Thoracic Outlet Syndrome

Definition

Thoracic outlet syndrome occurs when the blood vessels and nerves under the collarbone traveling to the arm are compressed between the collarbone and the first rib. The thoracic outlet is between the collarbone and rib cage. Patients with thoracic outlet syndrome often have it as a result of the anatomy they're born with, though symptoms may not appear for decades.

Causes

• Trauma to the shoulder or collarbone area
• An extra rib above the first rib
• Abnormally tight fibrous band (ligament) connecting the spinal vertebra with the ribs
  

Risk

• Repetitive motion with the arms extended over the head
• Long, muscular neck
• Droopy shoulders or poor posture
• Having either a long neck or droopy shoulders puts extra pressure on the nerves and blood vessels near the collarbone.
  

Symptoms

• Pain, numbness and tingling in the last three fingers and inner forearm
• Weakness and fatigue in the forearm and hand muscles, particularly when doing something with the arms over the head, such as washing hair
• Pain and tingling in the neck and shoulders, which may worsen if you carry something heavy or work with the arms extended over the head
• Arm turns pale when lifted
  

Diagnosis

• X-ray: An X-ray may find an extra rib causing thoracic outlet syndrome, or may find evidence of an old rib or collarbone fracture.

• Upper extremity blood pressure evaluation: Blood pressure cuffs and ultrasound are used to measure and evaluate the blood flow and blood pressure in both arms to see if blood flow is being restricted by compression of the artery under the collarbone. Ultrasound can also be used to look for narrowing of the artery or blood clots in the vein under the collarbone that may result from compression of the artery and vein.
• Magnetic Resonance Imaging (MRI): Radio waves and magnetic fields may show an abnormally tight fibrous band causing the syndrome.
• Nerve conduction velocity study: Nerve damage around the collarbone is determined by the speed of nerve signals moving through the body. Patches that give off an electrical impulse (surface electrodes) are placed at various points in the area of the collarbone to measure nerve signal speed.
• Electromyography: An electrode is inserted into a muscle near the collarbone to determine the health of the muscle and the nerves controlling that muscle by measuring electrical activity.

Treatment

• Physical therapy: A physical therapy program may strengthen the shoulder muscles and improve the posture, relieving the symptoms.
• Surgery: Surgery may be indicated to alleviate the pressure and compression of the artery or nerves. Removal of the first rib and the constricting bands and muscles usually alleviates the problem by decompressing the artery and nerves. If the problem is a result of a previous fracture of the collarbone, removal of the collarbone may be needed. Occasionally, a bypass may be required to reconstruct the artery if it has been compressed for a long time and is permanently injured.