Thoracic outlet syndrome:
is actually a collection of syndromes brought about by abnormal compression of the neurovascular bundle by bony, ligament or muscular obstacles between the cervical spine and the lower border of the axilla (armpit).
What does that mean?
First of all a syndrome is defined as a group of signs and symptoms that collectively characterizes or indicates a particular disease or abnormal condition.
- The neurovascular bundle which can suffer compression consists of the brachial plexus plus the C8 and Tl nerve roots and the subclavian artery and vein.
- The brachial plexus is the network of motor and sensory nerves which innervate the arm, the hand, and the region of the shoulder girdle.
- The vascular component of the bundle, the subclavian artery and vein transport blood to and from the arm, the hand, the shoulder girdle and the regions of the neck and head.
The bony, ligamentous, and muscular obstacles all define the cervicoaxillary canal or the thoracic outlet and its course from the base of the neck to the axilla or arm pit. Look at the scheme of this region and it all becomes more easily understood.
What are the signs and symptoms of thoracic outlet syndrome?
Vascular symptoms include:
Neurologic symptoms include:
What causes the neurovascular compression?
Compression occurs when the size and shape of the thoracic outlet is altered. The outlet can be altered by exercise, trauma, pregnancy, a congenital anomaly, an exostosis, postural weakness or changes.
Below is a list of the component syndromes which comprise thoracic outlet syndrome along with a brief description of each. Refer to the scheme for questions about the anatomy of the region.
Anterior scalene tightness
Compression of the interscalene space between the anterior and middle scalene muscles-probably from nerve root irritation, spondylosis or facet joint inflammation leading to muscle spasm.
Compression in the space between the clavicle, the first rib and the muscular and ligamentous structures in the area-probably from postural deficiencies or carrying heavy objects.
Pectoralis minor tightness
Compression beneath the tendon of the pectoralis minor under the coracoid process-may result from repetitive movements of the arms above the head (shoulder elevation and hyperabduction).
What activities can cause Thoracic outlet syndrome?
Thoracic outlet syndrome has been described as occurring in a diverse population. It is most often the result of poor or strenuous posture but can also result from trauma or constant muscle tension in the shoulder girdle.
Static postures such as those sustained by assembly line workers, cash register operators, students of, for example, those who do needle work often result in a drooping shoulder and forward head posture. This position of the shoulders and head is also indicative of poor upper body posture. Middle aged and elderly women who suffer from osteoporosis often display this type of posture as a result of increased thoracic spinal kyphosis.
Carrying heavy loads, briefcases and shoulder bags can also lead to thoracic outlet syndrome. Humans are not well adapted as beasts of burden and heavy loads hung form the shoulders and arms can stress the supporting structures of the shoulder girdle which is basically suspended by the clavicle and all of the component ligaments and muscles.
Occupations which require repetitive over head arm movements can also produce symptoms of thoracic outlet syndrome . Electricians, painters and plasterers may develop hyperabduction syndrome. Compression of the neurovascular structures also occurs in athletes who repetitively hyperabduct their arms. Swimmers, volleyball players, tennis players and baseball pitchers may suffer compression of the neurovascular structures as well. However, compression of these structures may be caused by stretching or microtrauma (small tears in muscle tissue) to the muscles which support the scapula.
How is thoracic outlet syndrome treated?
The first step to beginning any treatment begins with a trip to the doctor. Make a list of all of the symptoms which seem to be present even if the sensations are vague. Make a note of what activities and positions produce or alleviate the symptoms and the time of day when symptoms are worst. Also, note when the symptoms first appeared. This list is important and should also include any questions one may have.
Due to overlapping in terms of symptoms it’s difficult to make a definitive diagnosis; this is why a list is so important. Certain diagnostic tests have been designed which are very useful for examination. These tests involve maneuvers of the arms and head and can help the practitioner by providing information as to the cause of the symptoms and help in designing an approach to treatment. These tests, accompanied by a thorough history help in ruling out other causes which may produce similar symptoms. These include Pancoast tumor, neurofibromas, cervical spondylosis, cervical disk herniation, carpal tunnel syndrome and cubital tunnel syndrome. Don’t forget to ask your practitioner about these conditions as well.
Once a diagnosis is decided, every effort is made for a conservative treatment approach. That means it won’t hurt. Should symptoms persist over 3 or 4 months or if there is intractable pain, vascular loss or neuralgic loss then surgery should be considered. Surgery is consistent in relieving pain but muscle weakness and atrophy do not usually improve significantly.
Conservative treatment usually includes local heat and a program which address postural retraining, shoulder strengthening and stretching exercises. The practitioner will create a treatment program specific to the presenting symptoms.