Chapter 13: Eye and Ear Anatomy

Ophthalmology

The diagnosis and treatment of eye disorders and diseases.

Optometry

Measuring vision and prescribing corrective solutions.

Audiology

The diagnosis, treatment, and prevention of hearing disorders.

Otorhinolaryngology

The medical specialty dealing with ear, nose, and throat disorders.

Ophthalmologist

A specialist who diagnoses and treats eye disorders.

Optometrist

A specialist who measures vision and prescribes corrective solutions.

Audiologist

A specialist who diagnoses and treats hearing disorders.

Otorhinolaryngologist

A medical doctor specializing in ear, nose, and throat disorders.

Meibomian

Sebaceous glands that produce oil to lubricate the eyelashes.

Lacrimal

Relating to tears and tear-producing structures.

Lacrimation

The process of producing tears.

Lacrimal glands

Glands above the eyeballs that produce tears.

Lacrimal sacs

Small sacs that collect tears before they drain into the nose.

Nasolacrimal ducts

Ducts that carry tears from the lacrimal sacs to the nasal cavity.

Extraocular muscles

Muscles attached to the eyeball that move the eyes.

Rectus

Straight muscles that help move the eyes.

Oblique

Diagonal muscles that help move the eyes.

Sclera

The white, outer portion of the eye.

Cornea

The transparent front covering of the eye.

Limbus

The border between the sclera and cornea.

Uvea (choroid, ciliary body, iris)

The middle, vascular layer of the eye.

Iris

The colored part of the eye that controls how much light enters.

Pupil

The dark opening in the center of the iris.

Ciliary body

Muscle tissue that holds the lens and produces aqueous humor.

Lens

A protein structure that focuses light inside the eye.

Aqueous and vitreous humors

Fluids inside the eye; aqueous is watery and vitreous is jellylike.

Retina

The inner layer of the eye containing sensory receptors for vision.

Rods

Retinal receptors responsible for vision in dim light.

Cones

Retinal receptors responsible for color vision.

Macula lutea

The area of the retina where light focuses during daylight.

Fovea

An area within the macula containing only cones and providing the sharpest vision.

Optic disk

The point where the optic nerve leaves the retina, creating a natural blind spot.

Pinna/auricle

The visible, cartilage-covered outer ear.

External auditory canal

The passage that carries sound into the ear.

Cerumen

Earwax that traps debris and protects the ear.

External auditory meatus

The opening of the outer ear.

Tympanic membrane

The eardrum separating the outer and middle ear.

Ossicles/ossicular chain

Three tiny middle-ear bones that transmit sound.

Malleus

The hammer-shaped middle-ear bone.

Incus

The anvil-shaped middle-ear bone.

Stapes

The stirrup-shaped middle-ear bone.

Oval window

The opening where the middle ear meets the inner ear.

Eustachian tube

A tube connecting the middle ear and throat that equalizes pressure.

Inner ear/labyrinth

The inner ear, containing structures for hearing and balance.

Membranous and bony labyrinth

Two sections of the inner ear.

Perilymph and endolymph

Fluids found in the labyrinth of the inner ear.

Vestibule

Part of the inner ear involved in balance.

Utricle

A structure in the vestibule that helps determine static equilibrium.

Saccule

A structure in the vestibule that helps determine static equilibrium.

Semicircular canals

Inner-ear structures that detect movement and rotation.

Crista ampullaris

A structure that detects sudden rotational movement.

Cochlea

The spiral-shaped inner-ear structure responsible for hearing.

Organ of Corti

The structure containing hearing receptor cells.

Vestibulocochlear nerve/eighth cranial nerve

The nerve that carries hearing and balance information to the brain.

Blepharedema

Swelling of the eyelid.

Blepharitis

Inflammation of the eyelid.

Blepharochalasis

Hypertrophy of the eyelid skin.

Blepharoptosis

Drooping of the upper eyelid.

Ectropion

Turning outward of the eyelid.

Entropion

Turning inward of the eyelid.

Chalazion

A hardened swelling caused by a blocked meibomian gland.

Meibomian cyst

Another name for a chalazion.

Hordeolum

An infection of a sebaceous gland of an eyelash.

Stye (sty)

A common name for a hordeolum.

Dacryoadenitis

Inflammation of a lacrimal gland.

Dacryocystitis

Inflammation of a lacrimal sac.

Epiphora

Excessive tearing or overflow of tears.

Xerophthalmia

Dry eyes caused by inadequate tear production.

Conjunctivitis

Inflammation of the conjunctiva, commonly called pinkeye.

Ophthalmia neonatorum

Severe conjunctivitis in a newborn.

Amblyopia

Dull or dim vision due to disuse.

Diplopia

Double vision.

Emmetropia

Normal vision.

Exophthalmia

Protrusion of the eyeball from its orbit.

Strabismus

Lack of coordination between the eyes.

Esotropia

Turning inward of one or both eyes.

Exotropia

Turning outward of one or both eyes.

Photophobia

Extreme sensitivity to light.

Myopia

Nearsightedness; difficulty focusing on distant objects.

Hyperopia

Farsightedness; difficulty focusing on nearby objects.

Astigmatism

Abnormal curvature of the cornea causing blurred vision.

Asthenopia

Weakness or strain of vision.

Presbyopia

Age-related loss of lens elasticity.

Corneal ulcer

An abrasion of the outer covering of the eye.

Keratitis

Inflammation of the cornea.

Anisocoria

Unequal pupil sizes.

Hyphema

Blood in the anterior chamber of the eye.

Uveitis

Inflammation of the uvea.

Aphakia

Absence of the lens.

Cataract

Progressive loss of transparency of the lens.

Glaucoma

Disorders involving abnormal intraocular pressure.

Achromatopsia

Impairment of color vision.

ARMD/AMD

Age-related macular degeneration; progressive damage to the macula.

Diabetic retinopathy

Retinal damage caused by diabetes.

Hemianopsia

Loss of half of the visual field.

Nyctalopia

Inability to see well in dim light.

Retinal tear/retinal detachment

Separation of the retina from the choroid layer.

Retinitis pigmentosa

Hereditary degeneration causing night blindness and progressive visual-field loss.

Scotoma

An area of decreased vision in the visual field.

Nystagmus

Involuntary, rhythmic back-and-forth eye movement.