Thoracic Outlet Syndrome
What is Thoracic Outlet Syndrome?
Thoracic outlet syndrome is a complex disorder characterized by a constellation of signs and symptoms resulting from the compression of blood vessels and nerves (neurovascular bundle) in the thoracic outlet region where they exit the chest. The thoracic outlet is a space located between the thorax (rib cage) and the clavicle (collar bone) which contains major blood vessels (subclavian artery and vein) and nerves (brachial plexus). The thoracic outlet is the area through which nerves and blood vessels travel to and from the arm.
Thoracic outlet syndrome is considered a “syndrome” since it involves multiple systems, including:
- Neural (nerve) complexes
- Vascular structures
- Musculoskeletal system
The nerves that travel through the thoracic outlet originate at the level of the cervical and/or thoracic spine (C5-C8 and T1). These nerves are bundled together into the brachial plexus. The brachial plexus passes through a notch in the bone at the base of the neck and then passes under the scalene muscles and continues under the collarbone and across the front of the shoulders. In the area of the axilla (arm pit) the brachial plexus divides into the three major nerves of the arm, ulnar, median, and radial nerves. Thoracic outlet syndrome involves the brachial plexus before it divides and typically affects the ulnar and radial nerves.
The blood vessels that travel through the thoracic outlet include:
- Subclavian artery which supplies oxygenated blood to the arm from the aorta
- Subclavian vein which returns the deoxygenated blood from the arm to the heart
The bones and muscles form the backdrop for proper passage and support for the nerves and blood vessels that traverse the upper body. The components involved in this process include:
Proper bone alignment – the neck vertebrae, first rib and collarbone must be aligned properly to allow enough space for the brachial plexus and subclavian blood vessels to pass through the correct path without obstruction or interference.
Proper muscle alignment – muscles of the upper body must be aligned in proper form, particularly the scalene muscles. The scalene muscles consist of three powerful muscles on each side of the neck that bend and rotate the neck, and assist in breathing by raising the first two ribs during inspiration (breathing in). The ideal posture which promotes the most appropriate muscle alignment is when the head sits directly atop the shoulders which we identify as erect posture.
Anatomy of the Thoracic Outlet
There are actually three spaces where compression can occur causing the symptoms of thoracic outlet syndrome, including:
- The thoracic outlet (also called the scalene triangle) – is located at the base of the neck above the first rib and behind the clavicle. This space lies closest to the neck. The boundaries of the thoracic outlet consist of:
- anterior scalene muscle which forms the front of the thoracic outlet
- middle scalene muscle which forms the back of the thoracic outlet
- first rib which forms the bottom of the thoracic outlet.
The subclavian artery and the brachial plexus are located between the first rib and the scalene muscle while the subclavian vein sits outside the scalene muscle.
- Costoclavicular space – this space is located adjacent to the scalene triangle and lies between the following structures:
- first rib
- costoclavicular ligament
- edge of the middle scalene muscle
The subclavian artery, vein, and brachial plexus all pass through the costoclavicular space.
- Subcoracoid space which lies adjacent to the costoclavicular space and is closest to the arm. The location of this space is:
- under the pectoralis muscle
- under the coracoid process
- in front of the ribs
If there are any anomalous bony structures (e.g., cervical rib) touching upon these small spaces, they have the potential to compress the neurovascular structures which pass through them. Approximately 0.17 to 0.74% of the general population has an anomalous rib and only 10% of people with such a cervical rib actually develop thoracic outlet syndrome. Thoracic outlet syndrome typically occurs following trauma to the cervical spine.
Because thoracic outlet syndrome is thought by some experts to be underdiagnosed and in some cases misdiagnosed, it is difficult to estimate with any degree of accuracy how many people suffer from this condition. The incidence of thoracic outlet syndrome in the U.S. population has been broadly estimated to range from 0.3% to 8%. The most common age range is 25 to 40 years and women are affected about 4 times more frequently than men.
Knowledge is Critical when Dealing with a Life-Altering Condition such as Thoracic Outlet Syndrome
If you or a loved one has been diagnosed with thoracic outlet syndrome, it’s critical to learn everything you possibly can about this condition so that you can make informed decisions about your treatment. That’s why we created the Medifocus Guidebook on Thoracic Outlet Syndrome, a comprehensive 101 page patient Guidebook that contains vital information about thoracic outlet syndrome that you won’t find anywhere in a single source.
The Medifocus Guidebook on Thoracic Outlet Syndrome starts out with a detailed overview of the condition and quickly imparts fundamentally important information about thoracic outlet syndrome, including:
- The theories regarding the underlying causes of thoracic outlet syndrome.
- The risk factors that can increase a person’s chances for developing thoracic outlet syndrome.
- A detailed overview of the three major types of thoracic outlet syndrome, which include:
- Neurogenic thoracic outlet syndrome
- Vascular thoracic outlet syndrome
- Neurovascular thoracic outlet syndrome
- The signs and symptoms of thoracic outlet syndrome.
- How thoracic outlet syndrome is diagnosed based on factors such as signs/symptoms, patient history, physical examination, provocative compression maneuvers, and imaging studies. *Other underlying medical conditions that may be confused with thoracic outlet syndrome and must be considered in the differential diagnosis of thoracic outlet syndrome.
Understanding the Standard Treatments… and the Treatment Options
- The goals of treatment for patients with thoracic outlet syndrome include:
- Relieving compression of the nerves and/or blood vessels in the thoracic outlet region.
- Controlling and minimizing pain and other symptoms associated with thoracic outlet syndrome.
- Enabling patients to continue to function and lead a reasonably good quality of life.
- Understanding the standard treatments – and the treatment options – is critical for successfully achieving the goals of treatment for thoracic outlet syndrome. As you read through the section of the Guidebook that focuses on the treatments for thoracic outlet syndrome, you will specifically learn about:
- The role of conservative treatments as the first-line approach for the treatment of thoracic outlet syndrome, including:
- Physical therapy
- Ultrasound therapy
- Transcutaneous electrical nerve stimulation (TENS)o Postural training
- The medications that may be prescribed to control pain in patients with thoracic outlet syndrome, including:
- Muscle relaxants
- Nerve blocks
- The surgical treatment options that are currently available for the management of thoracic outlet syndrome, which include:
- Transaxillary first rib resection
- Cervical scalenectomy
- Resection of fibrous bands
- The treatment options that are currently available for the management of vascular thoracic outlet syndrome.
- The role of lifestyle modifications in helping patients to better control the symptoms of thoracic outlet syndrome.
- Quality of life issues that often confront people with thoracic outlet syndrome and how to minimize their impact and cope better with these issues.
- Important questions to ask your doctor about thoracic outlet syndrome.
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