Chapter 8: Outer and Middle Ear Flashcards
acoustic reflex
a bilateral middle ear muscle contraction in response to a loud sound in one or both ears.
aditus ad antrum
a narrow bony passageway in the posterior bony wall of the middle ear that connects the tympanum to the antrum
annular ligament
a ring-shaped ligament that holds the stapes footplate in the oval window
annulus
a ring-shaped ligament that holds the tympanic membrane in place along its lateral edges.
anterior ligament of the malleus
a ligament that attaches the malleus to the anterior wall of the tympanic cavity.
antihelix
a cartilaginous ridge of the pinna that is medial to and generally parallel to the helix.
antitragus
a small cartilaginous projection of the pinna that is adjacent to the tragus (separated y the internal notch); superior to the ear lobe.
antrum
a small chamber within the mastoid portion of the temporal bone that is posterior to the main middle ear cavity.
auricular tubercle
Darwin’s tubercle
a bump of tissue along the edge of the helix observed in some pinnae.
azimuth estimation
the process of determining the direction in the horizontal plane at which a sound is arriving at the listener.
binaural
related to two ears.
binaural localization cues
localization cues created by differences in the acoustic characteristics of sounds as they arrive at the right ear and left ear
cartilaginous portion of the ear canal
the outer 1/3 of the ear canal formed by a cartilaginous framework
catenary lever (buckling effect)
the anatomic lever created because the Umbo is displaced less than the rest of the tympanic membrane; as a result, the pressure at the Umbo is about two times (6dB) grater that the pressure across the entire membrane.
cave concha
the more inferior of the two parts of the concha; the portion of the concha closest to the external auditory meatus.
cerumen
earwax
chorda tympani
a branch of the facial nerve that crosses the epitympanum from the back to the tympanic cavity to the front just beneath the head of the malleus and incus; joins the lingual nerve to provide taste sensation to the anterior portion of the tongue.
concha
a bowl shaped depression that comprises the deepest groove in the pinna
cone of light
a light reflection off the tympanic membrane seen during otoscopic examination; observed on the anterior inferior quadrant in a normal ear.
crura of the antihelix
the superior portion of the anti helix where it divides to form two folds separated by the triangular fossa.
crus of the helix
the most medial aspect of the helix, which connects the helix to the side of the head and to the conch
cymbal concha
the most superior of the two parts of the concha; the portion of the conch farthest from the external auditory meatus.
(auditory) distance estimation
the process of determining how far one is from a sound source.
elevation estimation
the process of determining the angle between the horizontal plane passing through the ears of a listener and the direct in the vertical plane from which the sound is arriving.
epitympanum
the superior portion of the tympanum
eustachian tube
(auditory tube, pharyngotympanic tube)
the channel that begins on the anterior wall of the middle ear an connects the middle ear cavity with the nasopharyngeal cavity.
external auditory canal
the anatomic tube that begins at the external auditory meatus and extends medially to the tympanic membrane
external auditory meatus
the external opening of the ear canal, located at the medial edge of the pinna
helix
the outer cartilaginous fold of the pinna that curves around the outside edge; it begins at the superior border to the lobule and end at the crus of the helix
hypotympanum
the crest-shaped inferior portion of the middle ear cavity located below the inferior border of the annulus and below the eustachian tube.
incudostapedial joint
the joint formed between the lenticular process of the incus and the head of the stapes.
incus
one of the bones of the inner ear, attached at one end to the malleus ant at the other end to the stapes; known as the anvil in nonprofessional terms.
inner ear
the portion of the ear that contains the vestibular and cochlear sense organs, which are responsible for generating neural impulses in response o mechanical motions; neural impulses generated here are later interpreted by the brain for sound perception and maintenance of balance.
interaural intensity difference (IID)
the difference in intensity of the sound wave arriving to the left ear and right ear.
interaural phase difference (IPD)
the difference in phase of the sound wave arriving to the left ear and right ear
interaural time difference (ITD)
the difference in time of arrival of the sound wave arriving to the left ear and right ear.
intertragal notch
groove between the trigs and the antitragus
isthmus
a narrowing of the ear canal lateral to the tympanic membrane
Lenticular process of the incus
the “L” shaped bend at the end of the long process of the incus.
levator veil palatini muscle
muscle located in the soft tissue lining the nasopharyngeal cavity; contraction of this muscle assists the tensor veil palatine in the opening of the eustachian tube.
lobule (ear lobe)
earlobe; the most inferior portion of the pinna; the portion of the pinna that does not contain cartilage.
