In part 2 of their report, the authors continue to evaluate myoelectric data obtained from spinal motion dynamics involved in clinical rotation tests. They add to the ipsilateral regional analysis of motor performance as previously presented and analyze the total bilateral myoelectric activity gathered concurrently at individual thoracic vertebral segments during simultaneous rotation left and right motion tests. The authors' hypothetical consideration concerns the nature of composite behaviors at these vertebral segments during active and passive motions and the role that postural dynamics play in movement function. They consider these concepts in the context of the study's experimental design and also within the broader concept of the osteopathic musculoskeletal examination. Results revealed pronounced similarity in individual spinal electromyographic patterns whether motions were volitional or physician induced. Analysis demonstrates the bell-shaped myoelectric behavior pattern originally reported in part 1. The authors also discuss a functional model for this myoelectric activity involving a helical spinal motor pattern with a focal area of transition that is dynamic in response to postural and motion demands.