Methods : The observations were made on 93 sides of dry skulls or temporal bones . The mastoid foramina and canals in the mastoid part were measured statistically for their presence 、 locstion 、 diameter and length with the vernier calliper .

方法：采用游标卡尺等测量、统计93侧干性颅（ 颞）骨乳突孔及乳突管（道）的出现率、位置、 内径和长度。