Shoulder Turns in TGM concern Flat, On Plane, Rotated. The Torso is related. For example, the players that have so called slice of "pie" at the Top have a different torso position, than those that do not, as advocated by the Stack and Tilt. The Stack and Tilt guys like a Zero Pie, with a steady head at the Top... which looks like 9-1-6.
These types of things along with matching the hip slants, which is mostly controlled by the Knees... is what I am talking about. More detailed Zone 1 info.
It also has to do with the spine bending to the side . . . check these knees . . . and check the level hips too . . . there ain't much head motion in this movement either . . . .
So the knees can "unbend" and the head stay centered AND the hips can move right and the head stay centered AND the spine can tilt left and the head stay centered.