Active Range of Motion (AROM) — The movement a joint achieves when the person moves it on their own, without assistance.
Cervical Spine — The neck region of the spine, composed of seven vertebrae (C1–C7).
Flexion — Bending the neck forward, bringing the chin toward the chest.
Extension — Bending the neck backward, looking upward.
Lateral Flexion — Tilting the head sideways, bringing the ear toward the shoulder.
Rotation — Turning the head to look over the shoulder.
Neutral Position — The natural, relaxed, forward-facing head position used as the measurement reference.
Normative Values (Norms) — Published reference values representing typical ROM for a given age group, derived from Youdas et al. (1992) and AAOS standards.
Trunk Compensation — Unwanted torso movement during neck testing that may inflate measurements.
Endpoint — The maximum comfortable limit of movement in a given direction.
Calibration (Baseline) — The initial phase where the system establishes your neutral head position.
Plateau — A period of stable hold at peak ROM, used to capture the endpoint measurement.
Landmark Detection — Automated identification of facial and body reference points using the device camera.
Plateau Average — The mean angle during the stable hold period at an endpoint.
Plateau SD — Standard deviation of the angle during the hold; lower values indicate steadier holds.
Transition Slope — The average rate of angle change (°/s) during movement between positions.
