Morphometric study of the medial orbital wall emphasizing the ethmoidal foramina

Purpose: 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: The present study aims to describe the morphometric distances of various ethmoidal foramina between anterior lacrimal crest to optic canal in south Indian dry human skulls. Materials and method: The study was done on 44 adult dry human skulls. The occurrence of Ethmoidal foramina was noted by direct inspection. The distance of Ethmoidal foramina from anterior lacrimal crest to optic canal was measured with the help of ruler, probe and magnifying glass. Results: The Posterior ethmoidal foramina were found in all 44 skulls bilaterally. Middle ethmoidal foramen was present in 12 and 13 skulls on right and left, respectively. Anterior ethmoidal foramen was found in 38 and 37 skulls on right and left, respectively. The distance between anterior lacrimal crest (ALC) and posterior lacrimal crest (PLC) was in the range of 3–8 mm and that of ALC to anterior ethmoidal foramen was in the range of 24–30 mm. The range of distance between anterior ethmoidal foramen to posterior ethmoidal foramen was 9–17 mm and that between posterior ethmoidal foramen to optic canal was 5–13 mm. Conclusion: These observations would help to predict the anatomical variations in the position of ethmoidal foramina with respect to anterior and posterior lacrimal crest and ensure the safe and precise performance of medial orbital wall surgeries to avoid injuries to the important neurovascular bundles passing through various foramina and fissures.