Ethmoidal Arteries and Ethmoidal Foramina: A Cadaveric Study of Their Anatomical Variations and Surgical Importance.

The ethmoidal arteries originate from the ophthalmic artery and traverse the medial wall of the orbit to reach the paranasal sinuses through the ethmoidal foramina. These arteries can become important obstacles for the surgery of the medial orbit, most notably during the endoscopic endonasal approach of the orbit. The lesion of these arteries during surgery can lead to severe complications such as retrobulbar hemorrhage and loss of vision. A correct anatomical knowledge of the variations of the ethmoidal arteries is vital to perform precise and safe surgical procedures in the medial orbit. The aim of this study is to increase the anatomical knowledge of these arteries and their respective foramina. In order to perform this study, the ethmoidal arteries were dissected in 22 cadaveric hemiheads fixated in 10% formaldehyde solution. The orbital roof was removed to access the orbital content. The ethmoidal arteries and their respective foramina were identified. Morphometric measurements were taken through the use of microrulers. The ethmoidal arteries were identified in all specimens. In 73% of cases, there were 2 ethmoidal arteries, in 23% there were 3 ethmoidal arteries, and in 1 case (4%) there was only 1 ethmoidal artery. The posterior ethmoidal artery was observed in 96% of cases. The anterior ethmoidal artery was observed in all cases. The middle ethmoidal artery was observed in 23% of the cases.