Tympanic membrane retraction become eroded. As skin cells die they form a barrier of dry protein called keratin. This layer of keratin is normally pushed out of the ear by migration of skin cells along the ear canal and is turned into wax. Clearance of keratin can be disrupted by tympanic membrane retraction so that keratin accumulates within the retraction pocket. When keratin becomes trapped deep inside the ear and cannot be cleaned out, it is known as cholesteatoma. Growth of bacteria in the trapped keratin causes smelly discharge from the ear and can spread to cause serious infection. Various strategies may be
Common name nomenclature is a global system that attempts to denote particular organisms or taxa uniquely and , on the assumption that such organisms or taxa are well-defined and generally also have well-defined interrelationships; accordingly the ICZN has formal rules for biological nomenclature and convenes periodic international meetings to further that purpose. The form of scientific names for organisms that are called binomial nomenclature is superficially similar to the noun-adjective form of vernacular names or common names which were used by prehistoric cultures. A collective name such as "owl" was made more precise by the addition of an adjective such as "screech".