The Anatomy and Pathology of the Ear and Mastoid Processes

A comprehensive set of vocabulary flashcards based on lecture notes regarding the anatomy, physiology, disorders, and clinical treatments of the ear and mastoid process.

external auditory meatus

Also known as the External Auditory Canal (EAC), it is a channel within the temporal bone that directs sound waves to the middle ear.

cerumen

Commonly known as earwax, it is secreted by ceruminous glands to provide defense, maintenance, and a barrier against bacteria, fungi, and insects.

Pars Flaccida

A small, triangular, floppy portion of the tympanic membrane that serves as an anchor point.

Pars Tensa

The main, tightly stretched portion of the tympanic membrane responsible for transmitting sound waves further into the ear.

auditory ossicles

A chain of three tiny bones (malleus, incus, and stapes) in the middle ear that concentrate vibrations for increased sound discrimination.

Malleus

Also called the hammer, this bone's "foot" sits directly on the tympanic membrane.

Incus

Also known as the anvil, this is the middle bridge bone of the ossicular chain.

Stapes

Also known as the stirrup or stay-peas, it is the smallest bone in the human body and sits against the oval window.

Eustachian Tube

A tube linking the middle ear with the nasopharynx that acts as a pressure valve to equalize air pressure on both sides of the tympanic membrane.

mastoid cells

A honeycomb network of small air spaces inside the mastoid process that reduce skull weight and act as voice resonators.

Cochlea

The hearing mechanism of the inner ear that converts mechanical sound waves into electrical impulses.

Organ of Corti

A collection of microscopic hair cells (cilia) that translate fluid movement within the inner ear into electrical signals.

semicircular canals

Three canals arranged orthogonally to track rotational movement in all $3D$ dimensions for balance.

otolithic organs

Two organs per ear designed to detect linear acceleration and changes in velocity.

anacusis

Complete loss of sound perception.

diplacusis

A symptom of hearing the same absolute pitch at different relative pitches in each ear.

hyperacusis

Over-sensitivity to sound within a specific frequency range.

otalgia

Severe earache occurring with no known cause.

otopyorrhoea

The flow of pus from the ear, often a symptom of suppurative otitis media.

otorrhagia

Bloody discharge from the ear.

presbycusis

Impaired hearing caused by the ageing process.

tinnitus

The sensation of noise in the ears, such as ringing or buzzing, when no actual external sound is present.

vertigo

Dizziness described as a sensation of rotation or movement of oneself or the surroundings.

Keratitis obturans

A cholesteatoma that has pushed through the tympanic membrane into the external auditory canal.

Otitis externa

Inflammation of the external ear, noted as the most common disease of the external ear.

Glue Ear

The third stage of ear effusion where the fluid has completely thickened and become mucinous.

mastoiditis

Inflammation of the mucosal lining of the mastoid air system, most common in children aged $2$ to $13$ months.

acoustic neuroma

A benign but life-threatening tumor arising from Schwann cells, usually of the vestibular division of the $8^{th}$ cranial nerve; also called vestibular schwannoma.

otosclerosis

Bony growth of the cochlea, commonly occurring at the oval window, which can fix the stapes in position and impede sound transmission.

conductive hearing loss

A hearing problem caused by sound waves being unable to reach the inner ear.

sensorineural hearing loss

A problem with the conversion of sound waves to electrical impulses or the conveyance of those impulses to the brain.

otoscopy

A visual examination of the ear that typically shows an upside-down image of the tympanic membrane.

Rinne test

A tuning fork test that compares bone conduction at the mastoid bone to air conduction at the auditory meatus.

Weber test

A test where a tuning fork is placed on the center of the forehead to determine if sound loudness is equal in both ears.

myringoplasty

An ear reconstruction procedure that deals only with the tympanic membrane.

tympanoplasty

A surgical procedure involving the reconstruction of both the tympanic membrane and the ossicular chain.

stapedotomy

The preferred modern alternative to a stapedectomy, involving drilling a hole in the fixed part of the stapes to insert a piston prosthesis.

BAHA

Bone Anchored Hearing Aid; a magnetic titanium implant placed in the mastoid process to transmit sound waves to the cochlea via bone.