Larynx

Larynx

Overview
The larynx commonly called the voice box, is an organ
Organ (anatomy)
In biology, an organ is a collection of tissues joined in structural unit to serve a common function. Usually there is a main tissue and sporadic tissues . The main tissue is the one that is unique for the specific organ. For example, main tissue in the heart is the myocardium, while sporadic are...

 in the neck
Neck
The neck is the part of the body, on many terrestrial or secondarily aquatic vertebrates, that distinguishes the head from the torso or trunk. The adjective signifying "of the neck" is cervical .-Boner anatomy: The cervical spine:The cervical portion of the human spine comprises seven boney...

 of amphibians, reptiles (incl. birds) and mammals (including humans) involved in breathing, sound production, and protecting the trachea
Vertebrate trachea
In tetrapod anatomy the trachea, or windpipe, is a tube that connects the pharynx or larynx to the lungs, allowing the passage of air. It is lined with pseudostratified ciliated columnar epithelium cells with goblet cells that produce mucus...

 against food aspiration. It manipulates pitch
Pitch (music)
Pitch is an auditory perceptual property that allows the ordering of sounds on a frequency-related scale.Pitches are compared as "higher" and "lower" in the sense associated with musical melodies,...

 and volume
Sound pressure
Sound pressure or acoustic pressure is the local pressure deviation from the ambient atmospheric pressure caused by a sound wave. Sound pressure can be measured using a microphone in air and a hydrophone in water...

. The larynx houses the vocal folds (commonly but improperly termed the "vocal cords"), which are essential for phonation
Phonation
Phonation has slightly different meanings depending on the subfield of phonetics. Among some phoneticians, phonation is the process by which the vocal folds produce certain sounds through quasi-periodic vibration. This is the definition used among those who study laryngeal anatomy and physiology...

. The vocal folds are situated just below where the tract of the pharynx
Pharynx
The human pharynx is the part of the throat situated immediately posterior to the mouth and nasal cavity, and anterior to the esophagus and larynx. The human pharynx is conventionally divided into three sections: the nasopharynx , the oropharynx , and the laryngopharynx...

 splits into the trachea
Vertebrate trachea
In tetrapod anatomy the trachea, or windpipe, is a tube that connects the pharynx or larynx to the lungs, allowing the passage of air. It is lined with pseudostratified ciliated columnar epithelium cells with goblet cells that produce mucus...

 and the esophagus
Esophagus
The esophagus is an organ in vertebrates which consists of a muscular tube through which food passes from the pharynx to the stomach. During swallowing, food passes from the mouth through the pharynx into the esophagus and travels via peristalsis to the stomach...

.

In adult humans, the larynx is found in the anterior neck at the level of the C3–C6 vertebrae.
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Encyclopedia
The larynx commonly called the voice box, is an organ
Organ (anatomy)
In biology, an organ is a collection of tissues joined in structural unit to serve a common function. Usually there is a main tissue and sporadic tissues . The main tissue is the one that is unique for the specific organ. For example, main tissue in the heart is the myocardium, while sporadic are...

 in the neck
Neck
The neck is the part of the body, on many terrestrial or secondarily aquatic vertebrates, that distinguishes the head from the torso or trunk. The adjective signifying "of the neck" is cervical .-Boner anatomy: The cervical spine:The cervical portion of the human spine comprises seven boney...

 of amphibians, reptiles (incl. birds) and mammals (including humans) involved in breathing, sound production, and protecting the trachea
Vertebrate trachea
In tetrapod anatomy the trachea, or windpipe, is a tube that connects the pharynx or larynx to the lungs, allowing the passage of air. It is lined with pseudostratified ciliated columnar epithelium cells with goblet cells that produce mucus...

 against food aspiration. It manipulates pitch
Pitch (music)
Pitch is an auditory perceptual property that allows the ordering of sounds on a frequency-related scale.Pitches are compared as "higher" and "lower" in the sense associated with musical melodies,...

 and volume
Sound pressure
Sound pressure or acoustic pressure is the local pressure deviation from the ambient atmospheric pressure caused by a sound wave. Sound pressure can be measured using a microphone in air and a hydrophone in water...

. The larynx houses the vocal folds (commonly but improperly termed the "vocal cords"), which are essential for phonation
Phonation
Phonation has slightly different meanings depending on the subfield of phonetics. Among some phoneticians, phonation is the process by which the vocal folds produce certain sounds through quasi-periodic vibration. This is the definition used among those who study laryngeal anatomy and physiology...

