EARS

Ear

Ear

An organ of balance and hearing.

Outer Ear

also known as the auricle or pinna, is responsible for collecting sound waves and guiding them into the ear canal. It consists of the helix, antihelix, and tragus.

Pinna (Auricle)

The fleshy appendage attached to the side of the skull that catches and directs soundwaves to the middle ear.

External Auditory Meatus (Ear Canal)

The ear canal connects the outer ear to the middle ear and transmits sound waves. It has specialized cells and earwax to protect against dust, debris, and infection.

Scapha

large flap concave internal side of the auricle

Helix

entire free margin of the auricle

Antihelix

transverse fold of cartilage on the concave surface of the pinna

Tragus

thick, blunt, irregularly quadrangular plate of cartilage from the rostral border of entrance to the external auditory meatus

Antitragus

thin elongated projection of cartilage

Intertragic Incisure Notch

separates the tragus and antitragus

Middle Ear

The part inside the tympanic cavity containing the auditory ossicles and opening to the auditory tube.

Tympanic Membrane (Eardrum)

A thin semitransparent partition between the external auditory meatus and the middle ear.

Auditory Ossicles

Three bones (malleus, incus, and stapes) that transmit and amplify vibrations from the eardrum to the oval window.

Malleus (Hammer)

connects the inner surface of the ear drum and the incus

Incus (Anvil)

between the malleus and stapes

Stapes

smallest bone of the body; its base fits into the oval window

Vestibular Window

Oval Window; One of the two openings between the middle and internal ear that is filled by the base of the stapes.

Cochlear Window

Round Window; other opening located below the oval window and covered by a secondary tympanic membrane that bulges outward with fluid movement

Eustachian Tube (Auditory Tube)

A passageway between the middle ear and nasopharynx that equalizes the pressure in both sides of the eardrum.

Inner Ear

The part of the ear that includes the cochlea and the vestibular system.

Cochlea

A snail shell-like structure associated with hearing.

Scala Vestibuli

bony labyrinth; superior communicating with the vestibule, middle ear at the oval window, and the scala tympani at the apex of the cochlea

Scala Tympani

bony labyrinth; more inferior, continuation of the scala vestibuli from the apex of the cochlea to the round window

Saccule and Utricle

2 sacs of the membranous labyrinth

Maculae

static equilibrium receptors located perpendicular to each other in the utricle and saccule

Ampulla

a dilatation located at one end of the semicircular canal

Crista

receptor organ found in the ampulla of each semicircular duct, composed of hair (receptor) cells and supporting cells

Endolymph

The fluid within the semicircular canals that moves when the head moves.

Cupula

A gelatinous mass covering the crista in the semicircular canals.

Bony labyrinth

A series of bony cavities within the petrous part of the temporal bone, consisting of the cochlea, vestibule, and three semi-circular canals.

Membranous labyrinth

The inner part of the bony labyrinth, consisting of the cochlear duct, semi-circular ducts, utricle, and saccule.

Periosteum

The lining of the structures within the bony labyrinth.

Perilymph

The fluid contained within the bony labyrinth.

Vestibule

A part of the bony labyrinth involved in balance and spatial orientation.

Semi-circular canals

Three canals within the bony labyrinth that help with detecting rotational movements.