Symptoms of thoracic outlet syndrome may include:

• Pain, numbness, and tingling in the last three fingers and inner forearm
• Pain and tingling in the neck and shoulders (carrying something heavy may make the pain worse)
• Signs of poor circulation in the hand or forearm
• Weakness of the muscles in the hand

When you lift something, the arm may appear pale due to pressure on the blood vessels. Rarely, the arm may be smaller on the side of the symptoms. This is often present since birth (a congenital anomaly).

The diagnosis is typically made after the doctor takes a careful history and performs a physical examination. Sometimes tests are done to confirm the diagnosis, including the following:

• Electromyography (EMG)
• MRI
• Nerve conduction velocity study
• X-ray

Tests should also be performed to make sure there are no other problems, such as carpal tunnel syndrome or a damaged nerve due to problems in the cervical (neck) spine.