This part of ISO 16840 applies to seating intended to provide postural support within a wheelchair. It specifies: a) a global coordinate system that permits the determination and recording of a person's posture while seated in a wheelchair; b) the standard terms and definitions for use in describing both the posture and the anthropometrics of a person seated in a wheelchair; c) the terms and definitions for describing the dimensions, location and orientation of seating support surfaces, which together comprise the body support system. This part of ISO 16840 does not specify any methods for use in measuring a person's seated posture, nor does it define terms for dynamic physiological movements (such as flexion or extension). This part of 16840 might be applicable to seating other than that intended to be used within a wheelchair.