Ear canal

Ear canal
External acoustic meatus
Ear-anatomy-text-small-en.svg
Anatomy of the human ear.
Latin meatus acusticus externus
Gray's subject #229 1036
Artery anterior part: superficial temporal artery
posterior part: posterior auricular artery
Vein superficial temporal veins, external jugular vein, pterygoid plexus
Nerve auriculotemporal nerve, great auricular nerve, auricular branch of vagus nerve
Lymph superficial cervical lymph nodes, deep cervical lymph nodes
Precursor groove (cleft) of the first branchial arch.[1]

The ear canal (external auditory meatus, external acoustic meatus) (Latin: meatus acusticus externus) , is a tube running from the outer ear to the middle ear. The human ear canal extends from the pinna to the eardrum and is about 35 mm in length and 5 to 10 mm in diameter.

Contents

Structure

The human ear canal is divided into two parts. The fibrocartilaginous part forms the outer third of the canal, Its anterior and lower wall are cartilaginous, whereas its superior and back wall are fibrous. The cartilage is the continuation of the cartilage framework of pinna. The bony part forms the inner two thirds. The bony part is much shorter in children and is only a ring (annulus tympanicus) in the newborn.

Size and shape of the canal vary among individuals. The canal is approximately 35 mm long and 5 to 10 mm in diameter. It has a sigmoid form and runs from behind and above downward and forward. On the cross-section, it is of oval shape. These are important factors to consider when fitting earplugs.

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:

Earwax

Main article: Earwax

Earwax, also known as cerumen, is a yellowish, waxy substance secreted in the ear canals. It plays an important role in the human ear canal, assisting in cleaning and lubrication, and also provides some protection from bacteria, fungi, and insects. Excess or impacted cerumen can press against the eardrum and/or occlude the external auditory canal and impair hearing.

References

  1. ^ hednk-022 — Embryology at UNC

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

v · d · eSensory system: Auditory and Vestibular systems (TA A15.3, TH 3.11.09, GA 10.1029)
Outer ear

Pinna (Helix, Antihelix, Tragus, Antitragus, Incisura anterior auris, Earlobe) • Ear canal • Auricular muscles

Eardrum (Umbo, Pars flaccida)
Middle ear

Labyrinthine wall/medial: Oval window · Round window • Secondary tympanic membrane • Prominence of facial canal • Promontory of tympanic cavity

Membranous wall/lateral

Mastoid wall/posterior: Mastoid cells • Aditus to mastoid antrum • Pyramidal eminence

Carotid wall/anterior

Tegmental wall/roof: Epitympanic recess

Jugular wall/floor
Stapedius · Tensor tympani
Bony part of pharyngotympanic tube · Cartilage of pharyngotympanic tube (Torus tubarius)
Inner ear/
(membranous labyrinth,
bony labyrinth)
General cochlea
Perilymphatic space

Reissner's/vestibular membrane • Basilar membrane

Endolymph • Stria vascularis • Spiral ligament

Organ of Corti: Stereocilia • Tectorial membrane • Sulcus spiralis (externus, internus) • Spiral limbus
Cells

M: EAR

anat(e/p)/phys/devp

noco/cong, epon

proc, drug(S2)

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Look at other dictionaries:

  • ear canal — ear canals N COUNT Your ear canal is the tube that opens in your outer ear and leads inside your ear. Hearing can be affected by ear wax blocking the ear canal …   English dictionary

  • Ear canal, self-cleaning — Most of the time the ear canals are self cleaning, that is, there is a slow and orderly migration of ear canal skin from the eardrum to the outer opening. Old earwax is constantly being transported from the deeper areas of the ear canal to the… …   Medical dictionary

  • ear canal — noun either of the passages in the outer ear from the auricle to the tympanic membrane • Syn: ↑auditory meatus, ↑acoustic meatus, ↑auditory canal, ↑external auditory canal • Hypernyms: ↑meatus • Part Holonyms: ↑ …   Useful english dictionary

  • ear canal — noun The tube or meatus running from the outer ear to the eardrum through which sound enters. Syn: acoustic meatus, auditory canal, auditory meatus, external acoustic meatus, external auditory canal …   Wiktionary

  • ear canal — /ˈɪə kənæl/ (say ear kuhnal) noun → auditory canal …  

  • ear canal — noun Date: 1930 the tubular passage of the outer ear leading to the tympanic membrane …   New Collegiate Dictionary

  • Ear mite — Otodectes cynotis Scientific classification Kingdom: Animalia Phylum …   Wikipedia

  • Ear drop — Ear drops are a form of medicine used to treat or prevent ear infections, especially infections of the outer ear and ear canal (otitis externa). Bacterial infections are sometimes treated with antibiotics. Examples are: Ciprodex ear drops… …   Wikipedia

  • ear|drum — «IHR DRUHM», noun. 1. a thin membrane across the middle ear that vibrates when sound waves strike it; tympanic membrane; tympanum: »Sound waves enter the outer ear, travel down the ear canal, and strike a thin membrane called the eardrum, which… …   Useful english dictionary

  • semicircular ear canal — fluid filled canals embedded in the cranium and concerned with balance and hearing. Gnathostomata have 3 canals, lampreys have 2 (lacking a horizontal canal), and hagfishes have only one canal, perhaps appearing secondarily by the joining of two… …   Dictionary of ichthyology

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