A standardized nomenclature for craniofacial and facial anthropometry

Standardized terms and methods have long been recognized as crucial to reduce measurement error and increase reliability in anthropometry. The successful prior use of craniometric landmarks makes extrapolation of these landmarks to the soft tissue context, as analogs, intuitive for forensic craniofacial analyses and facial photogrammetry. However, this extrapolation has not, so far, been systematic. Instead, varied nomenclature and definitions exist for facial landmarks, and photographic analyses are complicated by the generalization of 3D craniometric landmarks to the 2D face space where analogy is subsequently often lost, complicating anatomical assessments. For example, landmarks requiring palpation of the skull or the examination of the 3D surface typology are impossible to legitimately position; similar applies to median landmarks not visible in lateral photographs. To redress these issues without disposing of the craniometric framework that underpins many facial landmarks, we provide an updated and transparent nomenclature for facial description. This nomenclature maintains the original craniometric intent (and base abbreviations) but provides clear distinction of ill-defined (quasi) landmarks in photographic contexts, as produced when anatomical points are subjectively inferred from shape-from-shading information alone.