ABSTRACT
This chapter focuses on the practice of aviation medicine, bearing in mind that all of those involved in aviation are equally susceptible to the same causes of auditory dysfunction as the general population. The internal ear is embedded in the bony labyrinth filled with perilymph, and can be divided into three anatomical and functional regions: the semicircular canals, the vestibule and the cochlea. Within the bony labyrinth lies the membranous labyrinth which is filled with endolymph and contains the sensory cells of both hearing and balance. Pathology affecting the external and middle ear may give rise to abnormalities of the mechanical transmission of sound waves from the environment to the cochlea. Conductive hearing loss is significantly less common than the causes of sensorineural hearing loss in the adult population, but may occur as a consequence of barotrauma with middle ear effusion and, in extremis, with tympanic membrane perforation.
