If I recall correctly, it was any stretch of the scalene muscles because they are attached to the first rib. The concern is that the first rib will be pulled further higher and reduce the space between the collar bone and the rib.
If you do a Google image search on "scalene" you will see which muscles these are and what they attach to. You can also watch the video. Also there is a text transcript below the video. It includes this:
Quote:
|
... stretching, or lateral bending, neck rotation exercises, and flexion exercises actually lift the ribs and make it worse. This is something that I don’t recommend; in fact, it’s contraindicated, and if you do it, you are not going to get any better. ...
|
(He also emphasizes that the patient must correct all postural problems that are involved or they will not get better permanently.)
On the other hand, the physical therapy (PT) people seem to recommend stretching those muscles in order to loosen them.
I am neither a chiro nor a PT and am only sharing what I've been hearing. Since I'm trying a chiro and he stated that side neck stretches were off limits, I'm following that course of advice.
Best regards.