A Systematic and Critical Review on the Anatomy of the Ethmoidal Foramina.

Purpose: The osteologic anatomy of the orbit is still a field of intense research, particularly as far as vascular channels are concerned. Among them, ethmoidal foraminas (EFs) are certainly those that have more clinical importance and indeed have been deeply investigated. Unfortunately, the vast production of articles, far from clarifying their anatomy, generated a certain degree of confusion.

Methods: A search on Pubmed and Scopus databases updated up to December 31, 2023, has been carried out with the keyword "ethmoidal foramen" yielding a list of 357 items. With a careful screening process, 31 articles were enlisted to be included in the present review.

Results: A critical review process confirmed that many results published over the years appear inconsistent, particularly as far as EFs topography is concerned. The possible reasons for this lack of consistency can be traced back to inter-ethnical differences, uncertainty on the anterior bony landmarks employed in the investigations, and lack of a general consensus over EFs classification. A novel approach, based on the normalization of the distance of the anterior landmarks relative to the length of the orbit (relative depth index), should overcome some of the major problems encountered so far.

Conclusions: Novel and clear guidelines to classify EFs and to locate them on the medial wall are required. Determining the relative depth index of EFs may be an interesting approach to solve the matter. Other methods can be also devised. However, direct measurements from bony landmarks, without any further analysis seem inadequate and possibly misleading.