Thoracic Outlet Syndrome (TOS)

What is it?

Thoracic outlet syndrome (TOS) is a painful condition affecting the nerves (known as the brachial plexus) and blood vessels that run from the base of the neck to the shoulder and arm through a narrow passageway known as the thoracic outlet. Symptoms result from compression or narrowing of these neurovascular structures due to pressure from other structures, such as scar tissue, thickened neck musculature or an extra rib (known as cervical rib). This condition is often seen in overhead athletes, individuals with poor posture, body builders and people who do work involving repetitive overhead activity, though it can occur in anyone.

What symptoms does it cause?

Patients with TOS typically experience pain in the neck and shoulder often radiating into the arm and hand (usually the last two fingers). The pain can be described as achy or burning and is often associated with numbness and tingling. Sometimes, the affected arm will swell when elevated. Symptoms are generally worse with activity and when the arm is lifted overhead.

How is it diagnosed?

TOS is difficult to diagnose and requires a physician who is experienced in making the diagnosis. Though sophisticated nerve studies often cannot reliably diagnose TOS, they may be used to rule other neurologic problems and can help with making the correct diagnosis. Imaging studies, such as X-ray or MRI, may be used to evaluate the neck, shoulder and neurovascular structures. In rare cases, if a blood clot is suspected, special tests can be done to examine the blood vessels.

How is it treated?

Treatment is customized for each individual. Many patients will experience relief of symptoms with a sufficient course of physical therapy. An important part of treatment is avoiding activities that aggravate it. In severe cases, medications may be needed to control the symptoms. When the condition is more severe or abnormal structures are present, surgery may be considered.

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