Anomalous Foramina Through the Greater Wing of the Sphenoid Bone: A Radio-Anatomical Study on a Cohort of Dry Skulls from the Interbellum Period Using MDCT.

Background: The foramen of Arnold (FA) and foramen of Vesalius (FV) are two inconstant small openings through the greater wing of the sphenoid bone. When FA is present, the lesser petrosal nerve passes through it. FV usually contains an emissary vein that connects the cavernous sinus to the pterygoid plexus. Objectives: To assess the presence, unilaterally or bilaterally, of the aforementioned inconstant foramina in order to gain a better insight into the anatomic variability of the middle cranial fossa. Methods: We analyzed five hundred random unenhanced CT examinations of human dry skulls from the "Francisc I. Rainer" Craniological Collection of the Human Anthropological Institute in Bucharest, Romania. The collection holds substantial anthropological and radiological value, as dry skulls allow the use of higher spatial-resolution imaging parameters and thus better detection of the small osseous structures. All scans were performed on the same Multi-Detector Computed Tomography (MDCT) scanner (Canon Aquilion One 64 slice, Canon Medical Systems Corporation) in the Department of Radiology of the Bucharest Emergency University Hospital. After collecting data, appropriate statistical analysis was performed. Results: FA was absent in 355 (71%) skulls and present in 145 (29%) skulls, bilaterally in 33 (6.6%) skulls, and unilaterally in 112 (22.4%) skulls. FV was absent in 151 (30.2%) skulls and present in 349 (69.8%) skulls, bilaterally in 223 (44.6%) skulls, and unilaterally in 126 (25.2%) skulls. Conclusions: The great variability in the prevalence of these foramina may be partly explained by the different methods of analysis of the skull base, as well as the different population subgroups on which the research has been focused. Knowledge of this variability holds great importance for anatomists, anthropologists, as well as clinicians who interact with this complex area.