MWM and the 1st and 2nd ribs.

Brian Mulligan: “When these are involved, patients often experience pain along the trapezius muscle between the neck and shoulder when side flexing away from the side of pain.

Stand behind the patient, fixate the first (or second) rib antero-laterally with one hand, while you, with your free hand (or the patient) apply overpressure to the head after the patient has side flexed away. When this is indicated there will be no pain and after 6-10 repetitions, they should be pain-free. “

Source:  Manual Therapy, NAGS, SNAGS, MWMS etc. by Brian R Mulligan, 7th edition.

Watch video clip F.4. in the app.