Because the depth of our ear canal is mostly 2.5-3 cm, the bottom of the ear canal is the paper-thin eardrum. Using a 3 cm sharp instrument to pull out the ear, especially in the presence of someone, can easily cause the eardrum to rupture, which is a very common cause of eardrum rupture. This is a very common cause of eardrum rupture because others can easily inadvertently touch the person taking out the ear, causing the sharp object to penetrate deep into the ear canal and pierce the eardrum.