People complain of pain along the inside of their shoulder-blade when reaching high above the head, to the back seat of the car or to adjust clothing behind the back. They have usually adapted their movements to avoid taking that arm too far back. They will insert that arm first into a coat. They will avoid having to tuck in their shirt by putting the pants on over the shirt. They will fasten the bra in front, turn it around and then carefully insert the painful arm under the strap first.
These same movements, which involve the infraspinatus muscle, may produce shoulder pain as described in this post. Those patterns of shoulder pain are more likely to bother people when sleeping on the shoulder than reaching overhead.
The tests to see if this muscle is the problem, involve those movements. The first one involves placing the forearm across the low back. The second one involves reaching around the back of your head to place your palm on your opposite ear. Restriction and pain in either of those activities indicate a problem. A few other muscles, especially coracobrachialis, may create pain and restriction in these movements. In that case, the pain pattern will be different.
There are a number of self-care strategies. You can stretch the arm across the front of your body while standing in the shower with the back of the shoulder under hot water. This is one of the most popular and effective strategies for temporary relief.
Some people use a tennis ball or other object to press into the back of the shoulder-blade. The trigger point that creates this pain is very close to the shoulder joint and without guidance, you could actually aggravate your condition.
If you can do it, sleeping on your side, with the arm behind you, helps the shoulder joint. Most people have trouble with turning over and such when sleeping like that. The most commonly recommended sleeping position is on your other side with the arm of the painful shoulder supported so that it is at a right angle from the body. Level 2 trigger points create pain on stretch and draping the arm down across the body creates a sustained stretch that eventually generates enough pain to wake you.
If a stretching program is consistent and well done, it can really help this problem. Often, the stretching routine that resolves this is more extensive and requires the guidance of an experienced practitioner. If this problem persists, see a bodyworker that knows shoulder work.
This trigger point is very close to the glenohumeral fossa and must be treated carefully. Mostly, consider that the trigger point is strongly associated with an anteriorly displaced humerus so that pressing forward on the humerus while treating this may create some immediate relief but create proprioceptive feedback that perpetuates the trigger point.
Also, many therapists treat this stubborn trigger point too early in the session. It should be prepped with cervical and shoulder work so that when it is addressed, it releases more completely and with longer lasting results. Work along the coronal suture is indicated for the craniostructural therapist.
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Tony Preston has a practice in Atlanta, Georgia where he sees clients.
He has written and taught about anatomy, trigger points and cranial therapies since the mid-90s.