The Larynx

The LarynxThe Larynx

Prof. Dr.Mohammed Hisham Prof. Dr.Mohammed Hisham Al-MuhtasebAl-Muhtaseb

The LarynxThe Larynx► Extends from the middle Extends from the middle

of C3 vertebra till the of C3 vertebra till the level of the lower border level of the lower border of C6 of C6

► Continue as TracheaContinue as Trachea

► Above it opens into the Above it opens into the laryngo-pharynxlaryngo-pharynx

► Suspended from the Suspended from the hyoid bone above and hyoid bone above and attached to the trachea attached to the trachea below by membranes and below by membranes and ligaments ligaments

Functions Functions

► 1. acts as an 1. acts as an open valve in open valve in respirationrespiration

► 2. Acts as a 2. Acts as a closed valve in closed valve in deglutitiondeglutition

► 3. Acts as a 3. Acts as a partially closed partially closed valve in the production of valve in the production of voicevoice

► 4. During cough it is first closed 4. During cough it is first closed and then open suddenly to and then open suddenly to release compressed airrelease compressed air

PartsParts

►1. Cartilage1. Cartilage

►2. Mucosa2. Mucosa

►3. Ligaments3. Ligaments

►4. Muscles4. Muscles

CartilageCartilage

► A. Single :A. Single : EpiglottisEpiglottis CricoidCricoid ThyroidThyroid

B. Pairs:B. Pairs: ArytenoidArytenoid Cuneiform Cuneiform CorniculateCorniculate

Cricoid cartilage Cricoid cartilage

► The most inferior of the The most inferior of the laryngeal cartilages laryngeal cartilages

► Completely encircles the Completely encircles the airway airway

► Shaped like a 'signet ring' Shaped like a 'signet ring'

► Broad Broad lamina of cricoid lamina of cricoid cartilagecartilage posterior posterior

► Much narrower Much narrower arch of arch of cricoid cartilagecricoid cartilage circling circling anteriorly. anteriorly.

Cricoid cartilageCricoid cartilage

► Posterior surface of the lamina has Posterior surface of the lamina has two oval depressions separated by a two oval depressions separated by a ridge ridge

► TheThe esophagus esophagus is attached to the is attached to the ridge ridge

► Depressions are for attachment of the Depressions are for attachment of the posterior crico-arytenoid posterior crico-arytenoid musclesmuscles..

► Has two Has two articular facetsarticular facets on each on each side side

► One facet is on the sloping One facet is on the sloping superolateral surface and articulates superolateral surface and articulates with the with the base of an arytenoid base of an arytenoid cartilage; cartilage;

► The other facet is on the lateral The other facet is on the lateral surface near its base and is for surface near its base and is for articulation with the articulation with the inferior horn of inferior horn of the thyroid cartilagethe thyroid cartilage

Thyroid cartilage Thyroid cartilage

► The largest of the The largest of the laryngeal cartilages laryngeal cartilages

► It is formed by a right It is formed by a right and a left lamina and a left lamina

► Widely separated Widely separated posteriorlyposteriorly, but , but converge and join converge and join anteriorly anteriorly

► Posterior margin of each Posterior margin of each lamina is elongated to lamina is elongated to form a form a superior hornsuperior horn and an and an inferior horninferior horn

Thyroid cartilageThyroid cartilage

► Most superior point of the site of fusion Most superior point of the site of fusion between the two laminae is the between the two laminae is the laryngeal prominencelaryngeal prominence ( ('Adam's 'Adam's appleapple') ')

► Angle between the two laminae is more Angle between the two laminae is more acute in men (90°) than in women (120°) acute in men (90°) than in women (120°)

► Superior to the laryngeal prominence, Superior to the laryngeal prominence, the the superior thyroid notchsuperior thyroid notch separates separates the two laminaethe two laminae

► Superior thyroid notch and the laryngeal Superior thyroid notch and the laryngeal prominence are prominence are palpablepalpable landmarks in landmarks in the neck the neck

► Less distinct Less distinct inferior thyroid notchinferior thyroid notch in in the midline along the base of the thyroid the midline along the base of the thyroid cartilage. cartilage.

Thyroid cartilageThyroid cartilage

► The medial surface of the inferior horn The medial surface of the inferior horn has a has a facetfacet for articulation with the for articulation with the cricoid cartilage; cricoid cartilage;

► The superior horn is connected by aThe superior horn is connected by a ligament ligament to the posterior end of the to the posterior end of the greater horn of the greater horn of the hyoid bonehyoid bone. .

