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In the
anatomy Anatomy (Greek ''anatomē'', 'dissection') is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science which deals with the structural organization of living things. It ...

anatomy
of humans and various other
tetrapod Tetrapods (; ) are four-limbed animals constituting the superclass Tetrapoda (). It includes extant Extant is the opposite of the word extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a sp ...
s, the eardrum, also called the tympanic membrane or myringa, is a thin, cone-shaped
membrane A membrane is a selective barrier; it allows some things to pass through but stops others. Such things may be molecules, ions, or other small particles. Biological membranes include cell membranes (outer coverings of cells or organelles that all ...
that separates the
external ear The outer ear, external ear, or auris externa is the external part of the ear The ear is the organ of hearing and, in mammals, balance. In mammals, the ear is usually described as having three parts—the outer ear The out ...
from the
middle ear The middle ear is the portion of the ear The ear is the organ of hearing and, in mammals, balance. In mammals, the ear is usually described as having three parts—the outer ear The outer ear, external ear, or auris externa is th ...

middle ear
. Its function is to transmit
sound In physics Physics is the that studies , its , its and behavior through , and the related entities of and . "Physical science is that department of knowledge which relates to the order of nature, or, in other words, to the regular ...

sound
from the air to the
ossicles The ossicles (also called auditory ossicles) are three bone A bone is a rigid tissue Tissue may refer to: Biology * Tissue (biology), an ensemble of similar cells that together carry out a specific function * ''Triphosa haesitata'', a spe ...
inside the middle ear, and then to the
oval window The oval window (or ''fenestra vestibuli'' or ''fenestra ovalis'') is a membrane-covered opening from the middle ear to the cochlea The cochlea is the part of the inner ear involved in hearing. It is a spiral-shaped cavity in the bony labyrinth, ...
in the fluid-filled
cochlea The cochlea is the part of the inner ear involved in hearing. It is a spiral-shaped cavity in the bony labyrinth, in humans making 2.75 turns around its axis, the modiolus (cochlea), modiolus. A core component of the cochlea is the Organ of Cort ...

cochlea
. Hence, it ultimately converts and amplifies vibration in air to vibration in cochlear fluid. The
malleus The malleus, or hammer, is a hammer-shaped small bone or ossicle The ossicles (also called auditory ossicles) are three bone A bone is a Stiffness, rigid tissue (anatomy), tissue that constitutes part of the vertebrate skeleton in animals. ...

malleus
bone bridges the gap between the eardrum and the other ossicles. Rupture or perforation of the eardrum can lead to
conductive hearing loss Conductive hearing loss (CHL) occurs when there is a problem transferring sound wave In physics Physics (from grc, φυσική (ἐπιστήμη), physikḗ (epistḗmē), knowledge of nature, from ''phýsis'' 'nature'), , is th ...
. Collapse or
retraction In academic publishing, a retraction is the action by which a published paper in an academic journal is removed from the journal. Online journals typically remove the retracted article from online access. Procedure A retraction may be initiate ...
of the eardrum can cause conductive hearing loss or
cholesteatoma Cholesteatoma is a destructive and expanding growth consisting of keratinizing squamous epithelium in the middle ear and/or mastoid process. Cholesteatomas are not cancerous as the name may suggest, but can cause significant problems because of th ...
.


Structure


Orientation and relations

The tympanic membrane is oriented obliquely in the
anteroposterior Standard anatomical terms of location deal unambiguously with the anatomy Anatomy (Greek ''anatomē'', 'dissection') is the branch of biology concerned with the study of the structure of organism In biology, an organism (from Ancient ...
, mediolateral, and superoinferior planes. Consequently, its superoposterior end lies lateral to its anteroinferior end. Anatomically, it relates superiorly to the
middle cranial fossa The middle cranial fossa, deeper than the anterior cranial fossa, is narrow medially and widens laterally to the sides of the skull The skull is a bone A bone is a Stiffness, rigid tissue (anatomy), tissue that constitutes part of the vert ...
, posteriorly to the
ossicle The ossicles (also called auditory ossicles) are three bone A bone is a Stiffness, rigid tissue (anatomy), tissue that constitutes part of the vertebrate skeleton in animals. Bones protect the various organs of the body, produce red blood cel ...
s and
facial nerve The facial nerve (the labyrinthine segment) is the seventh Cranial nerves, cranial nerve, or simply CN VII. It emerges from the pons of the brainstem, controls the muscles of facial expression, and functions in the conveyance of taste sensation ...

facial nerve
, inferiorly to the
parotid gland The parotid gland is a major salivary gland The salivary glands in mammals are exocrine glands that produce saliva through a system of Duct (anatomy), ducts. Humans have three paired major salivary glands (Parotid gland, parotid, Submandibular ...
, and anteriorly to the
temporomandibular joint In anatomy Anatomy (Greek ''anatomē'', 'dissection') is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science which deals with the structural organization of ...

temporomandibular joint
.


