Thoracic Outlet Syndrome

Diagnosis

To diagnose thoracic outlet syndrome, your doctor asks you questions about your symptoms, occupation and medical history. Your doctor also performs a physical exam to evaluate your nerve and muscle function and blood flow and to look for swelling and discoloration. Range-of-motion tests help your doctor determine if changes in position affect compression of the nerves and blood vessels.

Your doctor may order several diagnostic tests to rule out other conditions and confirm the diagnosis of thoracic outlet syndrome, including:

• X-ray. An X-ray can reveal a small extra rib (cervical rib), which may be the cause of nerve or blood vessel compression.
• Ultrasound. An ultrasound helps your doctor examine blood flow while you do range of motion maneuvers with your arm.
• Venogram. In a venogram, your doctor injects a dye into your blood vessels, then takes an X-ray to examine blood flow and check for blood clots.
• Electromyography (EMG). An EMG evaluates the function of your nerves and muscles. Your doctor applies electrical shocks to the skin to evaluate your nerve function. A small needle inserted in your muscles will help your doctor evaluate your muscles' electrical activity. This test helps determine if your nerves and muscles show abnormalities that occur with thoracic outlet syndrome.
• Magnetic resonance imaging (MRI). During an MRI, magnetic fields are used to create images of your soft tissues and help your doctor find the location of the compression.

Read more about X-ray, ultrasound and MRI at www.MayoClinic.com.