Procedure for the systematic orientation of digitised cranial models. Design and validation.
Comparison of bony pieces requires that they are oriented systematically to ensure that homologous regions are compared. Few orientation methods are highly accurate; this is particularly true for methods applied to three-dimensional models obtained by surface scanning, a technique whose special features make it a powerful tool in forensic contexts. The aim of this study was to develop and evaluate a systematic, assisted orientation method for aligning three-dimensional cranial models relative to the Frankfurt Plane, which would be produce accurate orientations independent of operator and anthropological expertise. The study sample comprised four crania of known age and sex. All the crania were scanned and reconstructed using an Eva Artec™ portable 3D surface scanner and subsequently, the position of certain characteristic landmarks were determined by three different operators using the Rhinoceros 3D surface modelling software. Intra-observer analysis showed a tendency for orientation to be more accurate when using the assisted method than when using conventional manual orientation. Inter-observer analysis showed that experienced evaluators achieve results at least as accurate if not more accurate using the assisted method than those obtained using manual orientation; while inexperienced evaluators achieved more accurate orientation using the assisted method. The method tested is a an innovative system capable of providing very precise, systematic and automatised spatial orientations of virtual cranial models relative to standardised anatomical planes independent of the operator and operator experience.
Grupo IDERGO Escuela de Ingeniería y Arquitectura Edificio Torres Quevedo C/María de Luna 3 50018 Zaragoza, Spain. Electronic address: martabbarrena@gmail.om.
M
M
Bailo
Instituto de Medicina Legal de Aragón Calle del Nuevo Parque 50015 Zaragoza, Spain.
S
S
Baena
Grupo IDERGO Escuela de Ingeniería y Arquitectura Edificio Torres Quevedo C/María de Luna 3 50018 Zaragoza, Spain.
J J
JJ
Marín
Instituto de Medicina Legal de Aragón Calle del Nuevo Parque 50015 Zaragoza, Spain.
J M
JM
Arredondo
Grupo IDERGO Escuela de Ingeniería y Arquitectura Edificio Torres Quevedo C/María de Luna 3 50018 Zaragoza, Spain.
J M
JM
Auría
Grupo IDERGO Escuela de Ingeniería y Arquitectura Edificio Torres Quevedo C/María de Luna 3 50018 Zaragoza, Spain.
B
B
Sánchez
Grupo IDERGO Escuela de Ingeniería y Arquitectura Edificio Torres Quevedo C/María de Luna 3 50018 Zaragoza, Spain.
E
E
Tardío
Instituto de Medicina Legal de Aragón Calle del Nuevo Parque 50015 Zaragoza, Spain.
L
L
Falcón
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D059925:Anatomic Landmarks; D003198:Computer Simulation; D005260:Female; D018732:Forensic Anthropology; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D015588:Observer Variation; D012886:Skull / Q000033:anatomy & histology*
Anthropology; Assisted procedure; Cranial 3D scanning; Cranial anatomic orientation; Forensic anthropology population data; Frankfurt Plane