Larynx

Information about Larynx



Conducting passages

Cut through the larynx of a horse 1 hyoid bone 2 epiglottis 3 vestibular fold 4 vocal fold 5 Ventricularis muscle 6 ventricle of larynx 7 Vocalis muscle 8 Adam's apple 9 rings of cartilage 10 infraglottic cavity 11 first bronchial tube cartilage 12 bronchial tube
	subject #236 1072
Artery	superior laryngeal, inferior laryngeal
Nerve	superior laryngeal (ext and int), recurrent laryngeal
MeSH	Larynx

The larynx (plural larynges), colloquially known as the voicebox, is an organ in the neck of mammals involved in protection of the trachea and sound production. The larynx houses the vocal folds, and is situated just below where the tract of the pharynx splits into the trachea and the esophagus.

Function

Sound is generated in the larynx, and that is where pitch and volume are manipulated. The strength of expiration from the lungs also contributes to loudness, and is necessary for the vocal folds to produce speech.

Fine manipulation of the larynx is used in a great way to generate a source sound with a particular fundamental frequency, or pitch. This source sound is altered as it travels through the vocal tract, configured differently based on the position of the tongue, lips, mouth, and pharynx. The process of altering a source sound as it passes through the filter of the vocal tract creates the many different vowel and consonant sounds of the world's languages.

During swallowing, the larynx (at the epiglottis and at the glottis) closes to prevent swallowed material from entering the lungs; the larynx is also pulled upwards to assist this process. Stimulation of the larynx by ingested matter produces a strong cough reflex to protect the lungs.

The vocal folds can be held close together (by adducting the arytenoid cartilages), so that they vibrate (see phonation). The muscles attached to the arytenoid cartilages control the degree of opening. Vocal fold length and tension can be controlled by rocking the thyroid cartilage forward and backward on the cricoid cartilage, and by manipulating the tension of the muscles within the vocal folds. This causes the pitch produced during phonation to rise or fall.

Innervation

The larynx is innervated by branches of the vagus nerve (CN X) on each side. Sensory innervation to the glottis and supraglottis is by the internal branch of the superior laryngeal nerve. The external branch of the superior laryngeal nerve innervates the cricothyroid muscle. Motor innervation to all other muscles of the larynx and sensory innervation to the subglottis is by the recurrent laryngeal nerve.

Injury to the external laryngeal nerve causes weakened phonation because the vocal cords cannot be tightened. Injury to one of the recurrent laryngeal nerves produces hoarseness, if both are damaged the voice is completely lost and breathing becomes difficult.

Muscles associated with the larynx

Cricothyroid muscle lengthens and stretches the vocal cords.
Posterior cricoarytenoid muscle abducts the vocal cords.
Lateral cricoarytenoid muscle adducts the vocal cords.
Thyroarytenoid muscle (also called vocalis muscle) shortens vocal cords.
Transverse arytenoid muscle adducts the vocal folds.

Notably, the only muscle capable of separating the vocal cords for normal breathing is the posterior cricoarytenoid. If this muscle is incapacitated on both sides, the inability to pull the vocal cords apart (abduct) will cause difficulty breathing. Bilateral injury to the recurrent laryngeal nerve would cause this condition.

Descended larynx

In most animals, including infant humans and apes, the larynx is situated very high in the throat — a position that allows it to couple more easily with the nasal passages, so that breathing and eating are not done with the same apparatus. However, some aquatic mammals, large deer, and adult humans have descended larynges. An adult human cannot raise the larynx enough to directly couple it to the nasal passage.

Some linguists have suggested that the descended larynx, by extending the length of the vocal tract and thereby increasing the variety of sounds humans could produce, was a critical element in the development of speech and language. Others cite the presence of descended larynges in non-linguistic animals, as well as the ubiquity of nonverbal communication and language among humans, as counterevidence against this claim.

Disorders of the larynx

There are several things that can cause a larynx to not function properly. Some symptoms are hoarseness, loss of voice, pain in the throat or ears, and breathing difficulties.

