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Information about Eustachian Tube

Eustachian tube
Anatomy of the human ear.
The middle ear
Latintuba auditiva
subject #230 1042
Precursorfirst branchial pouch
MeSH Eustachian+tube
Dorlands/Elsevier t_21/12826987


The Eustachian tube (or auditory tube) is a tube that links the pharynx to the middle ear. In adults the Eustachian tube is approximately 35 mm long. It is named after the 16th century anatomist Eustachius.[1] Some modern medical books call this the pharyngotympanic tube.[2]

Location

The Eustachian tube extends from the anterior wall of the middle ear to the lateral wall of the nasopharynx, approximately at the level of the inferior nasal concha. A portion of the tube (~1/3) proximal to the middle ear is made of bone; the rest is composed of cartilage [3] and raises a tubal elevation, the torus tubarius, in the nasopharynx where it opens.

In the equids (horses) and some rodent-like species such as the desert hyrax, an evagination of the eustachian tube is known as the gutteral pouch and is divided into medial and lateral compartments by the stylohyoid bone of the hyoid apparatus. This is of great importance in equine medicine as the pouches are prone to infections, and due to their intimate relationship to the cranial nerves (VII,IX,X,XI) and the internal and external carotid artery, various syndromes may arise relating to which is damaged. Epistaxis (nosebleed) is a very common presentation to veterinary surgeons and this may often be fatal unless a balloon catheter can be placed in time to suppress bleeding.

Functions

Pressure equalization

Normally the Eustachian tube is closed, but it can open to let a small amount of air through to equalize the pressure between the middle ear and the atmosphere. When this happens we hear a small pop, an event familiar to aircraft passengers or drivers in mountainous regions. Yawning or swallowing can pull on muscles in the neck, causing the tube to open. Some people are born with the ability to contract just these muscles voluntarily, similar to people who can wiggle their ears. Doing so will make one's voice sound louder to oneself. Without this airway, air would be unable to escape from one's ear, the middle ear would be isolated from the atmosphere, and could be easily damaged by pressure changes.

Some who have the ability to voluntarily contract these muscles can hear a "popclickity" sound in the middle ear when actuating these muscles, and are able to hold the muscle contraction (some refer to this as 'clicking your ears to equalize the pressure'). This allows such people to voluntarily equalize pressures at will when making rapid ascents or descents, typically in aircraft flights or large elevation changes in either tall buildings or mountainous treks. When the breath (inhale or exhale) is controlled, air pressure can be intentionally increased or decreased in the middle ear (breathing through the nose only or mouth), where the feeling of a cool air breeze can be felt inside the eustachian tube.

Occasionally, if the voluntary contraction timing is missed during a rapid pressure change, a slight yawning (opening of the jaw) action combines to assist in pressure equalization.

Mucus drainage

The Eustachian tube also drains mucus from the middle ear. Upper airway infections or allergies can cause the Eustachian tube to become swollen, trapping bacteria and causing ear infections. This swelling can be reduced through the use of pseudoephedrine. Earaches are more common in children because the tube is more horizontal and thinner, making the movement of fluid harder.

Embryologic development

The Eustachian tube is derived from the first pharyngeal pouch, which during embryogenesis forms a recess called the tubotympanic sulcus. The sulcus deepens to meet the first pharyngeal cleft forming the tympanic membrane. The distal part of the tubotympanic sulcus gives rise to the tympanic cavity, while the proximal tubular structure becomes the Eustachian tube.

Muscles

There are four muscles associated with the function of the Eustachian tube:

Disorders of the Eustachian tube

Some people are born with a dysfunctional Eustachian tube, which is much slimmer than the usual human Eustachian tube. This can either be genetically, or has been suggested to be a phenomenon occurring as a result of a hard birth, in which the baby's head was subject to an extraordinary amount of pressure, thus reshaping the Eustachian tube, making it much slimmer. The result of this disorder is a huge amount of mucus gathering in the middle ear, often impairing hearing to a degree. This condition is known as otitis media or glue ear. The disorder is treated by inserting small tubes (often known as Grommets) through the tympanic membrane (ear drum). This allows any accumulation of mucus to flow directly out through the ear, as well as continually equalizing the pressure of the ear, throughout a subject's day. In some cases a person may be able to blow small amounts of air through the Eustachian tube and out through the ear, particularly if the Eustachian tubes are patulous.

Some people suffer from the rare Patulous Eustachian tube condition, in which the Eustachian tube remains intermittently open, causing an echoing sound of their own heartbeat, breathing and speech, which may be temporarily relieved by flipping the head upside down.

Additional images


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

Horizontal section through left ear; upper half of section.

View of the inner wall of the tympanum (enlarged.)

The right membrana tympani with the hammer and the chorda tympani, viewed from within, from behind, and from above.