. The vocal folds are situated just below where the tract of the pharynx
Pharynx
The human pharynx is the part of the throat situated immediately posterior to the mouth and nasal cavity, and anterior to the esophagus and larynx. The human pharynx is conventionally divided into three sections: the nasopharynx , the oropharynx , and the laryngopharynx...

 splits into the trachea
Vertebrate trachea
In tetrapod anatomy the trachea, or windpipe, is a tube that connects the pharynx or larynx to the lungs, allowing the passage of air. It is lined with pseudostratified ciliated columnar epithelium cells with goblet cells that produce mucus...

 and the esophagus
Esophagus
The esophagus is an organ in vertebrates which consists of a muscular tube through which food passes from the pharynx to the stomach. During swallowing, food passes from the mouth through the pharynx into the esophagus and travels via peristalsis to the stomach...

.

Anatomical position and description


In adult humans, the larynx is found in the anterior neck at the level of the C3–C6 vertebrae. It connects the inferior part of the pharynx
Pharynx
The human pharynx is the part of the throat situated immediately posterior to the mouth and nasal cavity, and anterior to the esophagus and larynx. The human pharynx is conventionally divided into three sections: the nasopharynx , the oropharynx , and the laryngopharynx...

 (hypopharynx) with the trachea
Vertebrate trachea
In tetrapod anatomy the trachea, or windpipe, is a tube that connects the pharynx or larynx to the lungs, allowing the passage of air. It is lined with pseudostratified ciliated columnar epithelium cells with goblet cells that produce mucus...

. The laryngeal skeleton
Skeleton
The skeleton is the body part that forms the supporting structure of an organism. There are two different skeletal types: the exoskeleton, which is the stable outer shell of an organism, and the endoskeleton, which forms the support structure inside the body.In a figurative sense, skeleton can...

 consists of nine cartilage
Cartilage
Cartilage is a flexible connective tissue found in many areas in the bodies of humans and other animals, including the joints between bones, the rib cage, the ear, the nose, the elbow, the knee, the ankle, the bronchial tubes and the intervertebral discs...

s: three single (epiglottic, thyroid
Thyroid cartilage
The thyroid cartilage is the largest of the nine cartilages that make up the laryngeal skeleton, the cartilage structure in and around the trachea that contains the larynx....

 and cricoid) and three paired (arytenoid
Arytenoid cartilage
The arytenoid cartilages are a pair of small three-sided pyramids which form part of the larynx, to which the vocal folds are attached...

, corniculate
Corniculate cartilages
The corniculate cartilages are two small conical nodules consisting of yellow elastic cartilage, which articulate with the summits of the arytenoid cartilages and serve to prolong them posteriorly and medially....

, and cuneiform). The hyoid bone
Hyoid bone
The hyoid bone is a horseshoe-shaped bone situated in the anterior midline of the neck between the chin and the thyroid cartilage. At rest, it lies at the level of the base of the mandible in the front and the third cervical vertebra behind.Unlike other bones, the hyoid is only distantly...

 is not part of the larynx, though it is connected to it. The larynx extends vertically from the tip of the epiglottis
Epiglottis
The epiglottis is a flap that is made of elastic cartilage tissue covered with a mucous membrane, attached to the entrance of the larynx. It projects obliquely upwards behind the tongue and the hyoid bone, pointing dorsally. The term, like tonsils, is often incorrectly used to refer to the uvula...

 to the inferior border of the cricoid cartilage. Its interior can be divided in supraglottis, glottis
Glottis
The glottis is defined as the combination of the vocal folds and the space in between the folds .-Function:...

 and subglottis.

In newborn infants, the larynx is initially at the level of the C2–C3 vertebrae, and is further forward and higher relative to its position in the adult body. The larynx descends as the child grows.

Function


Sound is generated in the larynx, and that is where pitch
Pitch (music)
Pitch is an auditory perceptual property that allows the ordering of sounds on a frequency-related scale.Pitches are compared as "higher" and "lower" in the sense associated with musical melodies,...

 and volume
Loudness
Loudness is the quality of a sound that is primarily a psychological correlate of physical strength . More formally, it is defined as "that attribute of auditory sensation in terms of which sounds can be ordered on a scale extending from quiet to loud."Loudness, a subjective measure, is often...

 are manipulated. The strength of expiration
Expiration
Expiration is an independent feature film written, directed and starring Gavin Heffernan. It was the winner of the Grand Jury Prize and Best Film at the Canadian Filmmakers' Festival....

 from the lungs also contributes to loudness.

