[Jeff]

The red line doesn't represent the spine angle. It represents a line drawn from a point just above the lower swing center (midpoint between the pelvis) and the center of the head, and it roughly represents the slant of the upper torso away from the target. I think that the spine is situated behind the red line, but very close to being parallel to that line.

Here is a view of Hogan from behind and one can clearly see his rightwards tilted spine, although his right thigh slants left-upwards -that gives him the reverse K position.



One can see where his lower lumbar vertebrae are, and roughly where the base of the neck is situated. A straight line drawn between the lowest lumbar vertebrae and the base of the neck has a rightwards tilt and therefore the spine must have an overall rightwards tilt. However, the upper thoracic spine is always verticalised in a golfer who has a big shoulder turn that torques the upper thoracic spine. That gives the spine a S-shaped (spiralised) appearance, which often leads to unresolved debate about where the spine is precisely located.

Jeff.