Background: Ethmoidal foramina on the medial orbital wall show a higher incidence of variation. Surgeons performing endonasal, anterior cranial fossa and medial orbital wall surgeries must be aware of these variations as they are a source of hemorrhage and also serve as landmark in proximity to the orbital apex.
Aim: To determine the distances of the ethmoidal foramina from the midpoint of anterior lacrimal crest and optic canal.
Methods: The study was done on 200 adult dry human south Indian skulls. The distance of ethmoidal foramina from anterior lacrimal crest to optic canal was measured with the help of Vernier caliper, probe and magnifying glass.
Results: The study shows that the distances from Anterior Lacrimal Crest (ALC) to Optic Canal (OC) (4.71±0.04 & 4.43±0.04), ALC to Anterior Ethmoidal Foramen (AEF) (2.85±0.03 & 2.59±0.04), OC to Posterior Ethmoidal Foramen (PEF) (1.61±0.03& 1.35±0.03) were almost within the same range on both the sides. Some accessory middle ethmoidal foramina were also reported in between the AEF and PEF on both the sides in some of the dry human skulls.
Conclusion: The results of the study may help the surgeons to ensure the safe and precise performance of medial orbital wall surgeries to avoid injuries to ethmoidal nerves and hemorrhage of ethmoidal arteries.
Keywords: Morphometry, Ethmoidal foramen, Optic canal, Orbital surgery