Fine manipulation of the larynx is used to generate a source sound with a particular fundamental frequency, or pitch. This source sound is altered as it travels through the vocal tract
Vocal tract
The vocal tract is the cavity in human beings and in animals where sound that is produced at the sound source is filtered....

, configured differently based on the position of the tongue
Tongue
The tongue is a muscular hydrostat on the floors of the mouths of most vertebrates which manipulates food for mastication. It is the primary organ of taste , as much of the upper surface of the tongue is covered in papillae and taste buds. It is sensitive and kept moist by saliva, and is richly...

, lips
Lip
Lips are a visible body part at the mouth of humans and many animals. Lips are soft, movable, and serve as the opening for food intake and in the articulation of sound and speech...

, mouth
Mouth
The mouth is the first portion of the alimentary canal that receives food andsaliva. The oral mucosa is the mucous membrane epithelium lining the inside of the mouth....

, and pharynx
Pharynx
The human pharynx is the part of the throat situated immediately posterior to the mouth and nasal cavity, and anterior to the esophagus and larynx. The human pharynx is conventionally divided into three sections: the nasopharynx , the oropharynx , and the laryngopharynx...

. 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 as well as tone, certain realizations of stress and other types of linguistic prosody. The larynx also has a similar function as the lungs in creating pressure differences required for sound production; a constricted larynx can be raised or lowered affecting the volume of the oral cavity as necessary in glottalic consonants.

The vocal folds can be held close together (by adducting the arytenoid cartilages), so that they vibrate (see phonation
Phonation
Phonation has slightly different meanings depending on the subfield of phonetics. Among some phoneticians, phonation is the process by which the vocal folds produce certain sounds through quasi-periodic vibration. This is the definition used among those who study laryngeal anatomy and physiology...

). 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
Thyroid cartilage
The thyroid cartilage is the largest of the nine cartilages that make up the laryngeal skeleton, the cartilage structure in and around the trachea that contains the larynx....

 forward and backward on the cricoid cartilage (either directly by contracting the cricothyroids or indirectly by changing the vertical position of the larynx), by manipulating the tension of the muscles within the vocal folds, and by moving the arytenoids forward or backward. This causes the pitch produced during phonation
Phonation
Phonation has slightly different meanings depending on the subfield of phonetics. Among some phoneticians, phonation is the process by which the vocal folds produce certain sounds through quasi-periodic vibration. This is the definition used among those who study laryngeal anatomy and physiology...

 to rise or fall. In most males the vocal folds are longer and with a greater mass, producing a deeper pitch.

The vocal apparatus consists of two pairs of mucosal folds. These folds are false vocal folds (vestibular folds) and true vocal folds (folds). The false vocal folds are covered by respiratory epithelium, while the true vocal folds are covered by stratified squamous epithelium. The false vocal folds are not responsible for sound production, but rather for resonance. The exceptions to this are found in Tibetan Chant and Kargyraa, a style of Tuvan throat singing. Both make use of the false vocal folds to create an undertone. These false vocal folds do not contain muscle, while the true vocal folds do have skeletal muscle.

During swallowing
Swallowing
Swallowing, known scientifically as deglutition, is the process in the human or animal body that makes something pass from the mouth, to the pharynx, and into the esophagus, while shutting the epiglottis. If this fails and the object goes through the trachea, then choking or pulmonary aspiration...

, the backward motion of the tongue forces the epiglottis over the glottis' opening to prevent swallowed material from entering the larynx which leads to the lung
Lung
The lung is the essential respiration organ in many air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located near the backbone on either side of the heart...

s; the larynx is also pulled upwards to assist this process. Stimulation of the larynx by ingested matter produces a strong cough
Cough
A cough is a sudden and often repetitively occurring reflex which helps to clear the large breathing passages from secretions, irritants, foreign particles and microbes...

 reflex
Reflex
A reflex action, also known as a reflex, is an involuntary and nearly instantaneous movement in response to a stimulus. A true reflex is a behavior which is mediated via the reflex arc; this does not apply to casual uses of the term 'reflex'.-See also:...

 to protect the lungs.

