ENT Ear 24a52c08 Surface area of tympanic membrance A 55mm2 B 70mm2 C 80mm2 D 90mm2 High-Yield Explanation The surface area of tympanic membrane is 90 mm2. Only 55 mm2 is functional. Ref: PL Dhingra 6th edition of Ear, Nose and Throat; pg no 14