The Surgical Relevance of a Histological Investigation into the Accessory Ethmoidal Foramina and their Contents in a Caucasian Population

Aims: It is the objective of this article to investigate the accessory ethmoidal foramina, located in the medial wall of the orbit, adjacent to the anterior and posterior ethmoidal foramina. Previous studies have shown that there is significant variation in the number and location of the fronto-ethmoidal foramina, causing potential complications during surgery. This study aims to identify accessory foramina in cadaveric orbits, and, using histological staining, further identify any structures passing through the foramina. Methods: Thirty cadaveric orbits from Caucasians were dissected. The number and locations of the accessory foramina in the medial wall were noted. All orbits containing accessory foramina in the medial wall were stained with Sudan black dye, micro-dissected, and microscopically analysed. Results: Accessory foramina were found in twelve orbits. All accessory foramina showed evidence of vasculature. Three orbits had less than five accessory foramina, four orbits presented with five accessory foramina, six accessory foramina presented in four cases, and in one case eight accessory foramina were present. Underdocumented vasculature was found traversing these foramina. Conclusion: This study highlights the occurrence and variations of accessory ethmoidal foramina in a Caucasian population, and presents their vascular contents. Ophthalmic and ENT surgeons operating on, or in proximity to, the medial wall must be aware of these communicating blood vessels when operating on Caucasian patients. This aims to reduce the risk of intra-operative or post-operative complications, especially in anti-coagulated patients or those with bleeding disorders.