Diagnosis

Diagnosing thoracic outlet syndrome can be difficult because the symptoms and their severity can vary greatly among people with the disorder. To diagnose thoracic outlet syndrome, your doctor may review your symptoms and medical history and conduct a physical examination.

• Physical examination. Your doctor will perform a physical examination to look for external signs of thoracic outlet syndrome, such as a depression in your shoulder, swelling or pale discoloration in your arm, abnormal pulses, or limited range of motion.
• Medical history. Your doctor will likely ask about your medical history and symptoms, as well as your occupation and physical activities.

Provocation tests

Provocation tests are designed to try to reproduce your symptoms. The tests may help your doctor determine the cause of your condition and help rule out other causes that may have similar symptoms.

In these tests, your doctor may ask you to move your arms, neck or shoulders in various positions. Your doctor will check your symptoms and examine you in different positions.

Imaging and nerve study tests

To confirm the diagnosis of thoracic outlet syndrome, your doctor may order one or more of the following tests:

• X-ray. Your doctor may order an X-ray of the affected area, which may reveal an extra rib (cervical rib). X-rays may also rule out other conditions that may be causing your symptoms.
• Ultrasound. An ultrasound uses sound waves to create images of your body. Doctors may use this test to see if you have vascular thoracic outlet syndrome or other vascular problems.
• Computerized tomography (CT) scan. A CT scan uses X-rays to obtain cross-sectional images of your body. A dye may be injected into a vein to view the blood vessels in greater detail (CT angiography). A CT scan may identify the location and cause of blood vessel (vascular) compression.
• Magnetic resonance imaging (MRI). An MRI uses powerful radio waves and magnets to create a detailed view of your body. Your doctor may use an MRI to determine the location and cause of blood vessel (vascular) compression. An MRI may reveal congenital anomalies, such as a fibrous band connecting your spine to your rib or a cervical rib, which may be the cause of your symptoms.
• Angiography. In some cases, you may be given an intravenous dye before a CT or MRI scan. The dye helps to make blood vessels more visible on the images.

• Arteriography and venography. In these tests, your doctor inserts a thin, flexible tube (catheter) through a small incision, usually in your groin. The catheter is moved through your major arteries in arteriography, or through your veins in venography, to the affected blood vessels. Then your doctor injects a dye through the catheter to show X-ray images of your arteries or veins.

  Doctors can check to see if you have a compressed vein or artery. If a vein or artery has a clot, doctors can deliver medications through the catheter to dissolve the clot.

• Electromyography (EMG). During an EMG, your doctor inserts a needle electrode through your skin into various muscles. The test evaluates the electrical activity of your muscles when they contract and when they're at rest.
• Nerve conduction study. These tests use a low amount of electrical current to test and measure your nerves' ability to send impulses to muscles in different areas of your body. This test can determine if you have nerve damage.