Thoracic outlet syndrome refers to a group of conditions characterized by the compression of the nerves, arteries, and veins that pass through the space between the collarbone and the first rib. This space is known as the thoracic outlet.

Anything that narrows the space inside the thoracic outlet can put pressure on the blood vessels and nerves. This can cause pain in the neck, shoulders, and arms.

Thoracic outlet syndrome can develop if a person has poor posture, if they injure their shoulder, or if they perform repetitive shoulder and arm movements.

People tend to develop symptoms of thoracic outlet syndrome in their early adulthood, according to the authors of one 2018 article.

Treatments for thoracic outlet syndrome include physical therapy, medication, and surgery to increase the size of the thoracic outlet and relieve pressure from the blood vessels and nerves.

Read on to learn more about thoracic outlet syndrome, its symptoms, and how doctors may diagnose and treat it. This article also provides some shoulder-strengthening exercises that may help reduce the symptoms of thoracic outlet syndrome.

The symptoms of this condition vary depending on the type of thoracic outlet syndrome a person has. The sections below discuss the symptoms of thoracic outlet syndrome by type.

Neurogenic thoracic outlet syndrome

a woman holding her shoulder because she has thoracic outlet syndromeShare on Pinterest
A person with neurogenic thoracic outlet syndrome may experience pain in the neck or shoulder.

Neurogenic thoracic outlet syndrome is the most common form of the condition.

It affects groups of nerves that travel from the cervical spinal cord down the arm. These nerves form the brachial plexus.

This type of thoracic outlet syndrome has subtypes depending on whether the compression affects the upper or lower portions of the brachial plexus.

Some symptoms of neurogenic thoracic outlet syndrome include:

  • pain or a dull aching in the neck, shoulder, armpit, arm, or hand
  • weakness in the arm and shoulder
  • numbness or pins and needles in the fingers and hand
  • changes in the color and temperature of the hand
  • atrophy, or muscle wasting, in the hand

Venous thoracic outlet syndrome

Venous thoracic outlet syndrome involves the compression of the subclavian vein. This is a large blood vessel located deep within the neck.

This type of thoracic outlet syndrome often develops as a result of repetitive arm movements.

Symptoms associated with venous thoracic outlet syndrome include:

  • pallor or paleness in one arm
  • a weak pulse in the arm
  • pain, tingling, or swelling in the arm and hand
  • weakness or a loss of sensation in the arm and hand

Arterial thoracic outlet syndrome

This type of thoracic outlet syndrome occurs when a blood clot forms in the subclavian artery. These arteries supply blood to the head, neck, arms, and shoulders.

According to the National Organization for Rare Disorders, blood clots that compress the subclavian artery usually develop because a cervical rib causes changes in the artery. A cervical rib is an extra rib that forms above the first rib before birth.

Arterial thoracic outlet syndrome can cause the following symptoms:

  • blood clots
  • swelling or redness of the arm
  • hands or arms that feel cool to the touch
  • heaviness of the arm
  • numbness or loss of sensation in the arm or hand

Various factors can increase a person's risk of developing thoracic outlet syndrome. These can include:

  • working a job that requires repetitive arm, shoulder, and neck movements, such as assembly line work, hair styling, and certain sports activities
  • having poor posture
  • having a history of soft tissue injuries or trauma involving the neck
  • frequently lifting heavy loads
  • having a congenital abnormality in the neck, shoulder, or arm regions

The sections below will cover these possible causes in more detail.

Injuries

Injuries that involve the neck, such as whiplash, can cause inflammation and tears in the neck muscles. Scar tissue may form when the muscle heals, which can put pressure on the nerves that run down the arm.

Poor posture

Hunching over or carrying excess weight in the abdominal region can compress the space between the collar bone and the rib cage, leaving less space for the nerves and blood vessels.

Structural abnormalities

Having an extra rib above the first rib can affect the structure of the subclavian artery. Bony growths on the collar bone or first rib can press against the brachial plexus or subclavian blood vessels.

Repetitive movements

Repetitive arm and shoulder movements can irritate the brachial plexus nerves or cause swelling that constricts the space inside the thoracic outlet.

Thoracic outlet syndrome affects the nerves and blood vessels that run from the base of the neck to the armpits and arms.

According to the National Institute of Neurological Disorders and Stroke, healthcare professions may have difficulty diagnosing thoracic outlet syndrome because it causes symptoms that occur in many other conditions, including:

Doctors can use a variety of tests to help them diagnose the type and cause of thoracic outlet syndrome.

They will usually begin the diagnostic process by reviewing a person's medical history and performing a physical exam.

Doctors can diagnose venous and atrial thoracic outlet syndrome if a person presents physical symptoms such as a swollen or discolored arm.

