping on one or both sides of your face, it could be a stroke)
• Swelling or heaviness
• Skin color changes (skin that looks pale or blue)
• Skin that feels cool to the touch
• Slow-healing sores on your fingers

The symptoms you feel can vary depending on the type of thoracic outlet syndrome you have. Here’s a breakdown:

Thoracic outlet syndrome causes

Healthcare providers divide the causes of TOS into three main groups:

• Congenital: These are differences in your anatomy that you’re born with. For example, there may be something unusual about your ribs, neck muscles or nearby ligaments. These variations may put pressure on the nerves or blood vessels in your thoracic outlet.
• Traumatic: These are sudden injuries that affect your neck and upper chest area. Common examples are injuries from car accidents, like whiplash.
• Functional: These are actions you do over and over that irritate or injure the structures in your thoracic outlet. Vigorous arm movements are a common culprit among athletes (like baseball players and swimmers). Repeated overhead lifting is another example.

A congenital issue may make you more likely to get TOS. But you may not feel any symptoms until you have trauma to your neck from a sudden injury or chronic overuse.

Risk factors

Many cases of this syndrome happen in people between ages 20 and 50. Sources disagree about which type is more common among males vs. females. You may face a higher risk of developing thoracic outlet syndrome if you:

• Play sports that involve repeated arm or shoulder movement (like baseball, swimming, golf or volleyball)
• Lift weights
• Have an injury to your neck or back

How to lower your risk

Many causes of TOS are beyond your control. If your job requires heavy lifting or overhead arm movements, talk to a healthcare provider about exercises that can help lower your risk of injury.

Complications of this condition

Without treatment, thoracic outlet syndrome can lead to serious complications, including:

• Axillo-subclavian vein thrombosis
• Chronic arm swelling and pain, especially in people with venous TOS
• Gangrene
• Open sores (ischemic ulcers) on your fingers from reduced blood flow
• Permanent nerve damage
• Pulmonary embolism

How doctors diagnose this condition

Healthcare providers diagnose TOS by performing a physical exam and reviewing your medical history. Your exam may include thoracic outlet syndrome testing, like an upper-limb tension test or an elevated arm stress test.

For these tests, you may lift your arms, tilt your head and clench your fists. Your provider will see which movements trigger pain or other symptoms. The results can help with a diagnosis. Providers may inject lidocaine into your muscles to relax them.

Providers order lab and imaging tests as needed to confirm TOS and rule out other causes of symptoms. These tests help your provider find atypical anatomy, check blood flow in blood vessels, see how well your muscles and nerves work, and find the exact location of compression.

You may need one or more of the following thoracic outlet syndrome tests:

• Blood tests
• Chest X-ray
• Ultrasound
• Computed tomography (CT) of your chest, neck and/or spine
• Electromyography (EMG)
• Magnetic resonance angiography (MRA) of your blood vessels
• Magnetic resonance imaging (MRI) of your chest and/or spine
• Nerve conduction study

How is it treated?

Thoracic outlet syndrome treatments vary, depending on the type of TOS and symptoms. The goals of treatment are to reduce symptoms and prevent complications. Your provider will recommend the treatment option that’s right for you.

Possible treatments include:

• Physical therapy: This is the most common first treatment for neurogenic TOS. A physical therapist helps you move your neck and shoulders better. Physical therapy also strengthens your muscles and promotes better posture.
• Medications to relieve pain: Your healthcare provider may recommend over-the-counter pain relievers, like NSAIDs.
• Medications to prevent or break up blood clots: Thrombolytic therapy helps people with arterial or venous TOS. Medication through an IV line or catheter dissolves existing blood clots and prevents new ones from forming. Your provider may also prescribe anticoagulants.
• Injections: Your provider may inject botulinum toxin into muscles.
• Surgery: Most people with arterial or venous TOS need surgery. Some people with neurogenic TOS need surgery if other treatments don’t work. Surgeons may remove abnormal bone or tissue or repair problems with your blood vessels.

When should I see my healthcare provider?

Seek medical care if you have symptoms of TOS. Don’t wait for your symptoms to go away. In many cases, physical therapy and medicine can improve symptoms. But some people need surgery or other treatments to prevent serious complications. Your provider will recommend a treatment plan that’s best for your needs.

Call your provider if you have new or changing symptoms. They’ll tell you how often you need to come in for follow-ups and tests.

Questions to ask your provider may include:

• What type of thoracic outlet syndrome do I have?
• What’s the cause?
• What treatments do you recommend, and what’s the timing for them?
• What are the risks of treatment?
• What’s my outlook?

What can I expect if I have this condition?

Thoracic outlet syndrome can make it hard to perform daily tasks and do physical work. Early diagnosis and treatment can give you a better outcome. But sometimes, people don’t get a diagnosis until they see a vascular surgeon.

The outlook for people with thoracic outlet syndrome varies based on the type. Your healthcare provider is the best person to ask about what you can expect.

Is there anything I can do to feel better?

Follow your healthcare provider’s guidance on how to take care of yourself if you have TOS. They may recommend you:

• Avoid carrying heavy bags on your shoulder or lifting objects above your head.
• Work with a physical therapist.
• Do exercises at home to strengthen your muscles and improve your posture.
• Modify your daily activities to limit or avoid certain movements that cause symptoms.