8.10 Glossary

Acute otitis media: The medical diagnosis for a middle ear infection.

Auricle: The large, fleshy structure of the ear on the lateral aspect of the head.

Cerumen impaction: A buildup of earwax causing occlusion of the ear canal.

Conductive hearing loss: Hearing loss that occurs when something in the external or middle ear is obstructing the transmission of sound.

Conjunctiva: Inner surface of the eyelid.

Conjunctivitis: A viral or bacterial infection in the eye causing swelling and redness in the conjunctiva and sclera.

Cornea: The transparent front part of the eye that covers the iris, pupil, and anterior chamber.

Eustachian tube: The tube connecting the middle ear to the pharynx that helps equilibrate air pressure across the tympanic membrane.

Extraocular muscles: Six muscles that control the movement of the eye within the orbit. Extraocular muscles are innervated by three cranial nerves, the abducens nerve, the trochlear nerve, and the oculomotor nerve.

Iris: Colored part of the eye.

Lacrimal duct: Tears produced by the lacrimal gland flow through this duct to the medial corner of the eye.

Lens: An inner part of the eye that helps the eye focus.

Myopia: Impaired vision, also known as nearsightedness, that makes far-away objects look blurry.

Optic nerve: Cranial nerve II that conducts visual information from the retina to the brain.

Otitis externa: The medical diagnosis for external ear inflammation and/or infection.

Ototoxic medications: Medications that cause the adverse effect of sensorineural hearing loss by affecting the hair cells in the cochlea.

Presbycusis: Sensorineural hearing loss that occurs with aging due to gradual nerve degeneration.

Presbyopia: Impaired near vision that commonly occurs in middle-aged and older adults.

Pupil: The hole at the center of the eye that allows light to enter.

Retina: The nervous tissue and photoreceptors in the eye that initially process visual stimuli.

Sclera: White area of the eye.

Sensorineural hearing loss: Hearing loss caused by pathology of the inner ear, cranial nerve VIII, or auditory areas of the cerebral cortex.

Snellen chart: A chart used to test far vision.

Tinnitus: Ringing, buzzing, roaring, hissing, or whistling sound in the ears.

Tympanic membrane: The membrane at the end of the external ear canal, commonly called the eardrum, that vibrates after it is struck by sound waves.

Vertigo: A type of dizziness often described by patients as “the room feels as if it is spinning.”

Vestibulocochlear nerve: Cranial nerve VIII that transports neural signals from the cochlea and the vestibule to the brain stem regarding hearing and balance.