According to the Genetic and Rare Diseases Information Center, 80–99% of people with thoracic outlet syndrome report paresthesia. This refers to an abnormal tingling or prickling sensation that occurs as a result of pressure on or damage to the peripheral nerves.

If a person has paresthesia or other symptoms that suggest nerve involvement, a doctor will likely test the nerves in the neck and arms. They can do this by asking a person to do things that put stress on these nerves, such as tilting the head back, rotating the neck, or bending and flexing the wrist.

A doctor may also perform a scalene muscle block test. This involves injecting a local anesthetic into the scalene muscles on either side of the neck. People with neurogenic thoracic outlet syndrome will usually experience an improvement in their symptoms after receiving this injection.

The doctor may decide to perform one or more of the following tests to confirm the diagnosis:

  • electromyography
  • nerve conduction velocity test
  • X-rays
  • MRI scan
  • ultrasound
  • arteriography or venography

Treatment options for thoracic outlet syndrome focus on reducing symptoms such as pain and numbness. The specific treatment a doctor recommends will depend on the type and underlying cause of the person's condition.

The sections below cover the treatment options for thoracic outlet syndrome in more detail.

Physical therapy

Physical therapy can help strengthen and increase flexibility in the shoulder and neck muscles. Doctors can recommend physical therapy for any type of thoracic outlet syndrome, but it may offer significant benefits for people with poor posture.

Combining resistance exercises and shoulder stretches will strengthen the shoulder and neck muscles, which can help expand the thoracic outlet and relieve pressure from the blood vessels and nerves.

Medication

Taking over-the-counter anti-inflammatory medications, such as ibuprofen or naproxen (Aleve), can help reduce swelling and relieve pain.

Doctors can also administer thrombolytic drugs to break up blood clots in a vein or artery. People who have thoracic outlet syndrome due to blood clots can take anticoagulants to prevent the formation of future clots.

Surgery

A person might require surgery if their symptoms do not improve with medication and physical therapy.

Surgery for thoracic outlet syndrome usually involves removing a section of the first rib and, in some cases, removing part of the scalene muscle.

A surgeon may need to perform vascular reconstruction to any damaged arteries or veins. Vascular reconstruction involves replacing a damaged blood vessel with a new vessel, called a graft. Surgeons can use synthetic grafts or tissue grafts, which contain either the person's own tissue or a donor's tissue.

Exercises

People with thoracic outlet syndrome can work with a physical therapist to build a personalized treatment plan that consists of the optimal exercises and stretches for their symptoms.

Examples of shoulder exercises that people can try to alleviate the symptoms of thoracic outlet syndrome include:

Arm raises

  • Stand upright with the feet hip-width apart and the arms relaxed.
  • Hold one small weight in either hand.
  • Contract the abdominal muscles and raise the arms until they are in line with the shoulders, creating a T-shape.
  • Slowly lower the arms back to the starting position.
  • Contract the abdominal muscles and raise the arms in front of the body until they are in line with the shoulders.

Standing shoulder pull

  • Find a cable machine and lower the cables to shoulder height.
  • Standing in front of the cable machine, take hold of the cables — one in each hand — and step backward until the arms are straight in front of the body and aligned with the shoulders.
  • Make sure the backs of the hands are facing the ceiling.
  • Slowly pull the cables toward the body by bending the elbows and drawing to the side of the rib cage.
  • Hold for 1 or 2 seconds and slowly release, returning to the starting position.

Scapular squeeze

  • Sit or stand with the arms by the sides and the back straight.
  • Squeeze the shoulder blades together and hold for 3–5 seconds.
  • Relax the shoulders.

People should see a doctor if they experience any symptoms of thoracic outlet syndrome that last for several days or weeks.

Those with a diagnosis of thoracic outlet syndrome may want to contact their doctor if they experience any new or worsening symptoms.

Thoracic outlet syndrome occurs when the blood vessels and nerves in the thoracic outlet become compressed. This can occur for numerous reasons.

For example, injuries such as whiplash can cause scarring in the neck muscles, which can put pressure on the structures inside the thoracic outlet.

Poor posture and repetitive shoulder and arm movements can irritate the muscles and nerves in the shoulder, which can lead to inflammation and increased pressure on the blood vessels and nerves.

The condition causes a variety of symptoms, depending on the affected structure. For example, compression of the nerves can cause muscle wasting and numbness and tingling in the arms, hands, and fingers.

Pressure on the blood vessels can result in blood clots or swelling and discoloration of the arm, hand, or fingers.

Doctors can treat thoracic outlet syndrome with physical therapy, medication, and, in severe cases, surgery.