Regions

The eardrum is divided into two general regions: the pars flaccida and the
pars tensa In the anatomy of humans and various other tetrapods, the eardrum, also called the tympanic membrane or myringa, is a thin, cone-shaped biological membrane, membrane that separates the external ear from the middle ear. Its function is to transmit ...
. The relatively fragile pars flaccida lies above the lateral
process A process is a series or set of activities that interact to produce a result; it may occur once-only or be recurrent or periodic. Things called a process include: Business and management *Business process A business process, business method ...
of the
malleus The malleus, or hammer, is a hammer-shaped small bone or ossicle The ossicles (also called auditory ossicles) are three bone A bone is a Stiffness, rigid tissue (anatomy), tissue that constitutes part of the vertebrate skeleton in animals. ...

malleus
between the notch of Rivinus and the anterior and posterior malleal folds. Consisting of two layers and appearing slightly pinkish in hue, it is associated with
Eustachian tube In anatomy Anatomy (Greek ''anatomē'', 'dissection') is the branch of biology Biology is the natural science that studies life and living organisms, including their anatomy, physical structure, Biochemistry, chemical processes, Mole ...
dysfunction and
cholesteatoma Cholesteatoma is a destructive and expanding growth consisting of keratinizing squamous epithelium in the middle ear and/or mastoid process. Cholesteatomas are not cancerous as the name may suggest, but can cause significant problems because of th ...
s. The larger pars tensa consists of three layers:
skin Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other cuticle, animal coverings, such as the arthropod exoskeleton, have differ ...

skin
,
fibrous tissue Fiber or fibre (from la, fibra, links=no) is a natural Nature, in the broadest sense, is the natural, physical, material world or universe The universe ( la, universus) is all of space and time and their contents, including ...
, and
mucosa A mucous membrane or mucosa is a membrane A membrane is a selective barrier; it allows some things to pass through but stops others. Such things may be molecules, ions, or other small particles. Biological membranes include cell membranes (ou ...

mucosa
. Its thick periphery forms a fibrocartilaginous ring called the
annulus tympanicus Annulus (or anulus) or annular may refer to: Human anatomy * ''Anulus fibrosus disci intervertebralis An intervertebral disc (or intervertebral fibrocartilage) lies between adjacent vertebrae in the vertebral column The vertebral column, a ...
or Gerlach's ligament. while the central umbo tents inward at the level of the tip of malleus. The middle fibrous layer, containing radial, circular, and parabolic fibers, encloses the handle of malleus. Though comparatively robust, the pars tensa is the region more commonly associated with perforations.


Umbo

The manubrium ( la, handle) of the
malleus The malleus, or hammer, is a hammer-shaped small bone or ossicle The ossicles (also called auditory ossicles) are three bone A bone is a Stiffness, rigid tissue (anatomy), tissue that constitutes part of the vertebrate skeleton in animals. ...

malleus
is firmly attached to the medial surface of the membrane as far as its center, drawing it toward the
tympanic cavity The tympanic cavity is a small cavity surrounding the bones of the middle ear The middle ear is the portion of the ear The ear is the organ of hearing and, in mammals, balance. In mammals, the ear is usually described as having three ...
. The lateral surface of the membrane is thus concave. The most depressed aspect of this concavity is termed the umbo ( la,
shield boss A shield boss, or umbo, is a round, convex Convex means curving outwards like a sphere, and is the opposite of concave. Convex or convexity may refer to: Science and technology * Convex lens A lens is a transmissive optics, optical device ...
).


Nerve supply

Sensation of the outer surface of the tympanic membrane is supplied mainly by the
auriculotemporal nerve The auriculotemporal nerve is a branch of the mandibular nerve The mandibular nerve (V3) is the largest of the three divisions of the trigeminal nerve, the fifth cranial nerve (CN V). Structure The large sensory root emerges from the lateral par ...
, a branch of the
mandibular nerve The mandibular nerve (V3) is the largest of the three divisions of the trigeminal nerve, the fifth cranial nerve (CN V). Structure The large sensory root emerges from the lateral part of the trigeminal ganglion and exits the cranial cavity through ...

