Comparative Evaluation of Pterion Morphology and Morphometry in Dry Human Skulls and Craniolateral Computed Tomography: An Osteological and Radiological Study

Introduction: The pterion is a craniometric landmark overlying the anterior division of the middle meningeal artery and the lateral (Sylvian) fissure.Its variation is relevant to pterional neurosurgery and to the interpretation of cranial sutures on imaging.Osteological and computed tomography (CT) data obtained within a single study are limited.Objective: The objective of the study is to compare pterion morphology, and its distances from the zygomaticotemporal suture (Cp-ZT) and the frontozygomatic suture (Cp-FZ), between independent samples of adult dry human skulls and adult three-dimensional CT examinations, and between sides.Materials and methods: In this comparative cross-sectional study (April 2024 to October 2025), 118 adult dry skulls and 118 adult cranial CT examinations, obtained from different individuals, were assessed bilaterally (236 sides per dataset) after an a priori sample-size estimate.Each side was classified as sphenoparietal, epipteric, stellate, frontotemporal, or atypical.Cp-ZT and Cp-FZ were measured with a digital Vernier calliper on skulls and with the electronic calliper of the imaging software on CT reconstructions.Distributions were compared with the Pearson chi-squared or Fisher-Freeman-Halton exact test and distances with the independent-samples t-test (significance, p < 0.05).Results: The sphenoparietal type predominated in both datasets (dry skulls 61.0%; CT 68.6% of sides).The right-sided distribution did not differ between datasets (χ² = 6.00, p = 0.199), whereas the left-sided distribution did (χ² = 16.29,exact p = 0.002), chiefly because epipteric bones were recorded more often in skulls than in the CT dataset (22.9% vs 8.5%).Values below are dry skull vs CT.Cp-ZT was shorter in the CT dataset on both sides (right 33.83 vs 25.69 mm; left 31.88vs 27.10 mm; both p < 0.001).Cp-FZ was longer in the CT dataset on the right (26.66 vs 29.27 mm, p < 0.001) and marginally shorter on the left (25.75 vs 24.80 mm, p = 0.031).Conclusions: The sphenoparietal type predominated in both datasets and on both sides, and the right-sided distributions were similar.The left-sided distribution and the absolute distances differed between datasets.Because the skulls and CT examinations came from different individuals and the two measurement methods are not geometrically equivalent, these differences cannot be attributed to imaging modality alone and may also reflect population, age, and sex differences.The lower frequency of epipteric bones in the CT dataset is consistent with limited CT depiction of fine sutures, but this hypothesis needs testing on paired CT and osteological examinations of the same crania.Reference values from the two sources should not be combined without qualification.