Medial microsurgical approach to the orbit: an anatomic study.

The authors have identified and described three medial approaches to the intraorbital portion of the optic nerve in cadavers. The structures exposed via the superior, inferior or central approaches were approached through the medial orbital wall. The superior approach in which the medial rectus muscle is retracted inferiorly exposes the superomedial aspect of the orbit. The inferior approach in which the medial rectus muscle is retracted superiorly, provided the inferomedial aspect of the optic nerve from the globe to the muscle cone. The central approach in which the ethmoidectomy was performed and the medial rectus muscle was disinserted and retracted, provided excellent exposure of the structures of the medial part of the orbit and the optic nerve. There were no structures blocking access to the two third anterior optic nerve and medial surface of the globe. The structures encountered in these approaches are demonstrated under magnification in cadavers, and the exposure of the optic nerve is discussed.