localization
the process of determining the direction of incoming sound or the location of a sound source in space in terms of its azimuth and elevation.
localization cues
the specific characteristics of received sounds that are used to determine the direction of incoming sounds.
malleus
one of the bones of the inner ear, attached at one end to the tympanic membrane and the other end to the incus; known as the hammer in nonprofessional terms.
manubrium of the malleus
the most lateral aspect of the mandible which attaches to the tympanic membrane.
mastoid air cells
air pockets that resemble a honeycomb within the mastoid portion of the temporal bone; surround the antrum
mesotympanum
the middle portion of the tympanic cavity
middle ear
the air-filled cavity (about 2cm^3 in volume) called the tympanic cavity or tympanum containing the ossicles.
monaural
related to one ear
monaural location cues
localization cues that are created by the reflection and refraction of sound by the folds, cavities, and ridges of the outer ear.
nasopharyngeal cavity
(nasopharynx)
the paper part of the throat, behind the nasal cavity
notch of Rivinus
a tinny interruption in the tympanic sulcus
obturator foamen
the hole between the crura of the stapes
Osseous portion of the ear canal
the inner 2/3 of the ear canal in which the underlining tissue is bone rather than cartilage.
Ossicles
Ossicular chain
the three bones of the middle ear: the malleus, incus, and stapes.
ossicular lever
the anatomic lever crated due to a difference in the length of the incus; as a result, the force acting at the incus is about 1.15 times (about 1.2 dB) greater than the force action at the malleus
otoscope
an instrument that has a narrow tip, a light, and a magnifying lens; used for examination of the ear canal and tympanic membrane (otoscopic examination)
outer ear
the externally visible portion of the ear, which consists of the pinna and the external auditory canal.
pars flaccida
the superior portion of the tympanic membrane that is relatively loose (flaccid)
pars tensa
the portion of the tympanic membrane that is stretched taut; inferior to and larger than the pars flaccida
pinna (auricle)
the externally visible structure of the outer ear extending out from the side of the head at about a 30 degree angle around the external auditory meatus (opening) of the ear anal.
posterior ligament of the incus
a ligament that attaches the incus to the posterior wall of the tympanic cavity
pressure transformer
the pressure increase that results because of the size difference between the tympanic membrane and oval window; the tympanic membrane is 17 times larger than the oval window and this ratio results in about 17 times (25dB) greater pressure at the oval window than the pressure at the tympanic membrane.
pyramidal eminence
a boney projection of the posterior wall containing a tunnel from which the tendon of the stapedius muscle emerges
scaphoid fossa
a grove underneath the curve of the helix
stapedius muscle
a muscle located within the posterior wall of the tympanic cavity; the stapedius ligament attached to this muscle emerges from the wall of the middle ear and attaches to the neck of the steps bone.
stapes
the most medial and smallest of the middle ear bones/ known as the stirrup in nonprofessional terms
tegmen tympani
the superior wall of the tympanum, a thin plate of bone separating the middle ear from the cranial cavity
temporomandibular joint
the jaw joint; anterior to the ear canal
tensor tympani muscle
the muscle located in the anterior wall of the middle ear; the tendon of the tensor tympani attaches to this muscle and emerges from the wall of the middle ear and attaches to the malleus.
tensor veli palatini muscle
a muscle located in the soft tissue of the nasopharynx, affected to the cartilaginous portion of the eustachian tube, contraction of this muscle opens the cartilaginous portion of the eustachian tube during yawning and swallowing
tragus
a small cartilaginous projection of the pinna that is immediately anterior to the external auditory meatus
transducer
a device that changes energy from one form to another
triangular fossa
a triangle-shaped indentation formed by the crura of the antihelix
tympanic cavity
tympanum
an air-filled cavity of the middle ear containing the ossicles
tympanic membrane
ear drum
a membrane at the medial end of the external auditory canal and forming the lateral wall of the middle ear cavity; vibrations of this membrane change acoustic waves into the mechanic vibrations of the ossicles.
tympanic sulcus
a ring-shaped grove in the temporal bone that is the insertion point for the edges of the tympanic membrane
tympanosclerosis
scaring of the eardrum that appears as white patches
Umbo
the tip of the cone of the tympanic membrane
valsalva maneuver
a procedure that pushes air into the middle ear cavity via the eustachian tube; that procedure involves closing the mouth, pinching the nose, and blowing, which forces the eustachian tube to open and admit air.
