CHL occurs when sound waves cannot transfer through outer, middle or inner ear. Mixed hearing loss occurs when CHL coexists with sensorineural loss. Hearing loss makes sounds faint or muffled, worse in lower frequencies
Eardrum part lies deeper than normal in ear. Affects one quarter of British school children. More common in children with cleft palate
Mastoidectomy removes bony partitions between air cells in skull's mastoid bone. Mastoid bone contains air-filled cavities resembling English muffin. Disease can occur from cholesteatoma or middle ear infection spreading
Stapedius muscle is the smallest skeletal muscle in the body. Located in middle ear's tympanic cavity, extending from stapes bone. Muscle measures between 9-11 millimeters in length. Supplied by posterior auricular and external carotid arteries
Middle ear located after outer ear canal, separated by eardrum. Tympanic cavity is air-filled chamber within petrous part of temporal bone. Three smallest bones (ossicles) transmit sound vibrations to inner ear
Persistent inflammation of middle ear or mastoid cavity. Causes recurrent ear discharge through tympanic membrane perforation. Usually occurs as complication of persistent acute otitis media. Can lead to thickened middle ear mucosa and mucosal polyps