A review of the ethmoidal foramina and their clinical application

The ethmoidal foramina (EF), located on the medial orbital wall along the frontoethmoidal sutures, are critical anatomical landmarks for surgeries involving the medial orbital wall. This review aimed to review the surgical anatomy of the EF, including their embryology and radiology. Although the frontoethmoidal sutures mostly have two foramina passing through them, there are reports of single foramen or multiple, up to six foramina. These foramina provide a passage for the ethmoidal arteries and nerves, branches of ophthalmic arteries and nerves. The surgical guideline "24-12-6" is based on the approximate distance between the anterior lacrimal crest, the anterior and posterior ethmoidal arteries, and the optic canal, commonly used to navigate this area. However, some studies from various populations defined different ratios. Embryologically, the EF were formed by the union of intramembranous ossified frontal bones and endochondral ossified ethmoid bones. EF and neurovascular structures can be identified in computed tomography even in the 3 mm sectional intervals. A comprehensive anatomical understanding of EF will help clinicians improve surgical guidelines and ultimately reduce the risk of complications.