Innervation


The larynx is innervated by branches of the vagus nerve
Vagus nerve
The vagus nerve , also called pneumogastric nerve or cranial nerve X, is the tenth of twelve paired cranial nerves...

 on each side. Sensory innervation to the glottis and laryngeal vestibule is by the internal branch of the superior laryngeal nerve
Superior laryngeal nerve
The superior laryngeal nerve is a branch of the vagus nerve. It arises from the middle of the ganglion nodosum and in its course receives a branch from the superior cervical ganglion of the sympathetic....

. The external branch of the superior laryngeal nerve innervates the cricothyroid muscle
Cricothyroid muscle
The cricothyroid muscle is the only tensor muscle of the larynx, aiding with phonation. It attaches to the anterolateral aspect of the cricoid and the inferior cornu and lower lamina of the thyroid cartilage, and its action tilts the thyroid forward to help tense the vocal cords...

. Motor innervation to all other muscles of the larynx and sensory innervation to the subglottis is by the recurrent laryngeal nerve
Recurrent laryngeal nerve
The recurrent laryngeal nerve is a branch of the vagus nerve that supplies motor function and sensation to the larynx . It travels within the endoneurium...

. While the sensory input described above is (general) visceral sensation (diffuse, poorly localized), the vocal fold also receives general somatic sensory innervation (proprioceptive and touch) by the superior laryngeal nerve.

Injury to the external laryngeal nerve causes weakened phonation because the vocal folds cannot be tightened. Injury to one of the recurrent laryngeal nerves produces hoarseness, if both are damaged the voice may or may not be preserved, but breathing becomes difficult.

Intrinsic muscles associated with the larynx

  • Cricothyroid muscles lengthen and stretch the vocal folds.
  • Posterior cricoarytenoid muscle
    Posterior cricoarytenoid muscle
    The posterior cricoarytenoid muscles are extremely small, paired muscles that extend from the posterior cricoid cartilage to the arytenoid cartilages in the larynx. By rotating the arytenoid cartilages laterally, these muscles abduct the vocal cords and thereby open the rima glottidis. Their action...

    s abduct and externally rotate the arytenoid cartilages, resulting in abducted vocal folds.
  • Lateral cricoarytenoid muscle
    Lateral cricoarytenoid muscle
    The lateral cricoarytenoid muscles extend from the lateral cricoid cartilage to the ipsilateral arytenoid cartilage. By rotating the arytenoid cartilages medially, these muscles adduct the vocal cords and thereby close the rima glottidis, protecting the airway...

    s adduct and internally rotate the arytenoid cartilages, which can result in adducted vocal folds.
  • Transverse arytenoid muscle adducts the arytenoid cartilages, resulting in adducted vocal folds.
  • Oblique arytenoid muscles narrow the laryngeal inlet by constricting the distance between the arytenoid cartilages.
  • Vocalis muscles increase the thickness of the chords changing the tone.
  • Thyroarytenoid muscles - sphincter of vestibule, narrowing the laryngeal inlet.


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 folds apart (abduct) will cause difficulty breathing. Bilateral injury to the recurrent laryngeal nerve would cause this condition. It is also worth noting that all muscles are innervated by the recurrent laryngeal branch of the vagus except the cricothyroid muscle, which is innervated by the external laryngeal branch of the superior laryngeal nerve (a branch of the vagus).

Extrinsic muscles associated with the larynx

  • Thyrohyoid muscle
    Thyrohyoid muscle
    The Thyrohyoid muscle is a small, quadrilateral muscle appearing like an upward continuation of the Sternothyreoideus. It belongs to the infrahyoid muscles group....

    s
  • Sternothyroid muscle
    Sternothyroid muscle
    The Sternothyreoideus is shorter and wider than the Sternohyoideus, beneath which it is situated.It arises from the posterior surface of the manubrium sterni, below the origin of the Sternohyoideus, and from the edge of the cartilage of the first rib, and sometimes that of the second rib, it is...

    s
  • Omohyoid muscle
    Omohyoid muscle
    The omohyoid muscle is a muscle at the front of the neck that consists of two bellies separated by an intermediate tendon. It belongs to the group of infrahyoid muscles...

    s
  • Inferior constrictor muscles
  • Digastric
  • Stylohyoid
  • Mylohyoid
    Mylohyoid muscle
    The mylohyoid muscle is a muscle running from the mandible to the hyoid bone, forming the floor of the oral cavity. It is named for its two attachments, with the prefix "mylo" coming from the Greek word for "molar". These muscles are mesodermal in origin...