► Lateral surface of lamina is marked by Lateral surface of lamina is marked by a ridge (the a ridge (the oblique lineoblique line), which ), which curves anteriorly from the base of the curves anteriorly from the base of the superior horn to the inferior margin of superior horn to the inferior margin of the lamina.the lamina.

► Ends of the oblique line are expanded Ends of the oblique line are expanded to form to form superiorsuperior and and inferior thyroid inferior thyroid tuberclestubercles

► The oblique line is a site of attachment The oblique line is a site of attachment for the for the extrinsic musclesextrinsic muscles of the of the larynx (sternothyroid, thyrohyoid, and larynx (sternothyroid, thyrohyoid, and inferior constrictor). inferior constrictor).

Epiglottis Epiglottis

► Is a 'leaf-shaped' cartilage attached Is a 'leaf-shaped' cartilage attached by its stem to the angle of the thyroid by its stem to the angle of the thyroid cartilagecartilage

► Projects posterosuperiorly from its Projects posterosuperiorly from its attachment to the thyroid cartilage. attachment to the thyroid cartilage.

► The attachment is via the The attachment is via the thyro-thyro-epiglottic ligamentepiglottic ligament in the midline in the midline between the laryngeal prominence between the laryngeal prominence and the inferior thyroid notch and the inferior thyroid notch

► The upper margin of the epiglottis is The upper margin of the epiglottis is behind the pharyngeal part of the behind the pharyngeal part of the tongue. tongue.

► The inferior half of the posterior The inferior half of the posterior surface of the epiglottis is raised surface of the epiglottis is raised slightly to form an slightly to form an epiglottic epiglottic tubercle. tubercle.

Arytenoid cartilages Arytenoid cartilages

► Two arytenoid cartilages are Two arytenoid cartilages are pyramid-shaped cartilages with pyramid-shaped cartilages with three surfaces three surfaces

► Base of arytenoid cartilageBase of arytenoid cartilage and an and an Apex of arytenoid Apex of arytenoid cartilagecartilage

► TheThe base base of arytenoid cartilage of arytenoid cartilage is concave and articulates with is concave and articulates with the facet on the superolateral the facet on the superolateral surface of the surface of the cricoid cricoid cartilagecartilage; ;

► The The apex apex of arytenoid cartilage of arytenoid cartilage articulates with a articulates with a corniculate corniculate cartilagecartilage; ;

► The The medial surfacemedial surface of each of each cartilage faces the other; cartilage faces the other;

Arytenoid cartilagesArytenoid cartilages

► The The anterolateral surfaceanterolateral surface has two depressions, has two depressions, separated by a ridge, for separated by a ridge, for muscle (vocalis)muscle (vocalis) and and ligament (vestibular ligament (vestibular ligament)ligament) attachment. attachment.

► The anterior angle of the base The anterior angle of the base of arytenoid cartilage is of arytenoid cartilage is elongated into a elongated into a vocal vocal processprocess to which the to which the vocal vocal ligamentligament is attached is attached

► The lateral angle is similarly The lateral angle is similarly elongated into a elongated into a muscular muscular processprocess for attachment of the for attachment of the posterior and lateral crico-posterior and lateral crico-arytenoid muscles. arytenoid muscles.

Corniculate and Cuneiform Corniculate and Cuneiform

► The The corniculate corniculate cartilages are two cartilages are two small conical cartilages small conical cartilages

► Bases articulate with the apices of Bases articulate with the apices of the arytenoid cartilages the arytenoid cartilages

► Their apices project posteromedially Their apices project posteromedially towards each other. towards each other.

► The The CuneiformCuneiform are two small club- are two small club-shaped cartilages shaped cartilages

► Lie anterior to the corniculate Lie anterior to the corniculate cartilages cartilages

► Suspended in the part of the Suspended in the part of the fibroelastic membrane that attaches fibroelastic membrane that attaches the arytenoid the epiglottis. the arytenoid the epiglottis.