Acute laryngitis is the sudden inflammation and swelling of the larynx. It is caused by the common cold or by excessive shouting. It is not serious. Chronic laryngitis is caused by smoking, dust, frequent yelling, or prolonged exposure to polluted air. It is much more serious than acute laryngitis.
Presbylarynx is a condition in which age-related atrophy of the soft tissues of the larynx results in weak voice and restricted vocal range and stamina. Bowing of the anterior portion of the vocal cords is found on laryngoscopy.
Ulcers may be caused by the prolonged presence of an endotracheal tube.
Polyps and nodules are small bumps on the vocal cords caused by prolonged exposure to cigarette smoke and vocal overuse, respectively.
Two related types of cancer of the larynx, namely squamous cell carcinoma and verrucous carcinoma, are strongly associated with repeated exposure to cigarette smoke and alcohol.
Vocal cord paresis is weakness of one or both vocal folds that can greatly impact daily life.
The world's first successful larynx transplant took place in 1999 at the Cleveland Clinic. ^[1]

Cartilages

The cartilages of the larynx are the thyroid, cricoid, arytenoids, corniculates, and the cuneiforms.

The cartilages of the larynx. Posterior view.

Images

Bronchi, bronchial tree, and lungs	Larynx	The ligaments of the larynx. Antero-lateral view.
Sagittal section of the larynx and upper part of the trachea.	Coronal section of larynx and upper part of trachea.	The entrance to the larynx, viewed from behind.	Laryngoscopic view of interior of larynx.
Sagittal section of nose mouth, pharynx, and larynx.	Endoscopic image of larynx seen at the time of intubation of the esophagus during gastroscopy.

References

1. ^ [1]

Speech and Hearing Science: Anatomy and Physiology 3rd edition. Willard R. Zemlin. 1988. Prentice-Hall, Inc. Englewood Cliffs, New Jersey. ISBN 0-13-827429-0

The hyoid bone (Lingual Bone) is a bone in the human neck, and is the only bone in the skeleton not articulated to any other bone. It is supported by the muscles of the neck and in turn supports the root of the tongue.
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The epiglottis is a lid-like flap of elastic cartilage tissue covered with a mucus membrane, attached to the root of the tongue. It projects obliquely upwards behind the tongue and the hyoid bone.
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The vestibular fold (ventricular fold, superior or false vocal cord) is one of two thick folds of mucous membrane, each enclosing a narrow band of fibrous tissue, the ventricular ligament which is attached in front to the angle of the thyroid cartilage
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The vocal folds, also known popularly as vocal cords, are composed of twin infoldings of mucous membrane stretched horizontally across the larynx. They vibrate, modulating the flow of air being expelled from the lungs during phonation.
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The Thyroarytenoid is a broad, thin, muscle which lies parallel with and lateral to the vocal fold, and supports the wall of the ventricle and its appendix.

Origin and insertion

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The ventricle of the larynx (laryngeal sinus) is a fusiform fossa, situated between the ventricular and vocal folds on either side, and extending nearly their entire length.
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The Thyroarytenoid is a broad, thin, muscle which lies parallel with and lateral to the vocal fold, and supports the wall of the ventricle and its appendix.

Origin and insertion

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Cartilage is a type of dense connective tissue. It is composed of collagen fibers and/or elastin fibers, and can supply smooth surfaces for the movement of articulating bones.
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The infraglottic cavity is the portion of the larynx below the ventricles of the larynx and rima glottidis.

External links

Human anatomy at Dartmouth part_8/chapter_53.html
Human anatomy at Dartmouth figures/chapter_53/53-10.

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A bronchus (plural bronchi, adjective bronchial) is a caliber of airway in the respiratory tract that conducts air into the lungs. No gas exchange takes place in this part of the lungs.
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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 superior laryngeal artery accompanies the internal laryngeal branch of the superior laryngeal nerve, beneath the Thyreohyoideus.