mandibular nerve
(
cranial nerve Cranial nerves are the nerve A nerve is an enclosed, cable-like bundle of fibers (called axon An axon (from Greek ἄξων ''áxōn'', axis), or nerve fiber (or nerve fibre: see American and British English spelling differences#-re, -er, ...
V3
V<sub>3</sub>
), with contributions from the auricular branch of the vagus nerve (
cranial nerve X The vagus nerve, historically cited as the pneumogastric nerve, is the tenth cranial nerve or CN X, and interfaces with the parasympathetic control of the heart, lungs, and digestive tract. The vagus nerves are normally referred to in the singular ...
), the
facial nerve The facial nerve (the labyrinthine segment) is the seventh Cranial nerves, cranial nerve, or simply CN VII. It emerges from the pons of the brainstem, controls the muscles of facial expression, and functions in the conveyance of taste sensation ...

facial nerve
(cranial nerve VII), and possibly the
glossopharyngeal nerve The glossopharyngeal nerve (), known as the ninth cranial nerve Cranial nerves are the nerve A nerve is an enclosed, cable-like bundle of nerve fibers called axon An axon (from Greek ἄξων ''áxōn'', axis), or nerve fiber (or nerv ...
(cranial nerve IX). The inner surface of the tympanic membrane is innervated by the glossopharyngeal nerve.


Clinical significance


Examination

When the eardrum is illuminated during a
medical examination In a physical examination, medical examination, or clinical examination, a medical practitioner examines a patient A patient is any recipient of health care Health care, health-care, or healthcare is the maintenance or improvement of health v ...
, a cone of light radiates from the tip of the malleus to the periphery in the anteroinferior quadrant, this is what is known clinically as 5 o'clock.


Rupture

Unintentional
perforation A perforation is a small hole in a thin material or web. There is usually more than one perforation in an organized fashion, where all of the holes collectively are called a ''perforation''. The process of creating perforations is called perfor ...
(rupture) has been described in blast injuries and
air travel Air travel is a form of travel Travel is the movement of people between distant geographical location In geography Geography (from Greek: , ''geographia'', literally "earth description") is a field of science devoted to the ...
, typically in patients experiencing upper respiratory congestion that prevents equalization of pressure in the middle ear. It is also known to occur in
swimming Swimming is the self-propulsion of a person through water, or other liquid, usually for recreation, sport, exercise, or survival. Locomotion is achieved through coordinated movement of the limbs and the body to achieve hydrodynamic thrust whic ...

swimming
,
diving Diving usually refers to: * Diving (sport), the sport of jumping into deep water * Underwater diving, human activity underwater for recreational or occupational purposes Diving or Dive may also refer to: Sports * Dive (American football), a typ ...
(including
scuba diving Scuba diving is a type of underwater diving Underwater diving, as a human activity, is the practice of descending below the water's surface to interact with the environment. Immersion in water and exposure to high ambient pressure have ...

scuba diving
), and
martial arts Martial arts are codified systems and traditions of combat practiced for a number of reasons such as self-defense; military and law enforcement applications; combat sport, competition; physical, mental, and spiritual development; entertainment; an ...
. Patients suffering from tympanic membrane rupture may experience bleeding,
tinnitus Tinnitus is the perception of sound when no corresponding external sound is present. Nearly everyone will experience a faint "normal tinnitus" in a completely quiet room but it is only of concern if it is bothersome or interferes with normal h ...

tinnitus
,
hearing loss Hearing loss is a partial or total inability to hear Hearing, or auditory perception, is the ability to perceive Sound, sounds by detecting Vibration, vibrations, changes in the pressure of the surrounding medium through time, through a ...
, or disequilibrium (
vertigo Vertigo is a condition where a person has the sensation of movement or of surrounding objects moving when they are not. Often it feels like a spinning or swaying movement. This may be associated with nausea Nausea is a diffuse sensation of ...

vertigo
). However, they rarely require medical intervention, as between 80 and 95 percent of ruptures recover completely within two to four weeks. The prognosis becomes more guarded as the force of injury increases.


