Comprehensive CT analysis of the morphometric and morphologic characteristics of mastoid and occipital emissary canals

Abstract Objective High-resolution computed tomography (CT) has significantly enhanced the visualization of small bony structures of the cranial base, enabling accurate assessment of emissary canals that connect intracranial and extracranial venous systems. Despite their clinical importance, posterior cranial fossa emissary canals exhibit considerable anatomical variability and may be overlooked or misinterpreted on imaging. A precise CT-based morphometric evaluation is therefore essential to improve radiological interpretation and surgical safety. The aim of this study was to evaluate the morphometric and morphologic characteristics of the mastoid emissarycanal (MEC) and occipital emissary canal (OEC) in the posterior cranial fossa, and assess their prevalence,dimensions, and anatomical variations in relation to age and gender. Method A cross-sectional CT analysis of 120 patients (47 females, 73 males) was performed. Prevalence, bilaterality, and accessory canals were recorded. Canal length, diameter, and foramen size were measured in axial views. Statistical comparisons and multivariate analyses assessed associations with demographic factors. Results MEC was present in 92.5% of scans, predominantly bilateral (95.5%), with accessory canals in 58.6% of cases. OEC was seen in 37.8% with no accessory canals. Median values are the following: foramen diameter 0.78 mm, canal length 8.12 mm, canal diameter 1.04 mm. No significant gender or age differences were observed. Conclusion MEC and OEC show high anatomical variability, underscoring the importance of accurate identification in surgical and radiological practice to prevent misdiagnosis and complications.