Fig 3.

(A) Axial drawing depicting the thumb test for a right shoulder with placement of the examiner’s thumb over the posterior glenohumeral joint line, which creates a functional posterior “bone block.” (B) Axial drawing depicting the thumb test for a right shoulder with placement of the thumb over the posterior glenohumeral joint line. The examiner uses the fingers from the same hand to anchor to the anterior clavicle as a counterforce. (C) Sagittal drawing depicting the thumb test with the fingers anchored on the anterior clavicle.