Quantifying the Shape of the Greater Sciatic Notch Using Elliptical Fourier Analysis

Abstract

The greater sciatic notch is a well-established, sexually dimorphic feature in humans. The traditional anthropological perspective describes females as having wide and shallow notches, while the male notch is described as being narrow and deep. However, the size and shape of the notch can vary between populations, which can complicate the use of this feature as a sex determinant in forensic analyses. The current study investigates the relative contributions of sex, ancestry, and age at death to the shape of the greater sciatic notch using a morphometric approach called elliptical Fourier analysis (EFA). The study sample includes 975 dry bone specimens obtained from three skeletal collections, including three ancestral groups. The results indicate that the notch varies systematically with each of the aforementioned variables, with sex having the greatest contribution. While classical anthropological descriptions of notch shape differences between the sexes arepartially confirmed, the relationship between sex and notch shape is more complex than previously assumed. Females tend to displayshallow and symmetrical notches, while those of males are deep, asymmetrical, and tend to demonstrate a piriform tubercle. A smallerproportion of the variation in notch shape is attributable to the other variables. The results for ancestry indicate that African Americanstend to have short and narrow notches, while European Americans tend to exhibit short and wide notches. Chilean notches tend to be tall and wide. When considering age at death, the notch appears to deepen and widen with increasing age, suggesting that the changes are resorptive rather than depositional.