LigamentsLigaments

Extrinsic ligamentsExtrinsic ligaments

►Thyrohyoid membrane Thyrohyoid membrane

►Hyo-epiglottic ligament Hyo-epiglottic ligament

►Cricotracheal ligament Cricotracheal ligament

Thyrohyoid membrane Thyrohyoid membrane

► Tough fibroelastic ligament Tough fibroelastic ligament that spans between the that spans between the superior margin of the thyroid superior margin of the thyroid cartilage below and the hyoid cartilage below and the hyoid bone bone

► Attached to the thyroid laminae Attached to the thyroid laminae and adjacent anterior margins and adjacent anterior margins of the superior horns of the superior horns

► Ascends medial to the greater Ascends medial to the greater horns and posterior to the body horns and posterior to the body of the hyoid bone to attach to of the hyoid bone to attach to the superior margins of these the superior margins of these structures. structures.

► An An apertureaperture in the lateral part in the lateral part of the thyrohyoid membrane on of the thyrohyoid membrane on each side is for the each side is for the superior superior laryngeal arteries, nerves, laryngeal arteries, nerves, and lymphaticsand lymphatics

Thyrohyoid membrane Thyrohyoid membrane

► The posterior borders of The posterior borders of the thyrohyoid membrane the thyrohyoid membrane are thickened to form the are thickened to form the lateral thyrohyoid lateral thyrohyoid ligamentsligaments. .

► Also thickened anteriorly in Also thickened anteriorly in the midline to form the the midline to form the median thyrohyoid median thyrohyoid ligamentligament. .

► Occasionally, there is a Occasionally, there is a small cartilage (small cartilage (triticeal triticeal cartilagecartilage) in each lateral ) in each lateral thyrohyoid ligament. thyrohyoid ligament.

Extrinsic ligamentsExtrinsic ligaments

► Cricotracheal Cricotracheal ligamentligament runs from the runs from the lower border of the lower border of the cricoid cartilage to the cricoid cartilage to the adjacent upper border adjacent upper border of the first tracheal of the first tracheal cartilage.cartilage.

► The hyo-epiglottic The hyo-epiglottic ligamentligament extends from extends from the midline of the the midline of the epiglottis, epiglottis, anterosuperiorly to the anterosuperiorly to the body of the hyoid bone. body of the hyoid bone.

Intrinsic ligaments Intrinsic ligaments

►The fibro-elastic membrane of larynx The fibro-elastic membrane of larynx links together the cartilages and links together the cartilages and completes the architectural framework completes the architectural framework of the laryngeal cavity of the laryngeal cavity

► It is composed of two parts-a lower It is composed of two parts-a lower cricothyroid ligamentcricothyroid ligament and an upper and an upper quadrangular membrane.quadrangular membrane.

Cricothyroid ligamentCricothyroid ligament

► Cricovocal membrane or cricothyroid Cricovocal membrane or cricothyroid membranemembrane

► Attached to the arch of cricoid cartilage and Attached to the arch of cricoid cartilage and extends superiorly extends superiorly

► End in a End in a free upper marginfree upper margin within the space within the space enclosed by the thyroid cartilage enclosed by the thyroid cartilage

► Upper free margin attaches: Upper free margin attaches: ► AnteriorlyAnteriorly to the to the thyroid cartilage;thyroid cartilage; ► PosteriorlyPosteriorly to the to the vocal processesvocal processes of the of the

arytenoid cartilages.arytenoid cartilages.

► The free margin is thickened to form the The free margin is thickened to form the vocal vocal ligamentligament, which is under the , which is under the vocal foldvocal fold ( (truetrue ''vocal cordvocal cord') of the larynx. ') of the larynx.

► The cricothyroid ligament is also thickened The cricothyroid ligament is also thickened anteriorly to form a anteriorly to form a median cricothyroid median cricothyroid ligamentligament

► In emergency situations, the median In emergency situations, the median cricothyroid ligament can be perforated to cricothyroid ligament can be perforated to establish an airwayestablish an airway

Quadrangular membrane Quadrangular membrane

► Runs between the lateral margin Runs between the lateral margin of the epiglottis and the of the epiglottis and the anterolateral surface of the anterolateral surface of the arytenoid cartilage arytenoid cartilage

► Attached to the corniculate Attached to the corniculate cartilage cartilage

► Free upper margin and a free Free upper margin and a free lower margin lower margin

► Free lower marginFree lower margin is is thickened to form the thickened to form the vestibular ligamentvestibular ligament under the under the vestibular foldvestibular fold ( (falsefalse ' 'vocal vocal cordcord') ')

Quadrangular membraneQuadrangular membrane

►Vestibular ligament Vestibular ligament is separated from is separated from the vocal ligament the vocal ligament below by a gap below by a gap