  • Geniohyoid
  • Hyoglossus
    Hyoglossus
    The Hyoglossus, thin and quadrilateral, arises from the side of the body and from the whole length of the greater cornu of the hyoid bone, and passes almost vertically upward to enter the side of the tongue, between the Styloglossus and Longitudinalis inferior....


Descended larynx


In infant humans and most animals, 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
Marine mammal
Marine mammals, which include seals, whales, dolphins, and walruses, form a diverse group of 128 species that rely on the ocean for their existence. They do not represent a distinct biological grouping, but rather are unified by their reliance on the marine environment for feeding. The level of...

, large deer
Deer
Deer are the ruminant mammals forming the family Cervidae. Species in the Cervidae family include white-tailed deer, elk, moose, red deer, reindeer, fallow deer, roe deer and chital. Male deer of all species and female reindeer grow and shed new antlers each year...

, and adult humans have descended larynges. Adult humans cannot raise the larynx enough to directly couple it to the nasal passage. Despite its presence in deer
Deer
Deer are the ruminant mammals forming the family Cervidae. Species in the Cervidae family include white-tailed deer, elk, moose, red deer, reindeer, fallow deer, roe deer and chital. Male deer of all species and female reindeer grow and shed new antlers each year...

, proponents of the aquatic ape hypothesis
Aquatic ape hypothesis
The aquatic ape hypothesis is an alternative explanation of some characteristics of human evolution which hypothesizes that the common ancestors of modern humans spent a period of time adapting to life in a partially aquatic environment. The hypothesis is based on differences between humans and...

 claim that the similarity between the descended larynx in humans and aquatic mammals supports their theory.

Some anthropologists, such as Jeffrey Laitman
Jeffrey Laitman
Jeffrey Todd Laitman, Ph.D. is an American anatomist and physical anthropologist whose science has combined experimental, comparative, and paleontological studies to understand the development and evolution of the human upper respiratory and vocal tract regions...

, 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
Language
Language may refer either to the specifically human capacity for acquiring and using complex systems of communication, or to a specific instance of such a system of complex communication...

, while others cite the presence of descended larynges in non-linguistic animals, as well as the ubiquity of nonverbal communication
Nonverbal communication
Nonverbal communication is usually understood as the process of communication through sending and receiving wordless messages. Messages can be communicated through gestures and touch , by body language or posture, by facial expression and eye contact...

 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. Larynx transplant
Organ transplant
Organ transplantation is the moving of an organ from one body to another or from a donor site on the patient's own body, for the purpose of replacing the recipient's damaged or absent organ. The emerging field of regenerative medicine is allowing scientists and engineers to create organs to be...

 is a rare procedure. The world's first successful operation took place in 1998 at the Cleveland Clinic
Cleveland Clinic
The Cleveland Clinic is a multispecialty academic medical center located in Cleveland, Ohio, United States. The Cleveland Clinic is currently regarded as one of the top 4 hospitals in the United States as rated by U.S. News & World Report...

, and the second took place in October 2010 at the University of California Medical Center in Sacramento.
  • 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
    Presbylarynx
    The 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...

     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 folds is found on laryngoscopy.

  • Ulcers
    Peptic ulcer
    A peptic ulcer, also known as PUD or peptic ulcer disease, is the most common ulcer of an area of the gastrointestinal tract that is usually acidic and thus extremely painful. It is defined as mucosal erosions equal to or greater than 0.5 cm...

     may be caused by the prolonged presence of an endotracheal tube.

  • Polyps
    Polyp (medicine)
    A polyp is an abnormal growth of tissue projecting from a mucous membrane. If it is attached to the surface by a narrow elongated stalk, it is said to be pedunculated. If no stalk is present, it is said to be sessile. Polyps are commonly found in the colon, stomach, nose, sinus, urinary bladder...

     and nodules
    Vocal fold nodule
    A vocal cord nodule is a mass of tissue that grows on the vocal folds . Typically, this mass will appear on the junction of the anterior and middle two-thirds of the vocal fold, where contact is most forceful....

     are small bumps on the vocal folds caused by prolonged exposure to cigarette
    Cigarette
    A cigarette is a small roll of finely cut tobacco leaves wrapped in a cylinder of thin paper for smoking. The cigarette is ignited at one end and allowed to smoulder; its smoke is inhaled from the other end, which is held in or to the mouth and in some cases a cigarette holder may be used as well...

     smoke and vocal misuse, respectively.

