3-DIMENSIONAL FETAL CEPHALOMETRY

Craniofacial growth has been the subject of numerous studies in which different techniques have been elaborated aiming to model this dynamic phenomenon in a rational manner, One of the methods employed is cepha lometric analysis applied to the fetus, Generally, however, these stud ies are confined to the exploration of a single spatial plane (sagitta l plane), whose orientation is never defined in a rigorous and perfect ly reproducible manner, Thus, none of these analyses offers a formal g rowth model, This has led us to propose a new method of fetal cephalom etric study taking into account criteria for proper reproducible analy sis: spatial exploration of the head performed through three-dimension al tomodensitometric images and precise location of landmarks and repr oducibility of the orientation of each image, which is assured by refe rence to the vestibular orientation (based on the external semicircula r canals), as has been described by Girard and Perez and further devel oped by Fenart. When the labyrinth is developed, this orientation does not change during the growth stages of the head, even with craniofaci al deformities, This permits application of this orientation on fetuse s and the superposition of images of different subjects, The methodolo gy is presented using two normal human fetuses, and the advantages of this computerized tool are discussed.