Is the preauricular groove, as defined by Bruzek (2002), an indicator of parity? A test using the SIMON identified skeletal collection (Vaud, Switzerland)
Abstract
The aims of this study are first, to test the relevance of the three non-metric traits in the preauricular region established by Bruzek (2002) for identifying the female population, and second, to test the relationship between the morphology of the preauricular area and parity. Age and pelvic dimensions are also analysed as potential contributing factors.
The group under study, derived from the SIMON identified skeletal collection (Vaud, Switzerland), comprises individuals living at the end of the 19th and in the first half of the 20th centuries. The sample consists of 504 coxal bones (including 236 pairs) from 268 individuals (133 females and 135 males), aged 16 to 81, with age classes equally represented.
The obstetric history is known for a subgroup of 99 females. Using the three visual criteria employed together, the results of sex estimation indicate that both the indeterminate rate (11.3% for observer 1 and 7.7% for observer 2) and the classification error rate (2.2% and 9.2%, respectively) are low.
The study then shows that the preauricular groove, as defined by Bruzek (2002), is present in significant proportions in both nulliparous females (73.8%) and females who have given birth (79.8%), and that therefore it cannot be considered an indicator of obstetric history. The number of children does not seem to be an explanatory factor, but age contributes to the shaping of these bony imprints.
The preauricular groove is already recognizable in close to 60% of females aged 16 to 39 years, but the bony changes are more marked with increasing age, leading to a decrease in both sex diagnostic error and indeterminacy. Correlation between a hyperfeminine morphology of the pelvis and a highly feminine development of the preauricular area may indicate a biomechanical contribution.