My physiotherapist today asked me to lay flat on a plinth and nod my head. She asked me to put my hand on my neck and feel the moving of the Sternomastoid, a large pair of muscles in the superficial layer of the neck. She then told me to nod trying not to use these muscles. This is an exercise for the deeper muscles which are attached to the spine responsible for refined movements. Movements using the Sternomastoid are too broad brushed.
I have never realised the control of neck movements can be so complex.