►When viewed from When viewed from above the vestibular above the vestibular ligament is ligament is laterallateral to the vocal to the vocal ligamentligament

Cartilage and LigamentsCartilage and Ligaments

Laryngeal jointsLaryngeal joints

Cricothyroid joints Cricothyroid joints

► Between the inferior horns of the Between the inferior horns of the thyroid cartilage and the cricoid thyroid cartilage and the cricoid cartilage, are cartilage, are synovial synovial

► Surrounded by a capsule and is Surrounded by a capsule and is reinforced by associated ligaments reinforced by associated ligaments

► Enable the thyroid cartilage to Enable the thyroid cartilage to move move forward and tilt forward and tilt downwardsdownwards on the cricoid on the cricoid cartilagecartilage

► Forward movement and downward Forward movement and downward rotation of the thyroid cartilage rotation of the thyroid cartilage effectively effectively lengthens and puts lengthens and puts tension on the vocal ligaments tension on the vocal ligaments

Crico-arytenoid joints Crico-arytenoid joints

► Between articular facets on Between articular facets on the superolateral surfaces of the superolateral surfaces of the cricoid cartilage and the the cricoid cartilage and the bases of the arytenoid bases of the arytenoid cartilages cartilages

► Enable the arytenoid Enable the arytenoid cartilages to cartilages to slide away or slide away or towards each other and to towards each other and to rotate rotate

► The vocal processes The vocal processes pivot pivot either towards or away either towards or away from the midline. from the midline.

► These movements These movements abduct abduct and adduct the vocal and adduct the vocal ligamentsligaments

Cavity of the larynx Cavity of the larynx

Laryngeal cavityLaryngeal cavity

► The central cavity of the The central cavity of the larynx is tubular in shape larynx is tubular in shape and is lined by mucosa and is lined by mucosa

► Support is provided by the Support is provided by the fibro-elastic membrane of fibro-elastic membrane of larynx and by the larynx and by the cartilages to which it is cartilages to which it is attached. attached.

► The superior aperture of The superior aperture of the cavity the cavity (laryngeal (laryngeal inlet)inlet) opens into the opens into the anterior aspect of the anterior aspect of the pharynx just below and pharynx just below and posterior to the tongue posterior to the tongue

► laryngeal inlet is laryngeal inlet is obliqueoblique and points and points posterosuperiorlyposterosuperiorly

laryngeal inletlaryngeal inlet

► Anterior border is formed Anterior border is formed by mucosa covering the by mucosa covering the superior margin of the superior margin of the epiglottis epiglottis

► Lateral borders are formed Lateral borders are formed by mucosal folds by mucosal folds ((aryepiglottic foldsaryepiglottic folds), ),

► Posterior border in the Posterior border in the midline is formed by a midline is formed by a mucosal fold that forms a mucosal fold that forms a depression depression ((interarytenoid notchinterarytenoid notch) ) between the two between the two corniculate tubercles corniculate tubercles

► Aryepiglottic foldsAryepiglottic folds

► Enclose the superior Enclose the superior margins of the margins of the quadrangular quadrangular membranes and membranes and adjacent soft tissues adjacent soft tissues

► Two tubercles on the Two tubercles on the more posterolateral more posterolateral margin side mark the margin side mark the positions of the positions of the underlying underlying cuneiform cuneiform and corniculateand corniculate cartilages; cartilages;

Inferior openingInferior opening

► Inferior opening of the Inferior opening of the laryngeal cavity is laryngeal cavity is continuous with the lumen continuous with the lumen of the trachea of the trachea

► Completely encircled by Completely encircled by the cricoid cartilage the cricoid cartilage

► Horizontal in position unlike Horizontal in position unlike the laryngeal inletthe laryngeal inlet

► The inferior opening is The inferior opening is continuously open whereas continuously open whereas the laryngeal inlet can be the laryngeal inlet can be closed by downward closed by downward movement of the epiglottis movement of the epiglottis

Division into three major Division into three major regions regions

► The The vestibular and vocal vestibular and vocal foldsfolds, divide it into three , divide it into three major regionsmajor regions-the -the vestibule, vestibule, a a middle middle chamber, chamber, and theand the infraglottic cavity infraglottic cavity

► The The vestibulevestibule is the upper is the upper chamber of the laryngeal chamber of the laryngeal cavity between the cavity between the laryngeal inlet and the laryngeal inlet and the vestibular foldsvestibular folds

► Vestibular folds enclose the Vestibular folds enclose the vestibular ligaments and vestibular ligaments and associated soft tissues; associated soft tissues;

Division into three major Division into three major regionsregions

► The The middle partmiddle part of the of the laryngeal cavity is very laryngeal cavity is very thin and is between the thin and is between the vestibular folds above and vestibular folds above and the vocal folds below the vocal folds below

► Vocal folds enclose the Vocal folds enclose the vocal ligaments and vocal ligaments and related soft tissues below. related soft tissues below.

