Orbital apex anatomy: relationship between the optic foramen and anterior face of sphenoid sinus - a radiological study

Background/objectives: This study aims to identify radiologically the position of the optic foramen in relation to the anterior face of the sphenoid sinus, to aid surgeons in their planning for orbital decompression.

Methods: CT scans of 100 orbits from 50 adult patients without any abnormality were assessed. Primary outcome measures included: position and measurement of the distance from the optic foramen to the anterior face of the sphenoid sinus. Secondary outcomes included: medial orbital wall length, distance from the optic foramen and the anterior face of the sphenoid sinus to the carotid prominence in the sphenoid sinus, and the thickness of bone anterior to the optic foramen.

Results: The mean location of the optic foramen was just posterior to the position of the anterior face of sphenoid sinus, with an average distance of +0.4 +/- 3.5 mm. In 54% of orbits the optic foramen was positioned posterior to the anterior face of the sphenoid sinus. The finding was symmetrical in 80% of patients.

Conclusions: Our study identifies that the optic foramen lies posterior to the anterior face of sphenoid sinus in approximately half of cases. The position may be asymmetric in 20% of individuals.