Surgical puncture for treatment of middle ear infections

The pressure of fluid in an infected middle ear onto the eardrum may cause it to rupture. Usually, this consists of a small hole (perforation), which allows fluid to drain out. If this does not occur naturally, a
myringotomy A myringotomy is a surgical procedure in which an incision is created in the eardrum In the anatomy Anatomy (Greek ''anatomē'', 'dissection') is the branch of biology concerned with the study of the structure of organism In biolo ...
(tympanotomy, tympanostomy) can be performed. A myringotomy is a
surgical Surgery ''cheirourgikē'' (composed of χείρ, "hand", and ἔργον, "work"), via la, chirurgiae, meaning "hand work". is a medical or dental specialty that uses operative manual and instrumental techniques on a person to investigate or t ...
procedure in which a tiny incision is created in the eardrum to relieve pressure caused by excessive buildup of fluid, or to drain
pus Pus is an exudate An exudate is a fluid emitted by an organism through pores or a wound, a process known as exuding or exudation. ''Exudate'' is derived from ''exude'', "to ooze", from the Latin Latin (, or , ) is a classical lang ...

pus
from the
middle ear The middle ear is the portion of the ear The ear is the organ of hearing and, in mammals, balance. In mammals, the ear is usually described as having three parts—the outer ear The outer ear, external ear, or auris externa is th ...

middle ear
. The fluid or pus comes from a middle ear infection (
otitis media Otitis media is a group of inflammatory Inflammatory may refer to: * Inflammation, a biological response to harmful stimuli * The word ''inflammatory'' is also used to refer literally to fire and flammability, and figuratively in relation to com ...
), which is a common problem in children. A
tympanostomy tube Tympanostomy tube, also known as a grommet or myringotomy tube, is a small tube inserted into the eardrum In the anatomy Anatomy (Greek ''anatomē'', 'dissection') is the branch of biology Biology is the natural science that studie ...

tympanostomy tube
is inserted into the eardrum to keep the middle ear aerated for a prolonged time and to prevent reaccumulation of fluid. Without the insertion of a tube, the incision usually heals spontaneously in two to three weeks. Depending on the type, the tube is either naturally extruded in 6 to 12 months or removed during a minor procedure. Those requiring myringotomy usually have an obstructed or dysfunctional
eustachian tube In anatomy Anatomy (Greek ''anatomē'', 'dissection') is the branch of biology Biology is the natural science that studies life and living organisms, including their anatomy, physical structure, Biochemistry, chemical processes, Mole ...
that is unable to perform drainage or ventilation in its usual fashion. Before the invention of antibiotics, myringotomy without tube placement was also used as a major treatment of severe acute otitis media. In some cases, the pressure of fluid in an infected middle ear is great enough to cause the eardrum to rupture naturally. Usually, this consists of a small hole (perforation), from which fluid can drain.


Society and culture

The
Bajau The Sama-Bajau refers to several Austronesian ethnic group An ethnic group or ethnicity is a grouping of people who identify with each other on the basis of shared attributes that distinguish them from other groups such as a common set of ...
people of the
Pacific The Pacific Ocean is the largest and deepest of Earth Earth is the third planet from the Sun and the only astronomical object known to harbour and support life. 29.2% of Earth's surface is land consisting of continents and islands. ...

Pacific
intentionally rupture their eardrums at an early age to facilitate diving and hunting at sea. Many older Bajau therefore have difficulties hearing.


See also

*
Middle ear The middle ear is the portion of the ear The ear is the organ of hearing and, in mammals, balance. In mammals, the ear is usually described as having three parts—the outer ear The outer ear, external ear, or auris externa is t ...

Middle ear
*
Valsalva maneuver The Valsalva maneuver is performed by moderately forceful attempted exhalation Exhalation (or expiration) is the flow of the breath upright=1.4, X-ray video of a female American alligator while breathing. Breathing (or ventilation) is ...

Valsalva maneuver
to equalize pressure across the eardrum


Additional images

File:Anatomy of the Human Ear en.svg, Anatomy of the human right ear. File:Gray907.png, External and middle ear, right side, opened from the front (coronal section) File:Gray908.png, Horizontal section through left ear; upper half of section File:Gray912.png, The right membrana tympani with the hammer and the chorda tympani, viewed from within, from behind, and from above File:Gray915.png, Auditory tube, laid open by a cut in its long axis File:Gray919.png, Chain of ossicles and their ligaments, seen from the front in a vertical, transverse section of the tympanum ympanic cavityFile:Gray909.png, Right eardrum as seen through a speculum File:Normal Left Tympanic Membrane.jpg, This is a normal left eardrum. File:Tympanic membrane viewed by otoscope.png, Tympanic membrane viewed by otoscope File:Traumatic Perforation of the Tympanic Membrane.jpg, The oval perforation in this left tympanic membrane was the result of a slap on the ear File:Subtotal Perforation of the right tympanic membrane.tif, A subtotal perforation of the right tympanic membrane resulting from a previous severe otitis media File:TM RIGHT NORMAL.jpg, A normal human right tympanic membrane (eardrum) File:Frog on leaf with eardrum.jpg, Frog on leaf showing eardrum


References


External links


Diagram at Georgia State University


{{Authority control Auditory system Ear