CT-based morphometric analysis of the zygomatic region: infraorbital foramen localization, bone thickness, and sutural relationships.

BACKGROUND: The zygomatic region is surgically important because its bone architecture and relationships with the infraorbital foramen (IOF), coronoid process (CP), and maxillary sinus (MS) influence anatomical orientation during implant placement, fracture fixation, and osteotomy procedures. However, these structures have generally been evaluated separately, and integrated computed tomography (CT)-based assessment using standardized sutural landmarks remains limited. This study aimed to establish a CT-based morphometric framework for the zygomatic region and evaluate anatomical variation by sex, age, and side. METHODS: Paranasal sinus CT examinations of 362 fully dentate adults (184 men and 178 women; 18-85 years) were retrospectively analyzed bilaterally using multiplanar and three-dimensional reconstructions. IOF surface quadrant location and distances from the zygomaticomaxillary suture (ZMS) endpoints, cortical and medullary zygomatic bone thicknesses at a standardized ZMS level, and distances from the zygomaticotemporal suture (ZTS) to the CP and lateral wall of the MS were assessed. Generalized estimating equations, chi-square and Bowker tests, and observer reliability analyses were performed. RESULTS: All seven continuous parameters were greater in men than in women (all p < 0.05). Significant right-left differences were small. Older age was associated with a greater ZMS inferior endpoint-to-IOF distance and with lower anterior and posterior cortical thicknesses. The IOF was predominantly located in A1 (71.8%) and was absent from the lateral quadrants; A3 localization was more frequent in women and younger adults. Progression toward A3 corresponded to increased superior and decreased inferior ZMS endpoint-to-IOF distances (both p < 0.001). Anterior and posterior cortical thicknesses were moderately correlated (ρ = 0.59). Measurements and quadrant classification demonstrated good-to-excellent reliability. CONCLUSIONS: Surface-based IOF mapping and standardized sutural measurements provided a reproducible framework integrating IOF localization, regional bone architecture, the CP, and the lateral wall of the MS. These reference values may provide an anatomical reference for CT-based preoperative assessment and planning in zygomatic implant placement, midfacial fracture fixation, and osteotomy procedures.