References


 •  • [ e]
Sensory system: Auditory and Vestibular systems
Outer earPinna (Helix, Antihelix, Tragus, Antitragus, Earlobe) • Ear canal
Middle earEardrum • Ossicles (Malleus, Incus & Stapes) • Stapedius • Tensor tympani • Eustachian tube (Torus tubarius)
Inner ear/LabyrinthBony 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 systemStatic/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
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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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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In the development of vertebrate animals, Pharyngeal or branchial pouches form on the endodermal side between the branchial arches, and pharyngeal grooves (or clefts) form from the lateral ectodermal surface of the neck region to separate the arches.
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Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. Created and updated by the United States National Library of Medicine (NLM), it is used by the MEDLINE/PubMed
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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 pharynx (plural: pharynges) is the part of the neck and throat situated immediately posterior to the mouth and nasal cavity, and cranial, or superior, to the esophagus, larynx, and trachea.
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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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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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As a means of recording the passage of time, the 16th century was that century which lasted from 1501 through 1600.

See also: 16th century in literature

Events

1500s

  • 1500s: Mississippian culture disappears.

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Bartolomeo Eustachi (b. 1500 or 1514 - d. August 27, 1574), also known by his Latin name of Eustachius, was one of the founders of the science of human anatomy.

Life


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The inferior nasal concha (Inferior Turbinated Bone) is one of the turbinates in the nose. It extends horizontally along the lateral wall of the nasal cavity [Fig. 1] and consists of a lamina of spongy bone, curled upon itself like a scroll.
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torus tubarius or cushion, behind the pharyngeal orifice of the tube.

External links

  • SUNY Labs 31:14-0102
  • MedEd at Loyola grossanatomy/dissector/labs/h_n/nasal/na4_1.html
  • Roche Lexicon - illustrated navigator, at Elsevier 25420.

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The nasopharynx (nasal part of the pharynx) lies behind the nose and above the level of the soft palate: it differs from the oral and laryngeal parts of the pharynx in that its cavity always remains patent (open).
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Otitis is a general term for inflammation or infection of the ear, in both humans and other animals.

It is subdivided into the following:
  • Otitis externa or External Otitis - involves the outer ear and ear canal.

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Pseudoephedrine (commonly abbreviated as PSE) is a sympathomimetic amine commonly used as a decongestant. The salts pseudoephedrine hydrochloride and pseudoephedrine sulfate
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pharyngeal pouch is a pathological pulsion diverticulum of the pharyngeal mucosa through Killian's dehiscence. Killian's dehiscence (also known as Killian's triangle) is a triangular area in the wall of the pharynx between the inferior constrictor muscle and the cricopharyngeus
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Embryogenesis is the process by which the embryo is formed and develops. It starts with the fertilization of the ovum, egg, which, after fertilization, is then called a zygote.
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In the development of vertebrate animals, the pharyngeal arches (also called branchial arches or gill arches in fish) develop during the fourth and fifth week in utero
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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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The tympanic cavity is a small cavity surrounding the bones of the middle ear.

It is formed from the tubotympanic sulcus, an expansion of the first pharyngeal pouch.
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The levator veli palatini is a muscle of the human body. During swallowing, it contracts, elevating the soft palate to help prevent food from entering the nasopharynx. It is innervated via the pharyngeal plexus, primarily by the vagus nerve (CN X).
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The vagus nerve (also called pneumogastric nerve or cranial nerve X) is the tenth of twelve paired cranial nerves, and is the only nerve that starts in the brainstem (within the medulla oblongata) and extends, through the jugular foramen, down below the head, to the
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The salpingopharyngeus muscle arises from the inferior part of the cartilage of the auditory tube in the nasal cavity; it passes downward and blends with the posterior fasciculus of the pharyngopalatinus muscle.
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The tensor tympani, the larger of the two muscles of the tympanic cavity, is contained in the bony canal above the osseous portion of the auditory tube, from which it is separated by the septum canalis musculotubarii.
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The mandibular nerve (V3) is the largest of the three branches of the trigeminal nerve.

Structure

Roots

It is made up of two roots:
  • a large sensory root proceeding from the inferior angle of the trigeminal ganglion.

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The tensor veli palatini (tensor palati) is a broad, thin, ribbon-like muscle in the head that tenses the soft palate.

Structure

The tensor veli palatini it is found lateral to the levator veli palatini muscle.
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Patulous Eustachian tube is the name of a rare physical disorder where the Eustachian tube, which is normally closed, instead stays intermittently open. As a result, when it is open, all of the patient's breathing, talking, swallowing, heart beat, etc.
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Who Named It? is an English-language dictionary of medical eponyms and the people associated with their identification. Though this is a dictionary, many eponyms and persons are presented in extensive articles with comprehensive bibliographies.
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eMedicine is an online clinical medical knowledge base that was founded in 1996 by Scott Plantz and Richard Lavely, two medical doctors. It was sold to WebMD in January 2006.
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University of Michigan Health System is the wholly-owned academic medical center of the University of Michigan in Ann Arbor. It includes the UM Medical School, with its Faculty Group Practice and many research laboratories; and the UM Hospitals and Health Centers unit, which
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