What is Ear Canal?

Information about Ear Canal

Ear canal

Anatomy of the human ear.
Latin	meatus acusticus externus
	subject #229 1036
Artery	anterior auricular branches
Precursor	groove (cleft) of the first branchial arch.^[1]
Dorlands/Elsevier	m_06/12518132

The ear canal (external auditory meatus, external acoustic meatus), is a tube running from the outer ear to the middle ear. The ear canal extends from the pinna to the eardrum and is about 26 mm in length and 7 mm in diameter.

Size and shape

The ear canal is approximately 25mm long and 8mm in diameter. Size and shape of the canal vary among individuals. This is an important factor to consider when fitting hearing protectors.

Disorders

The ear canal, because of its relative exposure to the outside world, is a common victim of diseases and other disorders. Some disorders include:

Otitis externa (swimmer's ear), bacteria-caused inflammation of the ear canal
Contact dermatitis of the ear canal
Ear fungus
Ear myiasis, an extremely rare infestation of maggots
Bone exposure, caused by the wearing away of skin in the canal
Granuloma, a scar usually caused by tympanostomy tubes
Stenosis, a gradual closing of the canal
Foreign body in ear

References

1. ^ Embryology at UNC hednk-022

Additional images

Base of skull. Inferior surface.

Left infratemporal fossa.

External and middle ear, opened from the front. Right side.

Horizontal section through left ear; upper half of section.

External links

• • [ e] Sensory system: Auditory and Vestibular systems
Outer ear	Pinna (Helix, Antihelix, Tragus, Antitragus, Earlobe) • Ear canal
Middle ear	Eardrum • Ossicles (Malleus, Incus & Stapes) • Stapedius • Tensor tympani • Eustachian tube (Torus tubarius)
Inner ear/Labyrinth	Bony labyrinth (Vestibule) • Membranous labyrinth Oval window • Helicotrema • Round window Cochlea: Spiral ganglion • Modiolus • Cochlear duct/scala media (Endolymph, Stria vascularis, Spiral ligament, Organ of Corti) • Scala vestibuli and Scala tympani (Perilymph) Reissner's/vestibular membrane • Basilar membrane • Tectorial membrane Organ of Corti: Hair cells • Stereocilia • Sulcus spiralis (externus, internus) • Limbus spiralis
Vestibular system	Static/translations: Utricle (Macula) - Saccule (Macula, Endolymphatic sac, Endolymphatic duct) - Kinocilium - Otolith Kinetic/rotations: Semicircular canals (Superior, Posterior, Horizontal) • Cupula • Ampullae (Crista ampullaris)
Brain (auditory)	Cochlear nerve ^VIII → Cochlear nuclei → Superior olivary nuclei → Lateral lemniscus → Inferior colliculi → Medial geniculate nuclei → Primary auditory cortex

• • [ e] Foramina of the skull (and canals and fissures)
Foramina	cecum - ethmoidal (anterior, posterior) - incisive - jugular - lacerum - magnum - mandibular - mastoid - mental - optic - orbital (infraorbital, supraorbital) - ovale - palatine (greater, lesser) - parietal - rotundum - sphenopalatine - spinosum - stylomastoid - zygomaticofacial - zygomaticotemporal
Canals	carotid - condylar - hypoglossal - incisive - pterygoid
Fissures	orbital (inferior, superior) - petrotympanic
other	external acoustic meatus - internal acoustic meatus - cribriform plate

Latin
Official status
Official language of: Vatican City
Used for official purposes, but not spoken in everyday speech
Regulated by: Opus Fundatum Latinitas
Roman Catholic Church
Language codes
ISO 639-1: la
ISO 639-2: lat
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Arteries are muscular blood vessels that carry blood away from the heart.^[1] All arteries, with the exception of the pulmonary and umbilical arteries, carry oxygenated blood.

The circulatory system is extremely important for sustaining life.
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The anterior auricular branches of the superficial temporal artery are distributed to the anterior portion of the auricula, the lobule, and part of the external meatus, anastomosing with the posterior auricular.
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Embryology is the study of the development of an embryo. An embryo is defined as any vertebrate in a stage before birth or hatching. Embryology refers to the development of the egg cell (zygote) after fertilization and the differentiation of cells into tissues and organs.
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The first branchial arch, also called the first pharyngeal arch and mandibular arch, is the first of six branchial arches that develops in fetal life. It is located between the stomodeum and the first pharyngeal groove.
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Elsevier, the world's largest publisher of medical and scientific literature, forms part of the Reed Elsevier group. Based in Amsterdam, the company has substantial operations in the UK, USA and elsewhere.
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The outer ear is the external portion of the ear.

