This can be a very complicated subject. The literature is all over the place on this topic. In my 30 plus years of treating this condition, I have run across no less than six causes. Three of which I have not seen any significant degree of information on in chiropractic literature. The 1st is hypertrophy of the scalene muscles. Look at the first picture to the right and just imagine the muscles being oversized and squeezing the nerves as they pass between the scalene muscles before forming the brachial plexus. This type TOS is seen in individuals who work overhead looking up all day for a living. The 2nd is due to chronic inflammation at the level of the nerve roots on one side of cervical spine which also incorporates the first rib into that complex (no picture). The 3rd is advanced cervical DJD with a pronounced forward head resulting in severe IVF encroachment. (See Bottom of Page)


The scalene 1st type is usually job related and not a straight forward Chiropractic case. If you suffer from this form of TOS you must consider changing vocations along with Chiropractic and possible injections into selected scalene muscles by a specialist in that field. The  2nd  type should be straight forward in any Chiropractic office but I have observed a lack of attention given to the first rib while doing fill in work at dozens of offices. The 3rd type due to advanced cervical DJD ect., responds dramatically if properly treated, isn't well recognized in Chiropractic literature. I feel strongly the DJD type is not being treated in most offices. Before that discussion, here are brief descriptions the other more common forms of TOS.

Adhesions of the sheath surrounding the brachial plexus as it passes under the pectoralis minor causes a thoracic outlet syndrome marked by the hand quickly going numb with the arm extended over head. Second picture to the right. I have seen a couple cases of this type TOS and found them extremely challenging to fix. I believe micro surgery to be the answer if the adhesions proves to be primary.

Next is the cervical rib variety of TOS, which again does not respond well as the cervical ribs represent what is known as  space occupying lesions. Surgery may be indicated once identified. The third picture on the right with cervical ribs is representative. Cervical ribs don't always cause TOS, they are a fairly common anomalies and are actually extra ribs which should not be found in the neck at all.

​The last form of TOS worth discussion is the most common form of TOS which is a complex involving the clavicle, first rib and the brachial plexus. This form is usually  treated successively in most Chiropractic office unless the rib is primary and goes unaddressed. See forth picture on the right

The literature also lists other anomalous conditions such as Klippel-Feil, elongated C7 transverse processes, anomalous insertion of the scalene muscles or anomalous course of the nerves passing through instead of between scalene muscles, fractures, tumors and other space occupying lesions, exostosis from several processes  and other disease processes which I will not cover here.

The advanced DJD IVF encroachment tos

The TOS I wish to mainly discuss is poorly understood and poorly recognized by both MDs and DCs alike. As such, I believe it is important to discuss it here. This type is easy to recognize if you know what you are looking for. Maybe it's you, maybe it's a friend you know. They will be advanced in age and will spend a lot of time reading, studying or researching with their head held forward of their shoulders several inches. They generally look like this woman but with less of a Kyphotic thoracic spine. They develop a gradual worsening in their hands bilaterally which starts as tingling (paresthesia) then over time can progress to numbness with progressive loss of grip strength. To understand why this is happening you must learn some anatomy - I am sorry about that. Ready?   

The holes the nerves pass out of in the cervical spine are formed by grooves in the bone above and below. The hole is called an intervertebral foramin or an IVF. It's important to note that the IVF point anteriorly (forward) towards the convexity of the cervical curve. So the greater that convexity (or lordosis) is in the neck the larger the holes are that the nerves pass out of. Think of holes in a belt bending away from your eyes and you will notice the holes stay open. Now bend the belt in the opposite direction and you will notice the holes get smaller. Now imagine the holes (IVFs) are each made by two separate solid objects and you can immediately understand the dramatic change in the sizes of the holes during similar movement. Next realize those holes are where your delicate nerves exit your cervical spine to form your brachial plexus. Getting the picture? Decreasing, straightening or reversing the cervical curve dramatically decreases the size of the IVFs. A forward head can straighten or even reverse a cervical curve and is the fastest way I can think of to reduce the size of the IVFs. This is why Chiropractors are so interested in the curve of your neck. In a nut shell, the IVF remain largely patent (open) with happy nerves passing out of them because of the curve of the neck and the heights of the discs between the bones.


Okay, you are doing great. Now imagine what happens with degenerative changes in the cervical spine which brings the bones closer together or grows new bone into the IVF spaces. This directly decreases the size of the IVFs. Now add it all together. A forward head can literally do everything possible to decrease IVF spaces except decrease the disc heights and grow the new bone. Loss of curve or reversal of that curve due to a substantial forward head plus advanced degenerative changes equal IVF spaces closed literally to the point where the bone is crushing the nerves before they can even exit the spinal area. The result - progressive loss of sensation and grip strength to the point the hands get numb and incapable of even gripping a cup to get a drink.

This is strictly a regional technique issue in my opinion and experience. More to the point I have never seen another Chiropractor treat or an instructor even mention this type of TOS. The good news - if this is you or a friend of yours improvement with restoration of sensation and grip strength is usually rapid when properly treated utilizing biophysics.