Ruptured eardrum. The eardrum (tympanic membrane) has a large hole it in at upper right. A yellow trail of the protein keratin runs from the eardrum outwards along the external ear canal to upper right. This arises from an abnormal migratory pattern in the squamous epithelium that lines the ear. The eardrum (tympanic membrane) is a thin membrane that vibrates when sound waves contact it, and a series of small bones transmit the vibrations to the cochlea, where they are converted into nerve impulses that the brain interprets as sound. A severely ruptured eardrum can lead to temporary deafness, and may require surgical correction to repair.