"The Accessory Ethmoidal Canal Does Not Necessarily Contain an Arterial Structure"

Introduction: The aim of our study is to describe the prevalence of the accessory ethmoidal artery in endonasal endoscopic cadaver dissections and to identify its intraorbital origin. Material and Methods: From 2018 to 2020, thirty-four nasal dissections were performed in seventeen adult cadaveric heads. We performed a complete ethmoidectomy to identify the ethmoidal canals. Then, we removed the bony canal and the lamina papiracea to verify the injected vessel and to confirm the vascular structure inside the canal. Results: We found the anterior ethmoidal canal (AEC) and the posterior ethmoidal canal (PEC) in 100% of nasal cavities (34/34). We identified 4 accessory ethmoidal canals (AcEC) in the 34 nasal fossae dissected (12%). All AEC contained an arterial vessel. The AcEC contained an arterial vascular structure in 2 cases, a neural structure in other specimen, and in the fourth case no structure could be verified. In 32 of 34 nasal cavities, the PEC contained an artery and only in 2 cases the PEC did not contain any vascular structure. In these specimens, we observed that the AcEC with an arterial vessel inside (6%) was closer to the posterior canal than the anterior canal. Conclusion: According to our findings, we can suggest that the presence of a canal does not necessarily imply the presence of an arterial vessel, and that presence of the accessory ethmoidal artery could be associated with the absence of posterior ethmoidal artery.