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The thoracic outlet is the space between the collarbone and the first rib. Through this space runs the nerve and blood vessel bundle that supplies the arm. Thoracic outlet syndrome is what happens when this bundle is compressed. Finally, you can do thoracic outlet syndrome exercises to relieve this condition.
People with thoracic outlet syndrome can experience pain running down their arm, numbness, tingling, and loss of function in the arm and hand. Because the vessel returning blood from the arm can be compressed, (and is lower pressure) this syndrome can also cause the arm to become swollen, though this isn’t as common.
Causes of thoracic outlet syndrome include:
This syndrome causes symptoms that are similar to other conditions, like angina (reduced blood flow to the heart) and cervical (neck) disc prolapse or protrusion. This is known as the differential diagnosis.
Generally, if you have thoracic outlet syndrome, the symptoms get worse when you raise your arms. This is because this motion decreases the space available for the nerves and vessels running between your collarbone and first rib.
Because the pain of TOS comes from squeezing a nerve, it tends to be a nerve-like pain in the distribution of the nerve. This means shooting, or stabbing intermittent electric or very sharp pain, which runs in a thin band down the arm. It will often have numbness and tingling associated with it, in the same distribution.
This is very hard to distinguish from pain caused by a disc protrusion, since the same nerves are being compressed. Pain from a prolapsed neck disc tends to get worse in particular neck positions. Often with a prolapsed disc you will have pain in the neck as well.
The pain of angina is of a different quality. It tends to be deep, diffuse, hard to localise. It also tends to get worse when you exercise, and is relieved with rest. You’ll also often have chest pain.
Clinically, you can discriminate between a prolapsed disc and thoracic outlet syndrome. In the next, there is a test called Spurling’s test, where you extend and rotate the neck towards the side which hurts.
Extend means leaning your neck back, and twisting toward the side of the pain. The examiner then puts a little bit of pressure on your head, which puts the disc in compression.
These maneuvers reduce the size of the foramen (the hole) which the nerve has to exit through in the neck. If there is a disc prolapse, this will set off your pain. A positive test provokes arm pain.
For thoracic outlet syndrome, the examiner will feel the radial pulse at your wrist. With the arm hanging down, you should be able to feel the pulse quite easily.
The examiner keeps their finger on your pulse and slowly lifts your arm above your head. If the thoracic outlet is tight, the pulse will diminish or disappear completely. This proves there is compression of the thoracic outlet. The examiner should be able to find trigger points in the pectoralis minor and the scalenes.
The definitive investigation would be to do an MRI of the neck, where you can clearly see if there’s a prolapsed disc or not. There isn’t really a scan-type investigation of the thoracic outlet. To rule out angina, you can have an exercise ECG, or a cardiac angiogram.
There are two primary muscles that can relieve thoracic outlet syndrome: the pectoralis minor, and the scalenes. The scalenes are neck muscles, also used for breathing. The scalene lifts the first rib, and when it’s tight will reduce the thoracic outlet.
Pectoralis minor is a chest muscle, which lies underneath the pectoralis major. When it’s very tight, it will compress the neurovascular bundle (nerves and vessels) supplying the arm against the ribs.
When you stress breathe a lot, have poor posture, or have suffered a neck injury, the scalene muscles can become very tight. When this happens, you may develop scalene trigger points. This may, in turn, lead to the scalene muscle being so tight it compresses the nerves and vessels going to the arm.
This is one cause of pain shooting down your arm which can be missed, though it is very important to rule out other causes of this symptom – like angina or prolapsed vertebral discs in the neck.
The first thing you can do to treat this muscle is to look for trigger points in the scalene and pectoralis muscles.
The scalene muscle has three muscular branches. The nerve bundle supplying the arm passes in between the anterior and the medial branches, so when they are very tight this can cause nerve compression. This is why releasing trigger points and stretching this muscle becomes very important if you have pain shooting down your arm.
It’s also important to find and treat pectoralis minor trigger points, as active triggers here can cause compression.
The easiest way to do this is to use our free trigger point charts tool. Once you’ve located active trigger points, you can turn them off with a self massage technique that uses ischemic pressure.
It’s also important to look for other causes of tension in these muscles, including poor breathing habits, and bad posture. If you have posture with your chin forward, shoulders slumped, this can increase thoracic outlet syndrome.
If thoracic outlet syndrome is being primarily caused by having an extra cervical rib, this may need to be moved surgically.
Sometimes thoracic outlet syndrome can be combined with other issues, like shoulder impingement, rotator cuff tears, and extensive tightness in the shoulder muscles. In this case, you may have more widespread pain in your shoulders, which obscures the cause of the outlet syndrome.
Many people find they get fast relief doing this. Another option is to use a nerve stretch, which you can see when you watch the video below.
Above is an exercise you can do to relieve nerve pain and tension running down your arm.