Your thoracic outlet is located at the junction of your shoulder and torso, it is the internal opening where the nerves and blood vessels enter your arm from your body. Thoracic Outlet Syndrome (TOS) is a condition where the thoracic outlet becomes constricted which creates pressure on the nerves and blood vessels that pass through it. This pressure creates localised pain in your neck, shoulder and upper back accompanied by pain, numbness, weakness and tingling in your arm and hand.
When TOS occurs 95% of the time it is the result of pressure on the nerves in the thoracic outlet rather than on the veins and arteries. The most common causes of TOS are trauma to the shoulder and neck, from poor postural habits and from sport and other activities that strain the neck.
In the case of trauma a broken collar bone might bend downwards at the fracture line creating pressure on the thoracic outlet. A whip-lashed neck, particularly from a side on impact can create inflammation and swelling that likewise pressurises the nerves, veins and arteries in your shoulder.
When TOS is caused by poor posture and repetitive strain the scalenes (muscles at the side of your neck) stiffen to the point where they start to occlude the thoracic outlet thus creating symptoms in your arm and hand.
Less commonly a minor deformity of the vertebrae (bone) in your neck might create TOS taking the form of a false short rib.
The symptoms and causes of TOS are similar in many ways to that of carpel tunnel syndrome (CTS), with the important distinction that CTS can be exclusively a problem of repetitive strain to the muscles of the forearm. CTS also affects the whole hand whereas TOS affects only the little finger side of your hand.
Sport and other physical activity that requires repetitive raising of your arms above your head can cause TOS, these activities include weight lifting, swimming, volleyball and working above your head as often experienced by plumbers and electricians. Avoidance of these activities lessen the likelihood of getting TOS.
Sitting for long periods infront of your computer screen can give you TOS, always remember that your body is made to move, that is why we have muscles and joints. Doing regular neck stretching exercises can go a long way to protect you from getting TOS.
TOS is described as being positional or static. If your symptoms only occur when you arm is held in a particular position your TOS is positional. If your TOS is constant it is static.
The most effective therapies for treating TOS include osteopathy, chiropractic, physiotherapy, acupuncture, massage and stretching. Avoiding activities that have caused the symptoms are obviously helpful too but if you cannot do this because it is part of your job you are best advised to get regular preventive treatment and exercise.
If your TOS is the result of a deformed vertebrae or depressed fracture of the collar bone you may require surgery.