Thoracic Outlet Syndrome

Thoracic outlet syndrome (TOS) is a syndrome involving compression at the superior thoracic outlet involving compression of a neurovascular bundle passing between the anterior scalene and middle scalene. It can affect the brachial plexus (nerves that pass into the arms from the neck), and/or the subclavian artery or vein (blood vessels that pass between the chest and upper extremity).

The compression may be positional (caused by movement of the clavicle (collarbone) and shoulder girdle on arm movement) or static (caused by abnormalities or enlargement of the various muscles surrounding the arteries, veins, and brachial plexus).

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TOS affects mainly the upper limbs, especially the arms and hands. Pain in the arms and hands is almost always present. Pain can be sharp, burning, or aching. Pain can involve only part of the hand, as in the 4th and 5th finger only, or all of the hand. It can involve the inner aspect of the forearm and upper arm. Pain can also be in the side of the neck, the pectoral area below the clavicle, the axillary area, and the upper back, as in the trapezius and rhomboid area. Decoloration of the hands is also a possible symptom, and one hand colder than the other hand is also common. Weakness of the hand and arm muscles is also common. Tingling can also be present.

Cerebrovascular arterial insufficiency when they affect the subclavian artery. It also can affect the vertebral artery, case in which it could produce transient blindness, and embolic cerebral infarction. A painful, swollen and blue arm, usually occurring after strenuous physical activity, could be a sign of a venous compression or subclavian vein thrombosis, called Paget-Schroetter Syndrome.

Adson's sign and the costoclavicular maneuver are notoriously inaccurate, and may be a small part of a comprehensive history and physical examination of a patient with TOS. There is currently no single clinical sign that makes the diagnosis of TOS with certainty. Doppler Arteriography, is very helpful to evaluate thoracic outlet syndrome, and may be used if a surgery is being planned to correct an arterial TOS. Additional maneuvers that may be abnormal are the "hand raise" for up to 3-5 minutes (holding both hands over head, the affected hand will often be paler than the unaffected because of compromised blood supply) and the "compression test" (pressure between the clavicle and medial humeral head causes radiation of pain / numbness into the affected arm).

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Continued and active postural changes along with osteopathic or chiropractic care, acupuncture, physiotherapy or massage therapy may suffice. The recovery process however is long term, and a few days of poor posture can often set one back.

About 10 to 15% of patients undergo surgical decompression following an appropriate trial of conservative therapy, most often specific physical therapy directed towards the treatment of thoracic outlet syndrome, and usually lasting between 6 and 12 months. Surgical treatment may include removal of anomalous muscles, removal of the native anterior and/or middle scalene muscles, removal of the first rib or, if present, a cervical rib, or neurolysis (removal of fibrous tissue from the brachial plexus). Surgical treatment for Thoracic Outlet Syndrome does have serious life long risk. A good number of individuals suffer moderate to severe post operative complications and worsening or returning of symptoms post first rib resection. This unfortunate portion of this patient population is often left out of most articles and abandoned by the TOS medical community.


The goal of self stretching is to relieve compression in the thoracic cavity, reduce blood vessel and nerve impingement, and realign the bones, muscles, ligaments, and tendons causing the problem.

  • Moving shoulders forward (hunching) then back to neutral, followed by extending them back (arching) then back to neutral, followed by lifting shoulders then back to neutral.
  • Tilting and extending neck opposite to the side of injury while keeping the injured arm down or wrapped around the back.

Nerve Gliding
This syndrome causes a compression of a large cluster of nerves, resulting in the impairment of nerves throughout the arm. By performing nerve gliding exercises one can stretch and mobilize the nerve fibers. Chronic and intermittent nerve compression has been studied in animal models, and has a well-described pathophysiology, as described by Susan Mackinnon, MD, currently at Washington University in St. Louis. Nerve gliding exercises have been studied by several authorities, including David Butler in Australia.

Extend your injured arm with fingers directly outwards to the side. Tilt your head to the other side, and/or turn your head to the other side. A gentle pulling feeling is generally felt throughout the injured side. Initially, only do this and repeat. Once this exercise has been mastered and no extreme pain is felt, begin stretching your fingers back. Repeat with different variations, tilting your hand up, backwards, or downwards.

TOS is rapidly aggravated by poor posture. Active breathing exercises and ergonomic desk setup can both help maintain active posture. Often the muscles in the back become weak due to prolonged (years) hunching.

Ice can be used to decrease inflammation of sore or injured muscles. Heat can also aid in relieving sore muscles by improving circulation to them. While the whole arm generally feels painful, some relief can be seen when ice/heat is applied to the thoracic region (collar bone, armpit, or shoulder blades).

Treatment is based upon the premise that nerve impingements can be caused by dysfunctional or malaligned vertebral segments, or by structures such as a tight pectoralis minor, scalenus anticus or cervical rib. By adjusting vertebral segments, the cervical rib and/or performing soft tissue therapies to the tight musculature, can help relieve the nerve impingement.

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Injected into a joint or muscle, cortisone can help relief and lower inflammation.

Botox injections
Short for Botulinum Toxin A, Botox binds nerve endings and prevents the release of neurotransmitters that activate muscles. A small amount of Botox injected into the tight or spastic muscles (usually one or all three scalenes) found in TOS sufferers often provides months of relief while the muscle is temporarily paralyzed. This noncosmetic treatment is unfortunately not covered by most medical plans and costs upwards of $400. The relief of symptoms from a Botox injection generally lasts 3-4 months, at which point the Botox toxin is degraded by the affected muscles. Serious side effects have been reported, and are similarly long-lasting, so improved understanding of the mechanism of a 'scalene block' is vital to determining the benefit and risk of using Botox. Additionally, many patients report ZERO relief from Botox or scalene injections with associated post injection flare noted.

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Surgical approaches have also been used. In cases where the first rib is compressing a vein, artery, or the nerve bundle, the first rib and scalene muscles and compressive fibrous tissue can be removed. The procedure is called a first rib resection and scalenectomy and involves going through the underarm area or anterior scalene neck area and removing the first rib, scalene muscles, and any compressive fibrous tissue to open the area to allow blood flow and reduce nerve compression. Physical therapy is used both before the operation and after to further the patient's success in recovery. Complications include pneumothorax, infection, loss of feeling, pain, and as in all surgeries, a very small risk of death and a very LARGE risk of permanent life long injury.

Some physicians advocate the injection of a short-acting anesthetic such as xylocaine or marcaine into the anterior scalene, subclavius, or pectoralis minor muscles as a provocative test to assist in the diagnosis of thoracic outlet syndrome. This is referred to as a 'scalene block'. However, this is not considered a 'treatment', as the relief is expected to wear off within an hour or two, at a maximum. Active research continues into the accuracy and risks of this provocative test. It is noted that this above "active research" is NOT referring to any nationally proven NIH collaborative research in the United States. As with the current Canadian Botox trial, study subjects have NOT been proven to have Thoracic Outlet Syndrome with any proven diagnostic testing whatsoever, therefore making the Canadian Botox trial invalid.

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Babu, Sateesh C., MD
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Arun Goyal, MD
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Igor Laskowski, MD
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