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Linear measurements of the nasal bones (height and width) and piriform aperture (height, upper and lower widths) were taken from 56 dry adult Anatolian skulls of unknown age and sex. The shape of the nasal bones was classified (types A to E) using the criteria outlined by Hwang et al. A new piriform aperture index (height/lower width) (types I to IV) was calculated defining its shape. The mean height and width of the nasal bones were 19.3 and 12.4 mm, respectively, with type A being observed in 39.3% of skulls, type B in 3.6%, type C in 12.5%, type D in 10.7%, and type E in 33.9%. The mean height, upper and lower widths of the piriform aperture were 36.3, 16.6, and 23.9 mm, respectively, with the shape of piriform aperture being type I in 25.0% of skulls, type II in 51.8%, type III in 10.7%, and type IV in 12.5%. Racial differences are apparent in the proportions of nasal bone types and dimensions of the piriform aperture, which must be taken into account during subcranial, transnasal, and transsphenoidal approaches of surgery for tumors involving the base of the skull.