What is Neurogenic Thoracic Outlet Syndrome

Neurogenic thoracic outlet syndrome (TOS) is a condition that happens when the nerves that supply your arm and hand (brachial plexus nerves) are squeezed (compressed).

To reach your arm, these nerves have to pass through a tight space under your collarbone (clavicle) and above your top rib (thoracic outlet). This is the most common type of TOS.

Depending on which structures are affected, you may have symptoms on one or both sides of your body.

What are the causes?

This condition may be caused by swelling or scarring in your neck muscles. The swelling and scarring result in the narrowing of your thoracic outlet. This leads to nerve compression. It can happen as a result of:

• Neck injuries from a motor vehicle collision (whiplash).
• Falls.
• Repetitive stress on your neck from working with your arms, especially if the arms are elevated. This stress could be from typing on a keyboard all day or working on an assembly line.
• Other forms of neck, shoulder, or arm injury.

What increases the risk?

The following factors may make you more likely to develop this condition:

• A neck injury.
• Repetitive stress on your neck.
• Being female.
• Being overweight.
• Having poor posture.

What are the signs or symptoms?

Symptoms of this condition include:

• Pain in your arm when at rest.
• Feeling numbness or tingling in your hand.
• Decreased strength in your arm.
• Muscle loss in the hands (rare).

All signs and symptoms of TOS may get worse when you hold your arms over your head.

How is this diagnosed?

Your health care provider may suspect TOS from your symptoms. A physical exam will be done. During the exam, your health care provider may ask you to hold your arms over your head and in other positions to check whether your symptoms get worse. Tests may also be done to confirm the diagnosis and to find out what is causing TOS. These tests may include:

• Imaging studies, such as:
  • X-rays to look for an extra rib at the base of your neck (cervical rib) or other abnormality of the ribs.
  • A test that uses sound waves to create an image (ultrasound).
  • CT scan.
  • MRI.
  • Venogram or angiogram. In these tests, X-rays are done after a dye is injected into an artery or vein.
• A test that involves measuring and recording the pulses in your wrists (pulse volume recording).
• A test that involves measuring the conduction speed of nerve impulses in your arm (nerve conduction test).

How is this treated?

This condition may be treated with:

• Physical therapy to learn stretching exercises and good posture.
• Occupational therapy to improve how your workplace and home are set up.
• Medicine, including pain medicine, muscle relaxants, and anti-inflammatory medicine.
• Surgery to remove scarred neck muscles or the first rib. This is rare.

Follow these instructions at home:

• Take over-the-counter and prescription medicines only as told by your health care provider.
• Maintain a healthy weight. Lose weight as told by your health care provider.
• Do stretching exercises as told by your health care provider or physical therapist.
• Maintain good posture.
• Do not carry heavy bags over your shoulder or repetitively lift heavy objects over your head.
• Take frequent breaks to stretch and rest your arms if you work at a keyboard or do other repetitive work with your hands and arms.
• Keep all follow-up visits as told by your health care provider. This is important.

Contact a health care provider if:

• You have pain, cramps, numbness, or tingling in your arm or hand.
• Your arm or hand often feels tired.
• Your arm turns into a darker and different skin color than usual.
• Your hand feels cold.
• You have frequent headaches or neck pain.
• You have muscle loss in your hand.

Get help right away if:

• You lose feeling in your arm or hand.
• You cannot move your fingers.
• Your fingers turn into a dark color.

Summary

• Neurogenic TOS happens when the nerves that supply your arm and hand are compressed.
• Neurogenic TOS may be caused by swelling or scarring in your neck muscles. These result in the narrowing of your thoracic outlet, leading to nerve compression.
• Signs and symptoms of this condition include pain in your arm when at rest, numbness or tingling in your hand, decreased strength in your arm, and muscle loss in your hands.
• This condition may be treated with physical therapy, occupational therapy, medicine, or surgery.