Figure 2

CT PNS coronal section showing the three types of TMS classification; (A) is Type 1 (low risk) where both OF-CP and OF-ER are 10 mm and above, (B) is Type 2 (moderate risk) where either OF-CP or OF-ER is less than 10 mm and (C) is type 3 (high risk) where both OF-CP and OF-ER are less than 10 mm.