  • Two related types of cancer of the larynx
    Cancer of the larynx
    Laryngeal cancer may also be called cancer of the larynx or laryngeal carcinoma. Most laryngeal cancers are squamous cell carcinomas, reflecting their origin from the squamous cells which form the majority of the laryngeal epithelium....

    , namely squamous cell carcinoma
    Squamous cell carcinoma
    Squamous cell carcinoma , occasionally rendered as "squamous-cell carcinoma", is a histologically distinct form of cancer. It arises from the uncontrolled multiplication of malignant cells deriving from epithelium, or showing particular cytological or tissue architectural characteristics of...

     and verrucous carcinoma
    Verrucous carcinoma
    Verrucous carcinoma is an uncommon variant of squamous cell carcinoma. This form of cancer is often seen in those who chew tobacco or use snuff orally, so much so that it is sometimes referred to as "Snuff dipper's cancer."Most patients with verrucous carcinoma have a good prognosis...

    , are strongly associated with repeated exposure to cigarette smoke and alcohol.

  • Vocal cord paresis
    Vocal cord paresis
    Vocal cord paresis is weakness of one or both vocal folds. Symptoms of paresis include hoarseness; vocal fatigue; mild to severe reduction in vocal volume; pain in the throat when speaking; shortness of breath; aspiration with frequent resultant coughing, and in extreme cases may cause death...

     is weakness of one or both vocal folds that can greatly impact daily life.

  • Idiopathic laryngeal spasm
    Laryngospasm
    In medicine, laryngospasm is an uncontrolled/involuntary muscular contraction of the laryngeal cords. The condition typically lasts less than 60 seconds, and causes a partial blocking of breathing in, while breathing out remains easier. It may be triggered when the vocal cords or the area of the...

    .

  • Laryngopharyngeal reflux
    Laryngopharyngeal reflux
    Laryngopharyngeal reflux , also extraesophageal reflux disease refers to retrograde flow of gastric contents to the upper aero-digestive tract, which causes a variety of symptoms, such as cough, hoarseness, and asthma, among others.Although heartburn is a primary symptom among people with...

     is a condition in which acid from the stomach irritates and burns the larynx. Similar damage can occur with gastroesophageal reflux disease
    Gastroesophageal reflux disease
    Gastroesophageal reflux disease , gastro-oesophageal reflux disease , gastric reflux disease, or acid reflux disease is chronic symptoms or mucosal damage caused by stomach acid coming up from the stomach into the esophagus...

     (GERD).

  • Laryngomalacia
    Laryngomalacia
    Laryngomalacia is a very common condition of infancy, in which the soft, immature cartilage of the upper larynx collapses inward during inhalation, causing airway obstruction. It can also be seen in older patients, especially those with neuromuscular conditions resulting in weakness of the...

     is a very common condition of infancy, in which the soft, immature cartilage of the upper larynx collapses inward during inhalation, causing airway obstruction.

  • Laryngeal perichondritis, the inflammation of the perichondrium
    Perichondrium
    The perichondrium is a layer of dense irregular connective tissue which surrounds the cartilage of developing bone. It consists of two separate layers: an outer fibrous layer and inner chondrogenic layer. The fibrous layer contains fibroblasts, which produce collagenous fibers. The chondrogenic...

     of laryngeal cartilages, causing airway obstruction.

Cartilages


There are nine cartilages, three unpaired and three paired, that support the mammalian larynx and form its skeleton. The unpaired cartilages of the larynx are the thyroid
Thyroid cartilage
The thyroid cartilage is the largest of the nine cartilages that make up the laryngeal skeleton, the cartilage structure in and around the trachea that contains the larynx....

, cricoid and epiglottis
Epiglottis
The epiglottis is a flap that is made of elastic cartilage tissue covered with a mucous membrane, attached to the entrance of the larynx. It projects obliquely upwards behind the tongue and the hyoid bone, pointing dorsally. The term, like tonsils, is often incorrectly used to refer to the uvula...

. The paired cartilages of the larynx are the arytenoids
Arytenoid cartilage
The arytenoid cartilages are a pair of small three-sided pyramids which form part of the larynx, to which the vocal folds are attached...

