Is the preauricular groove, as defined by , an indicator of parity? A test using the SIMON identified skeletal collection (Vaud, Switzerland)

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 19^th and in the first half of the 20^th 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.

Grooves in the preauricular area of the human ilium as indicator of sex or traces of parturition: historical background with a test of Novotný's method

This paper summarizes the history of the study of bone surface depressions near the contact surfaces of the sacroiliac joint, or grooves located below the linea terminalis, known in the literature as "scars of parturition" or "pelvic scars". Since the beginning of the 20^th century, the "sulcus praeauricularis" has been confused with the "sulcus paraglenoidalis" without a satisfactory explanation of their aetiology. Any groove in the preauricular area of the pelvic bone has been referred to as an indicator of female sex and used in sex estimation in a way that does not respect the nature of sex differences. Novotný (1979) included bone structures, which were described by various authors in both females and males, in his method of holistic evaluation. He proposed a three-step categorization for the evaluation of the bone surface of the pelvic preauricular area (three sub-characteristics scored independently) in order to distinguish the sulcus praeauricularis as a female trait from other structures that may occur in both sexes. However, Novotný's work did not become widely known. Testing of the Novotný method was performed in four groups of individuals of known sex without knowledge of the reproductive history of the females (Novotný 1981; Bruzek 2002; Mikešová 2008) and included a total of 852 pelvic bones (457 male and 395 female). The results showed that female morphology, which is characterized by the presence of various forms of sulcus praeauricularis, occurred in a total of 270 of 395 females (68.3%). Female morphology was found in only 5 of 457 males (1.1%). Male morphology was observed in 419 of 457 males (91.7%), but also in 11.1% of females (44 of 395). Indeterminate or ambiguous morphology was found in 33 of 457 males (7.2%) and 81 of 395 females (20.5%). The application of the Novotný method showed that of the total 275 specimens with female morphology, 98.2% were females and only 1.8% were males. It is therefore appropriate to use this reliable method to estimate the sex of skeletal samples. To test the relationship between morphology and obstetric history in females it is necessary to use a sample with known parity.

RANKL-Induced Increase in Cathepsin K Levels Restricts Cortical Expansion in a Periostin-Dependent Fashion: A Potential New Mechanism of Bone Fragility

Receptor activator of nuclear factor-κΒ ligand (RANKL) is necessary and sufficient to promote osteoclastogenesis and a key pathogenic factor in osteoporosis. Failure of periosteal apposition to compensate for bone loss due to endosteal resorption further contributes to bone fragility. Whether these two processes are biologically related, however, remains unknown. Using high-resolution peripheral quantitative computed tomography (HR-pQCT), we first examined cortical bone parameters at distal radius and tibia in postmenopausal women (PMW) as well as in cadaveric human adult humeri. Increases in medullary area were negatively correlated with cortical bone volume but positively with total bone volume, and this relationship was stronger in the dominant arm, suggesting a mechanically driven process. To investigate the role of RANKL in this dual process, we used mice overexpressing huRANKL (huRANKLTg⁺ ). Trabecular and cortical bone volume (Ct.BV) are reduced in these mice, whereas cortical total volume (Ct.TV) is increased. In these bones, Sost mRNA levels are downregulated and periostin (Postn) mRNA levels upregulated, hence providing a positive message for periosteal bone formation. In turn, genetic deletion of Postn in huRANKLTg⁺  mice prevented the increase in Ct.TV and aggravated bone fragility. In contrast, cathepsin K (Ctsk) ablation improved Ct.TV in both huRANKLTg⁺  and wild-type (WT) mice and stimulated periosteal bone formation, while augmenting Postn protein levels. Therefore, bone strength in huRANKLTg⁺ /Ctsk^-/- mice was restored to WT levels. These findings suggest that high levels of RANKL not only induce endosteal bone loss but may somewhat restrict periosteal bone formation by triggering periostin degradation through cathepsin K, hence providing a biological mechanism for the observed limited increase in cortical area in postmenopausal women. © 2021 American Society for Bone and Mineral Research (ASBMR).