It pierces the hyothyroid membrane, and supplies the muscles, mucous membrane, and glands of the larynx, anastomosing with the branch from
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The inferior laryngeal artery ascends upon the trachea to the back part of the larynx under cover of the Constrictor pharyngis inferior, in company with the recurrent nerve, and supplies the muscles and mucous membrane of this part, anastomosing with the branch from the opposite
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A nerve is an enclosed, cable-like bundle of axons (the long, slender projection of a neuron). Neurons are sometimes called nerve cells, though this term is technically imprecise since many neurons do not form nerves, and nerves also include the glial cells that
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The superior laryngeal nerve arises from the middle of the ganglion nodosum and in its course receives a branch from the superior cervical ganglion of the sympathetic.
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The external laryngeal nerve is the smaller, external branch (ramus externus) of the superior laryngeal nerve. It descends on the larynx, beneath the sternothyroid muscle, to supply the cricothyroid muscle.
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The internal laryngeal nerve is the internal branch (ramus internus) of the superior laryngeal nerve. It descends to the hyothyroid membrane, pierces it in company with the superior laryngeal artery, and is distributed to the mucous membrane of the larynx.
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The recurrent laryngeal nerve is a branch of the vagus nerve (tenth cranial nerve) that supplies motor function and sensation to the larynx (voice box). It travels within the endoneurial sheath.
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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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organ (Latin: organum, "instrument, tool") is a group of tissues that perform a specific function or group of functions. Usually there is a main tissue and sporadic tissues. The main tissue is the one that is unique for the specific organ.
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The neck is the part of the body on many limbed vertebrates that distinguishes the head from the torso or trunk.

Anatomy of the human neck

Bony anatomy: The cervical spine

The cervical portion of the human spine
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Mammalia
Linnaeus, 1758

Subclasses & Infraclasses

Subclass †Allotheria*
Subclass Prototheria
Subclass Theria

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trachea, or windpipe, is a tube that has an inner diameter of about 20-25 mm and a length of about 10-16cm. It extends from the larynx to the primary (main) bronchi in mammals, and from the pharynx to the syrinx in birds, allowing the passage of air to the lungs.
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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 esophagus (also spelled oesophagus/œsophagus, Greek οἰσοφάγος), or gullet
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Pitch is the perceived fundamental frequency of a sound. While the actual fundamental frequency can be precisely determined through physical measurement, it may differ from the perceived pitch because of overtones, or partials, in the sound.
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Loudness is the quality of a sound that is the primary psychological correlate of physical strength (amplitude).

Loudness, a subjective measure, is often confused with objective measures of sound pressure such as decibels or intensity.
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This article is copied from an article on Wikipedia.org - the free encyclopedia created and edited by online user community. The text was not checked or edited by anyone on our staff. Although the vast majority of the wikipedia encyclopedia articles provide accurate and timely information please do not assume the accuracy of any particular article. This article is distributed under the terms of GNU Free Documentation License.

Herod_Archelaus

• • [ e] General anatomy of neck (Throat • Pharynx • Larynx)
Cartilages	Cricoid • Thyroid (Adam's apple) • Epiglottis • Arytenoid • Cuneiform • Corniculate
Ligaments	Extrinsic ligaments: Thyrohyoid membrane (Lateral thyrohyoid ligament, Median thyrohyoid ligament) • Hyoepiglottic ligament • Cricotracheal ligament Intrinsic ligaments: Cricothyroid ligament
Folds and related structures	Folds: (Glossoepiglottic, Aryepiglottic, Vocal, Vestibular) • Vocal ligament • Ventricle of the larynx • Infraglottic cavity • Vestibule of larynx • Rima glottidis • Glottis
Triangles of the neck	Anterior of the neck (Muscular, Carotid, Submandibular, Submental) • Posterior of the neck (Occipital, Subclavian) • Suboccipital
Fascia	Deep cervical fascia (Pretrachial fascia, Prevertebral fascia, Investing layer) • Carotid sheath
Other	Retropharyngeal space

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Larynx

Information about Larynx

Function

Innervation

Muscles associated with the larynx

Descended larynx

Disorders of the larynx

Cartilages

Images

See also

References

Origin and insertion

Origin and insertion

External links

Anatomy of the human neck

Bony anatomy: The cervical spine