METRIC CHARACTERIZATION AND EVALUATION OF THE DISTINCTIVE MORPHOLOGICAL FEATURES OF THE GREATER SCIATIC NOTCH ON A RECENT ITALIAN SAMPLE OF KNOWN SEX

Abstract Vladimir Novotný’s approach to identifying skeletal sex entails a deep understanding of anatomy in relation to the evolutionary implications and adaptive constraints that determine the differentiation of the pelvic region in humans. Considering the sacroiliac and ischiopubic traits as regions that are evolutionarily and functionally distinct leads to a better understanding of the significance of the pelvis structures in relation to sexual dimorphism. Although optimal diagnosis implies the whole combination of the characters in the two districts, some features of the pelvis, such as those in the ischiopubic district, are more informative. Among the structures of the sacroiliac district, the greater sciatic notch has been widely analyzed, but it is difficult to assess since its size and morphology may vary greatly due to its dependence on two anatomical subsystems. To facilitate the analysis, Vladimir Novotný, in his “ideal shape analysis of form” formalizes the evaluation of the morphology of the greater sciatic notch by identifying three essential features that define its general architecture: length and proportion of the branches, symmetry of the branches, and recurvate course of the superior ramus of the notch. These three features are visually evaluated and then scored in order to reduce the level of subjectivity of the diagnosis. These features can be quantified through conventional and geometric morphometric procedures. It was therefore verified whether morphometric characterization can detect the information expressed through these three features of the morphology of the notch and whether it may be used for diagnostic purposes. To this end, metrical and morphological characterization of the great sciatic notch was carried out for a series of recent coxal bones from a collection housed at the Istituto di Medicina Legale at Bari University (Italy). A total of 171 isolated coxal bones all belonging to 92 identified adult skeletons (45 males and 47 females) were considered for the study. The projective image of the greater sciatic notch contours in the trait was analyzed, from the base of the ischial spine to the top of the piriform tubercle, both as a whole and by separating the anterior and posterior branches. The sample was initially characterized metrically on the basis of linear and angular measurements, but also by evaluating the development of the branches and the areas underlying them. The data obtained were then used to perform multivariate exploratory and discriminant analysis. By using variables extracted from the notch as a whole and separately from the two branches, certain discriminant functions able to correctly sex between 90% and 93% of cases were defined. Overall differences in shape were also visualized by changes between configuration landmarks. The variables that were most effective in the analysis were re-considered and discussed.