(B) 8th nerve # Causes of conductive deafness:> External ear: Any obstruction in the ear canal, e.g. wax, foreign body, furuncle, acute inflammatory swelling, benign or malignant tumour or atresia of canal.> Middle ear: Perforation of tympanic membrane, traumatic or infective; Fluid in the middle ear, E.g. acute otitis media, serous otitis media or haemotympanum Mass in middle ear, E.g. benign or malignant tumour. Disruption of ossicles, E.g. trauma to ossicular chain, chronic suppurative otitis media, cholesteatoma. Fixation of ossicles, E.g. otosclerosis, tympanosclerosis, adhesive otitis media. Eustachian tube blockage, e.g. retracted tympanic membranae serous otitis media. Serous otitis media is the most common cause of conductive deafness in children.