The inferior orbital fissure (IOF) is an important structure during orbital surgery, however, neither its anatomical features nor the procedures necessary to expose the IOF have been examined in detail. A morphometric analysis of the IOF was performed on 232 orbits using computer software. The longest and shortest borders of the IOF were 18.2 +/- 4.9 and 1.9 +/- 1.3 mm, respectively. The outer and the inner angles were 138.9 +/- 32.7 degrees and 38.4 +/- 24.7 degrees , respectively. The perimeter of the IOF was 50.6 +/- 13.5 mm and its area was 61.3 +/- 39.1 mm(2). Eight types of IOF were observed. Type 1 IOF was observed in 42.2% and the Type 2 IOF was identified in 15.9%. A statistically significant relation was found between the longest edge and area and the widest edge and area of the IOF. The findings of our study suggest that the removal of the lateral wall should begin inferiorly, just lateral to the IOF and extended superolaterally. These data may be useful during surgical approaches to the orbit.