The preauricular sulcus has long been debated as a pelvic feature variably
attributed to obstetric stress, ligamentous traction, and broader biomechanical processes. To clarify its determinants, we analyzed 409 adult individuals from three archeological and one early modern skeletal collection from
the Iberian Peninsula, integrating graded sulcus expression with pelvic
morphology, body size, and demographic context. Sulcus expression shows
marked sexual dimorphism: females exhibit the full morphological spectrum, whereas males display limited variation and are overwhelmingly concentrated in the lowest grades. Hierarchical log-linear models and ordinal
logistic regression analyses indicate that preauricular sulcus presence is not
associated with stature, body mass, or overall pelvic canal dimensions.
Instead, inferior pelvic dimensions, particularly pubic length and outlet
measures, emerge as the only consistent morphological predictors, with significant sex-specific interactions restricted to the outlet. Neither population
affiliation nor age at death modifies the association between sex and sulcus
expression. Taken together, these results support a model in which the preauricular sulcus reflects sex-specific biomechanical environments of the
inferior pelvis rather than overall body size or population-level variation.
Within this framework, sulcus development is best interpreted as ligamentmediated remodeling shaped by localized mechanical loading and hormonally mediated changes associated with pregnancy, while remaining.
