A cadaveric study investigating the anatomy of the medial orbital wall

The purpose of this study is to investigate the applicability of the current surgical guideline, known as ‘24-12-6’ surgical guideline, in the Hispanic and European populations. This guideline is used during numerous orbital surgeries and states that the distance between the anterior lacrimal crest to the anterior ethmoidal foramen (24mm), the anterior ethmoidal foramen to the posterior ethmoidal foramen (12mm), and the posterior ethmoidal foramen to the optic canal (6mm) follows a Rule of Halves. Previous studies suggest this surgical guideline varies between ethnicities; however, no data has been published regarding the accuracy of this guideline pertaining to the Hispanic population. An experimental study was performed on 79 cadaver orbits.The important boney landmarks were identified and the distance between each landmark was recorded using a digital caliper. For all cadavers studied, the distances between the anterior lacrimal crest, anterior ethmoidal foramen, posterior ethmoidal foramen, and optic canal were 26.76mm, 13.89mm, and 7.61mm, respectively. Thus, the ‘24-12-6’ surgical guideline was not applicable to the sample studied; these relationships were also not true for the European or the Hispanic populations.Therefore, significant anatomical variations exist in the current surgical guideline along the medial orbital wall. Clinicians may need to adjust their methodology during surgical procedures in order to optimize patient care.