Thoracic Outlet Syndrome

What Is Thoracic Outlet Syndrome? 

Thoracic outlet syndrome (TOS) occurs when the blood vessels or nerves in the area between your upper chest and lower neck get pinched or compressed. This space is called the thoracic outlet. The nerves and blood vessels in your thoracic outlet include the ones that exit your chest and extend into your arm. 

There are three types of TOS: 

• Neurogenic thoracic outlet syndrome is the most common type. It involves compression of the nerves leading from your neck to your arms (brachial plexus). 
• Venous thoracic outlet syndrome occurs when the vein that drains blood from your arm is compressed. 
• Arterial thoracic outlet syndrome is the least common and most serious type. It occurs when the arteries in your thoracic outlet are compressed. This compression can result in a blood clot that requires emergency surgery to restore circulation in your arm. 

Thoracic Outlet Syndrome Symptoms 

TOS symptoms depend on whether your nerves, arteries or veins are compressed. Generally, symptoms affect your shoulder, arm or hand. 

Neurogenic TOS symptoms

Nerve compression may cause: 

• Inability to use your arms 
• Muscle weakness or fatigue in your arm or hand 
• Numbness or tingling in your arm, hand or fingers 
• Pain or aching in your shoulder, arm or hand 

Venous TOS symptoms 

Vein compression may cause: 

• Arm or hand swelling 
• Discoloration in your arm or hand 
• Feelings of heaviness in your arm or hand 
• Pain in your arm or hand 

Venous thoracic outlet syndrome can also lead to blood clots. These blood clots may detach and travel to your lungs, causing a pulmonary embolism. 

Arterial TOS symptoms

Artery compression may cause: 

• Arm or hand pain or weakness 
• Cold arm, hand or fingers 
• Faint or no pulse in the affected arm 
• Paleness or bluish color in the hand or fingers 

Arterial thoracic outlet syndrome commonly results in a blood clot that blocks circulation in your arm and hand. It requires emergency surgery to restore blood flow and prevent limb loss. 

If you experience a weakened pulse in one arm or an inability to use one of your hands, go to the emergency department or call 911. 

Causes of Thoracic Outlet Syndrome

Each type of TOS has different causes: 

• Neurogenic TOS is usually the result of an injury such as whiplash or a bad fall. It can also arise from frequent, intense, repetitive movements, including those performed during sports or jobs that require overhead lifting. Sometimes it also develops as the result of poor posture, such as craning your neck to look at a screen. 
• Venous TOS most commonly develops because of hypertrophy in your upper body. Hypertrophy is muscle growth, usually caused by weightlifting or other intensive workouts. 
• Arterial TOS typically relates to developmental differences that were present at birth. For example, some people are born with an extra rib that can increase the risk of compression. 

Diagnosing Thoracic Outlet Syndrome

Diagnosing TOS starts with a physical exam. Depending on the type you have, your vascular surgeon may also use one or more tests, such as: 

• Arteriogram or venogram: Your vascular surgeon inserts a small, flexible tube (catheter) through a blood vessel in your groin and directs it to the arteries or veins in your thoracic outlet. They use imaging and a special dye to check for artery or vein compression. 
• Duplex ultrasound: This test uses sound waves to look at your blood vessels and see how blood moves through them. Duplex ultrasound helps diagnose venous or arterial thoracic outlet syndrome. 
• Electromyography (EMG) and nerve conduction study: Your doctor places electrodes on your skin over specific nerves. The test measures how well electrical signals travel through your nerves to muscles and how your muscles respond. It can help rule out cubital or carpal tunnel syndromes, which can have symptoms similar to neurogenic TOS. 
• Anterior Scalene Muscle block: Your doctor injects a medication into the muscles in your neck to help them relax. If the medication relieves symptoms, you likely have neurogenic TOS. 
• MRI: An MRI uses magnetic and radio waves to get a picture of your muscles and tissues. You may get a neck MRI to rule out a compressed spinal disc, which can cause symptoms similar to neurogenic thoracic outlet syndrome.

Thoracic Outlet Syndrome Treatment 

Your treatment plan depends on what type of thoracic outlet syndrome you have. Generally, the goal is to relieve symptoms and prevent complications. 

Neurogenic thoracic outlet syndrome treatment 

Treatment options for nerve-related TOS may include: 

• Physical therapy: You usually start treatment with physical therapy. A physical therapist teaches you exercises that help stretch and strengthen your shoulder. These movements can help to open your thoracic outlet and relieve the pressure on your nerves. 
• Botulinum toxin injections: Botulinum toxin injections may help relax tight neck muscles and temporarily relieve pain.
• Surgery: If noninvasive treatments don’t relieve symptoms, your vascular surgeon may recommend surgery. They may offer a scalenectomy, where they remove the muscles compressing the nerves in your thoracic outlet. Or they may perform a first rib resection. During this procedure, your vascular surgeon removes your first rib and some of the scalene muscle, the group of muscles between your neck and chest. Some people may also have an operation to divide the muscle in the upper chest (pectoralis minor), which can further relieve compression.

Venous thoracic outlet syndrome treatment 

Treatment options for vein-related TOS may include: 

• Medications: Your doctor may prescribe clot-dissolving or blood-thinning medications.
• Clot-removal procedures: Your vascular surgeon may perform a procedure to remove a blood clot using open or minimally invasive (endovascular) techniques. They may also recommend a balloon vein angioplasty (venoplasty) to restore blood flow. They use a thin, flexible tube (catheter) and a balloon to open your vein and improve circulation. 
• Surgery: Many people with venous thoracic outlet syndrome benefit from a first rib resection to relieve compression. 

Arterial thoracic outlet syndrome treatment 

Arterial TOS requires emergency surgery to restore blood flow and prevent limb loss. Your vascular surgeon may use an open approach or a minimally invasive procedure, such as catheter aspiration to remove clots, and place a wire reinforced tube (covered stent) that keeps the artery open. In some cases, they may use a piece of a blood vessel from elsewhere in your body (graft) to replace the damaged artery.

Additional treatments for arterial TOS may include: 

• Medications: You may take medicines to dissolve or prevent clots. 
• Surgery: People with arterial TOS may also benefit from a first rib resection to treat compression. 

Meet Our Team

UCLA Health leads one of the country’s highest-volume centers for thoracic outlet syndrome. We have pioneered minimally invasive treatments and continue to research and advance the field. You receive care from physician-scientists who study best practices and provide the latest treatment options.