An anatomical study of the positional relationship between the ethmoidal foramina and the frontoethmoidal suture.

Purpose: To examine the positional relationship between the ethmoidal foramina and the frontoethmoidal suture.

Methods: Eighty-four orbits of 42 Japanese cadavers (24 male and 18 female cadavers; average age at death, 81.0 years; range, 61-101 years), fixed in 10% buffered formalin, were used for investigation. The most anterior or posterior ethmoidal foramen was defined as the anterior or posterior ethmoidal foramen, respectively. All the intermediate foramina were determined as the accessory foramina. The vertical distances from the frontoethmoidal suture to the anterior, posterior, and accessory ethmoidal foramina were examined.

Results: Seventeen anterior ethmoidal foramina (20.2%) were situated above the frontoethmoidal suture (mean distance, 1.8 mm), and 2 posterior ethmoidal foramina (2.3%) were situated at 1.0 mm and 1.5 mm above the suture. Although accessory ethmoidal foramina were detected in 32 orbits (38.1%), one accessory foramen (middle ethmoidal foramen) was identified in 30 orbits, and 2 foramina (additional deep-middle ethmoidal foramina), in 2 orbits. One middle ethmoidal foramen (3.1%) and 1 deep-middle ethmoidal foramen (50.0%) were located at 1.5 mm above the suture. In total, 2 of the 34 accessory ethmoidal foramina (5.9%) exhibited the extrasutural location.

Conclusions: Several ethmoidal foramina were situated above the frontoethmoidal suture. The anterior ethmoidal foramen most frequently showed the situation, followed by the accessory and posterior foramina, in order. Our findings help predict the anatomical variations in the location of the ethmoidal foramina in relation to the frontoethmoidal suture, thereby enhancing safety for medial orbital wall surgery.