Thoracic Outlet Syndrome

Alternative names: TOS

Thoracic outlet syndrome is an uncommon condition usually presenting with pain in the neck and shoulders, numbness and tingling in the inner forearm, pinky and ring fingers, and a weak grip.

Causes and Development

Common causes of thoracic outlet syndrome include:

• physical trauma (e.g. from a car accident)
• repetitive work- or sports-related injuries
• certain anatomical defects (such as an extra rib)
• pregnancy

In some cases the cause is unknown.

Signs and Symptoms

Symptoms may include:

• pain, numbness, and tingling in the pinky and ring fingers, and in the inner forearm
• pain and tingling in the neck and shoulders
• signs of poor circulation in the affected hand or forearm (bluish color, coldness, swelling)
• weakness in the hands
• arm pallor when lifting something

Diagnosis and Tests

Diagnosis involves first ruling out other conditions, such as carpal tunnel syndrome or nerve damage.  Electromyography (EMG), CT angiogram, MRI, nerve conduction velocity study, and X-ray may be used to narrow down the problem.

Treatment and Prevention

Treatment usually involves physical therapy, pain relief and improved posture.  Surgery may be required if physical therapy and behavioral changes do not improve symptoms: An extra rib may be removed, and certain muscles cut.