, corniculate, and the cuneiforms.
  • Thyroid Cartilage
    Thyroid cartilage
    The thyroid cartilage is the largest of the nine cartilages that make up the laryngeal skeleton, the cartilage structure in and around the trachea that contains the larynx....

    :
    This forms the Adam's apple. It is usually larger in males than in females. The thyrohyoid membrane is a ligament associated with the thyroid cartilage that connects the thyroid cartilage with the hyoid bone.

  • Cricoid cartilage: A ring of hyaline cartilage that forms the inferior wall of the larynx. It is attached to the top of trachea.

  • Epiglottis
    Epiglottis
    The epiglottis is a flap that is made of elastic cartilage tissue covered with a mucous membrane, attached to the entrance of the larynx. It projects obliquely upwards behind the tongue and the hyoid bone, pointing dorsally. The term, like tonsils, is often incorrectly used to refer to the uvula...

    :
    A large, spoon-shaped piece of elastic cartilage. During swallowing
    Swallowing
    Swallowing, known scientifically as deglutition, is the process in the human or animal body that makes something pass from the mouth, to the pharynx, and into the esophagus, while shutting the epiglottis. If this fails and the object goes through the trachea, then choking or pulmonary aspiration...

    , the pharynx and larynx rise. Elevation of the pharynx widens it to receive food and drink; elevation of the larynx causes the epiglottis to move down and form a lid over the glottis, closing it off.

  • Paired Arytenoid Cartilage
    Arytenoid cartilage
    The arytenoid cartilages are a pair of small three-sided pyramids which form part of the larynx, to which the vocal folds are attached...

    :
    Of the paired cartilages, the arytenoid cartilages are the most important because they influence the position and tension of the vocal folds. These are triangular pieces of mostly hyaline cartilage located at the posterosuperior border of the cricoid cartilage.

  • Paired Corniculate Cartilage
    Corniculate cartilages
    The corniculate cartilages are two small conical nodules consisting of yellow elastic cartilage, which articulate with the summits of the arytenoid cartilages and serve to prolong them posteriorly and medially....

    :
    Horn-shaped pieces of elastic cartilage located at the apex of each arytenoid cartilage.

  • Paired Cuneiform Cartilage
    Cuneiform cartilages
    The cuneiform cartilages of the larynx are two small, elongated pieces of yellow elastic cartilage, placed one on either side, in the aryepiglottic fold, where they give rise to small whitish elevations on the surface of the mucous membrane, just in front of the arytenoid cartilages....

    :
    Club-shaped pieces of elastic cartilage located anterior to the corniculate cartilages.

Non-mammalian larynges


Most tetrapod
Tetrapod
Tetrapods are vertebrate animals having four limbs. Amphibians, reptiles, birds and mammals are all tetrapods; even snakes and other limbless reptiles and amphibians are tetrapods by descent. The earliest tetrapods evolved from the lobe-finned fishes in the Devonian...

 species possess a larynx, but its structure is typically simpler than that found in mammals. The cartilages surrounding the larynx are apparently a remnant of the original gill arches in fish, and are a common feature, but not all are always present. For example, the thyroid cartilage is found only in mammals. Similarly, only mammals possess a true epiglottis, although a flap of non-cartilagenous mucosa is found in a similar position in many other groups. In modern amphibians, the laryngeal skeleton is considerably reduced; frog
Frog
Frogs are amphibians in the order Anura , formerly referred to as Salientia . Most frogs are characterized by a short body, webbed digits , protruding eyes and the absence of a tail...

s have only the cricoid and arytenoid cartilages, while salamander
Salamander
Salamander is a common name of approximately 500 species of amphibians. They are typically characterized by a superficially lizard-like appearance, with their slender bodies, short noses, and long tails. All known fossils and extinct species fall under the order Caudata, while sometimes the extant...

s possess only the arytenoids.

Vocal folds are found only in mammals, and a few lizard
Lizard
Lizards are a widespread group of squamate reptiles, with nearly 3800 species, ranging across all continents except Antarctica as well as most oceanic island chains...

s. As a result, many reptiles and amphibians are essentially voiceless; frogs use ridges in the trachea to modulate sound, while bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...

s have a separate sound-producing organ, the syrinx
Syrinx (biology)
Syrinx is the name for the vocal organ of birds. Located at the base of a bird's trachea, it produces sounds without the vocal cords of mammals. The sound is produced by vibrations of some or all of the membrana tympaniformis and the pessulus caused by air flowing through the syrinx...

.