► The The infraglottic spaceinfraglottic space is is the most inferior chamber the most inferior chamber and is between the vocal and is between the vocal folds and the inferior folds and the inferior opening of the larynx; opening of the larynx;

Vocal FoldsVocal Folds► Consist of :Consist of :► Vocal ligamentVocal ligament

► Mucous membrane (stratified Mucous membrane (stratified squamous)squamous)

► Vocalis muscleVocalis muscle

► No submucosaNo submucosa

► No blood vessels (white in color)No blood vessels (white in color)

► On each side extend between the On each side extend between the vocal process of the arytenoid and vocal process of the arytenoid and the back of the anterior lamina of the back of the anterior lamina of thyroid.thyroid.

► Longer in male which cause the Longer in male which cause the difference of the pitch of the voice difference of the pitch of the voice between gendersbetween genders

Vestibular foldsVestibular folds

► False vocal cordsFalse vocal cords

► Vestibular folds enclose Vestibular folds enclose the vestibular ligaments the vestibular ligaments and associated soft and associated soft tissuestissues

► Vascularised (red in color)Vascularised (red in color)

► Fixed and not movable Fixed and not movable unlike the vocal cordunlike the vocal cord

► Superior to the vocal cordSuperior to the vocal cord

Laryngeal ventricles and Laryngeal ventricles and saccules saccules

► On each side, the mucosa of On each side, the mucosa of the middle cavity bulges the middle cavity bulges laterally through the gap laterally through the gap between the vestibular and between the vestibular and vocal ligaments to produce a vocal ligaments to produce a laryngeal ventriclelaryngeal ventricle

► Tubular extension of each Tubular extension of each ventricle (laryngeal saccule) ventricle (laryngeal saccule) projects anterosuperiorly projects anterosuperiorly between the vestibular fold between the vestibular fold and thyroid cartilage and thyroid cartilage

► Within the walls of these Within the walls of these laryngeal saccules are laryngeal saccules are numerous mucous glands. numerous mucous glands.

► MucusMucus secreted into the secreted into the saccules saccules lubricates the lubricates the vocal foldsvocal folds. .

Rima vestibuli and rima Rima vestibuli and rima glottidis glottidis

► Rima vestibuliRima vestibuli is a triangular- is a triangular-shaped opening between the shaped opening between the two adjacent two adjacent vestibular foldsvestibular folds at the entrance to the middle at the entrance to the middle chamber chamber

► Apex of the opening is anterior Apex of the opening is anterior and its base is posteriorand its base is posterior

► The The Rima glottidis Rima glottidis is formed is formed by the by the vocal folds (true vocal vocal folds (true vocal cords)cords) and adjacent mucosa- and adjacent mucosa-covered parts of the arytenoid covered parts of the arytenoid cartilages cartilages

Rima vestibuli and rima Rima vestibuli and rima glottidisglottidis

► Rima glottidis Rima glottidis opening opening separates the middle chamber separates the middle chamber above from the infraglottic above from the infraglottic cavity cavity

► The base of it is formed by the The base of it is formed by the fold of mucosa (interarytenoid fold of mucosa (interarytenoid fold) at the bottom of the fold) at the bottom of the interarytenoid notch interarytenoid notch

► Rima glottis is the narrowest Rima glottis is the narrowest part of the laryngeal cavitypart of the laryngeal cavity

► Both the rima glottidis and the Both the rima glottidis and the rima vestibuli can be opened rima vestibuli can be opened and closed by movement of and closed by movement of the arytenoid cartilages and the arytenoid cartilages and associated membranes. associated membranes.

