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The Subclavius Muscle – The Single Most Super Contracted Muscle of Thoracic Outlet Syndrome

Muscle Origin: The subclavius originates from the junction of the first rib and its cartilage.

Muscle Insertion: The subclavius inserts on the inferior surface of the middle of the clavicle.

Muscle Action: The subclavius action is to depress the clavicle (collarbone).


When the subclavius is in an abnormally contracted state, it draws the clavicle (and hence the shoulder) down and forward. It also lifts the first rib up into the thoracic outlet.

The subclavius muscle is the only muscle that can compress the interscalene triangle, the costoclavicular, and the subpectoral space!

I find incredibly inflamed subclavius spasms, which are the most difficult to reprogram, in 100 percent of the cases with thoracic outlet syndrome cases.

Why isn’t this muscle included in almost all the articles on non-surgical treatment of thoracic outlet syndrome?

Why aren’t doctors cutting this muscle out with patients with thoracic outlet syndrome?

You never see it mentioned with respect to doctors injecting it with analgesics as part of the treatment for compression of the thoracic outlet area.

In my many years of examining the muscles in this area, the painful spasms of the subclavian muscle are the most consistent and persistent spasms that pulled the collarbone down into the thoracic outlet. Also, the subclavius muscle swelling expands the thickness of the muscle, which causes narrowing and possible compression of the nerves and blood vessels underneath.

Common activities that stimulate the sustained contractions of your subclavius muscles, pectoralis minor muscles, the coracobrachialis, and biceps short head muscle to contract are when you reach out your arm to work with something for a long duration.

Sustained contraction of the shoulder muscles can cause trigger points and super contractions that will depress the shoulder down into the thoracic outlet and tunnel, causing not only symptoms related to thoracic outlet syndrome but even symptoms that mimic a heart attack.

If you understand thoracic outlet syndrome, you know the focus is on treatment and surgical resection (removal) of the pectoralis minor. The pectoralis minor is NOT the main muscle that causes compression of this area.

If you look at the origin, insertion, and action of the biceps short head, the coracobrachialis, the pectoralis minor, the latissimus dorsi, the lower trapezius muscles, and the subclavius muscle, you will find they all depress the shoulder down into the thoracic outlet. In my opinion, it is just the muscle that is the easiest to surgically remove without so much permanent weakness in the shoulder girdle.

I have found that the subclavius muscle is one of the most responsible muscles for compressing the costoclavicular space.

Researchers from the Tokyo Medical and Dental University in Tokyo, Japan, found the aberrant subclavius muscle, which connected the first costal cartilage and the superior margin of the scapula on postmortem examinations (cadaver dissections). It’s normally connected to the collarbone. They found that this muscle was present in 8.9 percent of the 124 cadavers they checked, which is a lot (6).

They recommended doctors take into account the possible existence of such an aberrant muscle during the examination of patients with thoracic outlet syndrome, especially in those with symptoms of venous compression because it runs right over the top of the subclavian artery and brachial plexus (nerves that supply the arm) (6).

Now don’t all go out and get an MRI to see if you have this muscle thinking it is the cause of your thoracic outlet syndrome. If it is not in a spasm then it’s not compressing the vein or nerves even if it’s lying on top of them.

If your doctor is thorough at examining the 10 muscles which can compress the outlet for spasms they will find it, treat it with my treatment approach in chapter 13 and it will stop compressing the outlet.

Dr James Stoxen DC examining for tension, spasm, splinting and pain in the subclavius muscle. This is the best approach for treating the subclavius muscle.
This is the position to place your thumb to self treat your subclavius muscle.
This is the position to use the Massage Assist Pro Sports Vibrating Massager on the subclavius muscle

If you cannot find a doctor or therapist to do vibration massage or enough deep tissue on you to get the relief you need, or if you are tired of paying others to do this for you then buy the Massage Assist and do it yourself.

Call our office and lets talk this out.
773 735 5200

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