ISO 8549 establishes a vocabulary of terms used in the field of external limb prosthetics and orthotics. This document defines general terms used to describe these prostheses and orthoses, and the personnel involved in the practice of prosthetics and orthotics. The complete range of levels of limb amputation are listed and defined in ISO 8549-2. The complete range of classes of orthoses are listed and defined in ISO 8549-3. This document does not apply to breast, ocular or other external prostheses used to replace other parts of the human body, nor to dental prostheses or orthoses. For the purposes of this document, the abbreviated term 'prosthetics' and its derivatives only apply to external limb prosthetics; the abbreviated term 'orthotics' and its derivatives only apply to external orthotics.