Orbital Breadth Research Articles

New approaches to human facial morphology using automatic quantification of the relative positions of the orbital and nasal apertures.

The purpose of this study was to define and quantify the relative positions of the orbital and nasal apertures in the human face. The material consisted of 44 skulls (32 males, 12 females). For each skull, an image of the projection of the face was captured perpendicular to the palatal plane, using a CCD camera. The orbital and nasal apertures were segmented and characterized using classical image analysis procedures. New quantitative parameters were automatically determined from the centres of area of the facial apertures, and from horizontal and vertical lines of reference. Sexual differences were only significant for orbital height, nasal height, and orbitonasal height. A medio-lateral orbitonasal overlap, as well as a vertical orbitonasal overlap, existed in all individuals; the vertical overlap was always much more marked than the medio-lateral overlap. Significant proportions of the human face were also demonstrated: on average, the interorbital breadth corresponded to a fifth of the biorbital breadth, and thus to half of the mean orbital breadth; the nasal breadth corresponded to one fourth of the biorbital breadth, and the vertical orbitonasal overlap to one fourth of the orbitonasal height. Some instructive significant correlations were observed between these new parameters. The applications of the present methodology seem of great potential interest in anthropology and clinical biometry.

Craniometric sexual dimorphism inLeontopithecus Lesson, 1840 (Callitrichidae, Primates)

Lion tamarins are among the World's most critically endangered primates. Many studies have been produced under guidance of the International Management Committees for the preservation and management of these tamarins. Primates present morphological sexual differences in a wide range of characteristics, including cranial morphology. Studies of sexual dimorphism in the cranial morphology of theLeontopithecus are few in number and contradictory in their results. In order to check for the existence of sexual dimorphism in lion tamarins the present study analyzed 17 craniometric distances on 56 crania of three species of lion tamarins (Leontopithecus): 20L. rosalia (14 females and 6 males); 13L. chrysomelas (6 females and 7 males); and 23L. chrysopygus (8 females and 15 males). All crania are housed in the CPRJ-FEEMA collection (Primatological Center of Rio de Janeiro) and came from animals born in captivity.L. chrysopygus was more sexually dimorphic (10/17 measurements, 59%) thanL. chrysomelas (9/17 measurements, 53%) orL. rosalia (7/17 measurements, 41%). In all three species, male values are greater than the female ones, except for orbital breadth (m7) inL. rosalia. However, this distance is not sexually dimorphic in this species. This study reveals that some cranial distances, especially in the facial region, are sexually dimorphic in lion tamarins.

Measurement Errors in Craniometry

Although many data of cranial as well as other skeletal measurements have up to the present been accumulated in the field of anthropology, there can be seen few reports on their errors. In this article, the intra- and inter-observer errors of 22 measurement items, used frequently in Craniometry, were assessed and discussed.Intra- and inter-observer measurement error variances of each item were firstly obtained through the analysis of variance for balanced hierarchal classification based on the data which were provided by six observers measuring the same five male skulls of Edo era independently twice. As a result, the greater intra-observer error variances were recognized, especially, in minimum frontal breadth, orbital breadth and facial profile angle (Tables 1 and 2). The significant systematic errors due to observers were found in eight of the 22 items, i, e., biauricular breadth, biasterionic breadth, orbital breadth and height, glabello-inion length, cranial base length, nasal height, and upper alveolar breadth (Tables 1 and 2).Secondly, it was ascertained by the principal component analysis that there was no common error source among the 20 linear measurement items. Finally, the cluster analysis of the present sub-samples for assessing measurement errors and several samples from literature suggested that errors, especially inter-observer, might greatly affect the interpretation for the results of population studies (Fig, 1).From the above, it was re-realized that any result based on measurements should carefully be interpreted taking their errors into account.