This is an interesting pattern as I usually only see a few cases a year of it but have seen a lot of it this year. Research also speaks of it as being a less frequent pattern, so why are there so many more cases of it in my practice now?
When I ask them if there is a motion that they can use to reproduce it, they crook the elbow slightly, hold their arm up at shoulder level and turn it like they are steering a car. They often remark that it bothers them when they hold their arm on the steering wheel for a long period or if they cross mid-line.
Some weightlifters also complain of this when doing lat pull-downs or shoulder presses. People also complain of this when they sleep on that shoulder with the arm extended so that the elbow is above their head.
There isn’t a lot of home care with lasting results but you can get some relief with gentle stretching under a hot shower and avoiding the activities mentioned in the section above. You should avoid sleeping on this side with the elbow in front of the body.
The stretch for this is to raise the arm above your head while in the showering with hot water directed at the back of your arm pit. These should be gentle stretches that less than 2 seconds and are repeated more than 4-5 times. Rotating your arm so that your elbow faces back and your thumb faces forward extends this stretch.
This is not an easy problem to solve by yourself. It is almost always part of a more complex problem that involves other shoulder muscles, especially the rotator cuff muscles.
Teres Major is usually in a fascial sheath with latissimus dorsi. Its location in the arm pit makes it tough for many therapists to work. Ice and stretch or hot stones help to release it so that it is pre-released and compressions are easier. Direct work on the trigger points at the attachment on the humerus can be tedious because of avoiding neurovascular structures in that area.
Mobilizing the glenohumeral joint, the lower cervicals helps to produce easier treatment lasting results but when this muscle has become chronically symptomatic, it usually needs direct work to pull it out of its hyper-contracted state.
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.