In 2343 sides of crania investigated, 1627 sides of the pterion were studied, if those of epipteric bones being excluded.

• 通常,是以顶骨下角与蝶骨大翼相接额颞二骨分离而形成的,但也有以额、颞二骨相接顶蝶二骨分离而形成翼区的(出现例数甚少);