Pinna, or auricle

The visible part is called the pinna and functions to collect and focus sound waves. Many mammals can move the pinna (with the auriculares muscles) in order to focus their hearing in a certain direction
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The middle ear is the portion of the ear internal to the eardrum, and external to the oval window of the cochlea. The mammalian middle ear contains three ossicles, which couple vibration of the eardrum into waves in the fluid and membranes of the inner ear.
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The pinna (Latin for feather) is the visible part of the ear that resides outside of the head (this may also be referred to as the auricle or auricula).

Purpose

The purpose of the pinna is to collect sound.
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The tympanic membrane, colloquially known as the eardrum, is a thin membrane that separates the external ear from the middle ear. Its function is to transmit sound vibrations from the air, conducted through the external acoustic meatus to the ossicles inside the
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1 millimetre =
SI units
010⁻³ m 0 cm
US customary / Imperial units
010⁻³ ft 010⁻³ in

The millimetre (American spelling: millimeter, symbol mm
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Hearing protectors are devices designed to prevent Noise-Induced Hearing Loss (NIHL), a type of post-lingual hearing impairment.

Earplug - A device inserted into the ear canal.
Earmuffs - Objects designed to cover a person's ears.

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Otitis externa
Classification & external resources

ICD-10 H60
ICD-9 380.1 - 380.2

DiseasesDB 9401
MedlinePlus 000622
eMedicine ped/1688 emerg/350 Otitis externa ("swimmer's ear") is an inflammation of the outer ear and ear canal.
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Contact dermatitis
Classification & external resources

ICD-10 L 25.9
ICD-9 692.9

DiseasesDB 29585

eMedicine emerg/131 ped/2569 oph/480
MeSH D003877

Contact dermatitis
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Myiasis
Classification & external resources

ICD-10 B87
ICD-9 134.0

Myiasis is an animal or human disease caused by parasitic dipterous fly larvae feeding on the host's necrotic or living tissue.
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granuloma seen in the colon of a patient with Crohn's disease

MeSH D006099 In medicine (anatomical pathology), a granuloma is a group of epithelioid macrophages surrounded by a lymphocyte cuff.
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Scars are areas of fibrous tissue that replace normal skin (or other tissue) after injury. A scar results from the biologic process of wound repair in the skin and other tissues of the body. Thus, scarring is a natural part of the healing process.
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Tympanostomy tube is a small tube inserted into the eardrum in order to keep the middle ear aerated for a prolonged period of time. The operation to insert the tube involves a myringotomy. The tube itself is made in a variety of designs and materials.
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A stenosis is an abnormal narrowing in a blood vessel or other tubular organ or structure. It is also sometimes called a "stricture" (as in urethral stricture).

Stenoses of the vascular type are often associated with a noise (bruit) resulting from turbulent flow over the
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University of North Carolina at Chapel Hill is a public, coeducational, research university located in Chapel Hill, North Carolina, United States. Also known as The University of North Carolina, Carolina, North Carolina, or simply UNC
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sensory system: in this case, vision, for the visual system. ]]

A sensory system is a part of the nervous system responsible for processing sensory information.
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The auditory system is the sensory system for the sense of hearing.

Ear

Main article: Ear

Outer ear

Main article: Outer ear

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The vestibular system, or balance system, is the sensory system that provides the dominant input about our movement and orientation in space. Together with the cochlea, the auditory organ, it is situated in the vestibulum in the inner ear (Figure 1).
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The outer ear is the external portion of the ear.

Pinna, or auricle

The pinna (Latin for feather) is the visible part of the ear that resides outside of the head (this may also be referred to as the auricle or auricula).

Purpose

The purpose of the pinna is to collect sound.
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The prominent rim of the auricula is called the helix. Where the helix turns downward behind, a small tubercle is frequently seen: the auricular tubercle of Darwin.

Additional images

The muscles of the auricula.

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antihelix, also known as the anthelix; this divides above into two crura, between which is a triangular depression, the fossa triangularis.

Additional images

The muscles of the auricula.

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tragus, so called from its being generally covered on its under surface with a tuft of hair, resembling a goat’s beard, "goat" being the origin of the word, from the Greek tragos.
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