Statistical shape analysis, a relatively a new method for biological research, compares body forms by using specific landmarks determined by anatomical prominences. In this study, we aimed to identify normal facial asymmetry between the right and the left sides of the face. Facial landmark data were collected from two-dimensional digital images of 321 young healthy subjects (150 males and 171 females). These data were analysed using Euclidean distance matrix analysis. The number of significantly asymmetric linear distances between the two halves of the face was greater in females than in males. We found that the left side of the face was most commonly dominant in both males and females. Such data may be useful in establishing a database for future similar studies.

A statistically significant difference was found between males and females in 20 of 27 measurements taken (p < 0.001). The most prominent differences between the sexes were observed in the measurements taken from the face region. Results were compared with other ethnic groups.

Sexual dimorphic characteristics, which play an important role in human evolution studies and biological research, can be studied morphologically and metrically. Geometric morphometrics allows a better assessment of morphological characteristics. Statistical shape analysis has a long history in neuroanatomical and other research. The aim of this study was to identify shape differences of the corpus callosum between genders. Landmark coordinate data were collected from two-dimensional magnetic resonance imaging scans of 93 homogeneously aged patients, 45 men and 48 women. These data were analyzed using Euclidean distance matrix analysis and thin plate spline analysis. The general shape variability of the corpus callosum of men was greater than that of women (men, 0.134; women, 0.097). We found no significant difference between sexes in the general shape of the corpus callosum, but we did find significant differences in the distances between some landmarks. Deformation of the corpus callosum between men to women was mainly detected in the posterior of the corpus callosum. These results serve as a reference for future studies on shape alterations of the corpus callosum associated with certain conditions. Anat Rec, 290:825-830, 2007. 2007 Wiley-Liss, Inc.Key words: corpus callosum; sexual dimorphism; statistical shape analysis; geometric morphometrics; EDMAThe corpus callosum (CC) is the major commissural pathway between the brain hemispheres and plays an integral role in relaying sensory, motor, and cognitive information from homologous regions in the two hemispheres. Many neurological studies indicate that the size and shape of the CC are related to gender, age, and neurodegenerative diseases, among other factors. The sexual dimorphism of the CC has been reported from postmortem and magnetic resonance imaging (MRI) studies, but this conclusion has remained controversial since the original report by DeLacoste-Utamsing and Holloway (1982), who found that adult human women had a larger splenium.Statistical shape analysis, a relatively new method in biological research, compares body forms by using specific landmarks determined by anatomical prominences.

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