The superior orbital fissure and its contents.

Topographic landmarks for the superior orbital fissure are useful for general orientation and approach to the middle fossa, cavernous sinus and orbit. In this study, the microsurgical anatomy and morphometry of the superior orbital fissure and its related structures were examined in 57 disarticulated sphenoid bones, 102 skull bases and 58 adult cadaveric heads. The superior orbital fissure was observed in nine different shapes based on the classification of Sharma et al. (1988), and the most frequently observed was Type VI. The distance from the superomedial to the superolateral edge was measured as 17.3 +/- 3.4 mm on the right side and 16.9 +/- 2.9 mm on the left side, and from the superolateral to the inferior edge as 20.8 +/- 3.9 mm on the right side and 20.1 +/- 3.8 mm on the left side. The distance from the superomedial to the inferior edge of the fissure was measured as 9.5 +/- 2.2 mm on the right side and 9 +/- 2.4 mm on the left side. No right-left differences were observed for these measurements. Measurements regarding the relationship of the oculomotor, trochlear and abducent nerves, the ophthalmic branch of the trigeminal nerve and the superior orbital vein were performed and topographic aspects of the superior orbital fissure region were described.