What is Thoracic Outlet Syndrome?

Thoracic outlet syndrome, or TOS, is a condition that includes a group of symptoms. Among these are shoulder pain, arm pain, arm and hand weakness, and tingling or numbness in the hands and fingers. TOS is often misdiagnosed as carpal tunnel syndrome because of the tingling in the fingers. However, TOS usually involves the little and ring fingers, whereas, carpal tunnel syndrome usually involves the thumb, index, and ring fingers. There is much controversy as to whether or not TOS even exists. In actuality, it is a combination of several conditions (which is why it is termed a “syndrome”). Most prominent among these is impingement of the brachial plexus (the nerves coming out of the neck and going to the arm) and/or the blood vessels that travel with it, and muscle tension in scalene muscles (the muscles in front of the neck) and in the shoulder area.

What is the thoracic outlet and why does it cause pain?

The thoracic outlet is a small area where the neck joins the shoulder. In this area, many nerves and blood vessels, together known as a neurovascular bundle, pass between the first rib and muscles called the scalene muscles. Normally, this opening is large enough for the neurovascular bundle to pass through without harm. However, several things can happen to cause this outlet to close down and put pressure on the bundle.

The first, and perhaps most common, is hunching of the back. When a person hunches the back, especially at a computer or at a job with repetitive types of motion, it forces the nerves and vessels to travel through a smaller opening. This is because slouching shortens the muscles in the front of the neck, thereby, decreasing the size of the outlet from top to bottom. The second thing that can cause a smaller space in the thoracic outlet is related to the first, but can also occur by itself. This is muscle spasm of the scalene muscles. As stated before, the scalenes are the muscles in the front of the neck. These muscles act as a guide wire for the head. They are long narrow muscles that connect to the upper ribs by passing under the collar bone. They are also involved in breathing. If these muscles are tense or tight, it will shorten the outlet and put pressure on the neurovascular bundle. One can generally tell if the scalene muscles are tense by putting gentle pressure just above the collar bone (only one side at a time). If this area is tender an painful, chances are that the scalene muscles are in spasm.

The third possible reason for TOS occurs f the first rib is slightly out of place. Since the first rib is the lower border of the thoracic outlet, when the rib is out of place, the dimensions of the outlet change. Another possibility is the presence of an extra rib in the neck. Normally, there are 12 pairs of ribs. They are connected to the twelve vertebrae known as the “thoracic vertebrae”. Together with these vertebrae, the ribs make up the “thoracic cage” or the chest wall. The cervical (neck), and lumbar (low back) vertebrae usually have no ribs attached to them. However, many people have one or two “extra” ribs that generally form in the base of the neck. These are referred to as “cervical ribs”. These ribs can affect and cause TOS because when they are present, they usually form in the area between the scalene muscles and the first rib; the exact area where the neurovascular bundle is supposed to pass through. However, it has been shown that not everyone who has cervical ribs develops TOS. This is most likely because our bodies accommodate for instances like these. It is clear, though, that those with cervical ribs are more likely to get the condition than someone who is “normal”. Other possible causes of TOS include, but are not limited to: longer bony protrusions than normal off of the cervical vertebrae; extra scalene muscles; extra ligaments; odd shaped first rib, or; scar tissue from a past injury or surgery.

What can I do about TOS if I already have it?

The single most important thing to do is determine the cause of the condition, and to rule out carpal tunnel syndrome. Chiropractors are perhaps the most adequately trained physicians in determining this. The diagnostic process may include muscle testing, nerve testing, and possibly x-rays. Once all the tests are done, and the chiropractor knows the cause, he will treat the condition. He will use electrical and ultrasound therapies, massage and muscle work, and most importantly, adjustments to the neck, upper back, and first rib. This will allow all the bones and muscles to move properly. The primary goal is to open the thoracic outlet and relieve the impingement on the neurovascular bundle.

How can I prevent TOS?

Sometimes you can’t. But for those who do not have a cervical rib, or an extra muscle, there is one word that is most important – posture! Avoid hunching your back. Also, try to stay stretched and avoid prolonged repetitive motions. By doing these, and other things the chiropractor will explain about your lifestyle, you can prevent or reduce the severity of TOS. Above all, and this cannot be stressed enough, at the first sign of any symptoms, get the condition checked out.

TOS is a condition that usually takes time to resolve and generally needs follow-up treatment every so often to avoid relapse. Once the thoracic outlet has been compromised, chances are it will be compromised again if left alone. TOS can also be rather serious if ignored; it can lead to nerve and muscle degeneration and partial to total loss of function in the affected hand and arm. Rarely, TOS can cause the same type of symptoms in both arms. Often, medical doctors will choose surgery as the only option. This approach is very rarely the best choice. With proper education and conservative treatment, TOS can be dealt with, without costing a fortune or requiring surgery. Click Here to go back to Conditions Menu