MusclesMuscles

Intrinsic muscles Intrinsic muscles

►Adjust tension in the vocal ligaments, Adjust tension in the vocal ligaments,

►Open and close the rima glottidis, Open and close the rima glottidis,

►Control the inner dimensions of the Control the inner dimensions of the vestibule, vestibule,

►Close the rima vestibuli Close the rima vestibuli

Cricothyroid muscles Cricothyroid muscles

► Fan-shaped muscles Fan-shaped muscles

► Attached to the anterolateral Attached to the anterolateral surfaces of the cricoid surfaces of the cricoid cartilage and expand cartilage and expand superiorly and posteriorly to superiorly and posteriorly to attach to the thyroid cartilageattach to the thyroid cartilage

► Each muscle has an oblique Each muscle has an oblique part and a straight part: part and a straight part:

► The The oblique partoblique part runs in a runs in a posterior direction from the posterior direction from the arch of the cricoid to the arch of the cricoid to the inferior horn of the thyroid inferior horn of the thyroid cartilage cartilage

► The The straight partstraight part runs more runs more vertically from the arch of the vertically from the arch of the cricoid to the posteroinferior cricoid to the posteroinferior margin of the thyroid lamina margin of the thyroid lamina

Cricothyroid musclesCricothyroid muscles► Pull the thyroid cartilage Pull the thyroid cartilage

forward forward and and rotaterotate it down it down relative to the cricoid cartilage relative to the cricoid cartilage

► These actions These actions Tenses vocal Tenses vocal cords cords

► Are the only intrinsic muscles Are the only intrinsic muscles innervated by the innervated by the superior superior laryngeal brancheslaryngeal branches of the of the vagus nerves vagus nerves

► All other intrinsic muscles are All other intrinsic muscles are innervated by the innervated by the recurrent recurrent laryngeal brancheslaryngeal branches of the of the vagus nerves vagus nerves

Posterior crico-arytenoid Posterior crico-arytenoid muscles muscles

► There is a right and a left There is a right and a left posterior crico-arytenoidposterior crico-arytenoid

► The fibers of each muscle The fibers of each muscle originate from the Back of originate from the Back of cricoid cartilage , and run cricoid cartilage , and run superiorly and laterally to superiorly and laterally to the muscular processes of the muscular processes of the arytenoid cartilage the arytenoid cartilage

► Abducts the vocal cordsAbducts the vocal cords by rotating arytenoid by rotating arytenoid cartilage cartilage

► Innervated by the recurrent Innervated by the recurrent laryngeal branches of the laryngeal branches of the vagus nerves vagus nerves

Lateral crico-arytenoid Lateral crico-arytenoid muscles muscles

► Muscle on each side Muscle on each side originates from the Upper originates from the Upper border of cricoid cartilage , border of cricoid cartilage , and runs posteriorly and and runs posteriorly and superiorly to insert on the superiorly to insert on the muscular process of the muscular process of the arytenoidarytenoid

► Adducts the vocal cordsAdducts the vocal cords by internally rotating by internally rotating arytenoid cartilage arytenoid cartilage

► Innervated by the Innervated by the recurrent laryngeal recurrent laryngeal

Transverse arytenoid Transverse arytenoid

► Originates from Back Originates from Back and medial surface of and medial surface of arytenoid cartilage and arytenoid cartilage and insert in the Back and insert in the Back and medial surface of medial surface of opposite arytenoid opposite arytenoid cartilagecartilage

► Closes posterior part Closes posterior part of rima glottidisof rima glottidis by by approximating approximating arytenoid cartilages arytenoid cartilages

► Recurrent laryngeal Recurrent laryngeal nerve nerve

Thyroarytenoid (vocalis) Thyroarytenoid (vocalis)

► From the Inner From the Inner surface of thyroid surface of thyroid cartilage to the cartilage to the Arytenoid cartilageArytenoid cartilage

►Relaxes vocal Relaxes vocal cords cords


Oblique arytenoidOblique arytenoid

► From the Muscular From the Muscular process of arytenoid process of arytenoid cartilage to the Apex of cartilage to the Apex of opposite arytenoid opposite arytenoid cartilagecartilage

► Narrows the inletNarrows the inlet by by bringing the aryepiglottic bringing the aryepiglottic folds together folds together


Thyroepiglottic (aryepiglottic Thyroepiglottic (aryepiglottic muscles)muscles)

► From the Medial surface From the Medial surface of thyroid cartilage to of thyroid cartilage to the Lateral margin of the Lateral margin of epiglottis and epiglottis and aryepiglottic foldaryepiglottic fold

► Widens the inletWidens the inlet by by pulling the aryepiglottic pulling the aryepiglottic folds apart folds apart


Extrinsic musclesExtrinsic muscles

► Elevators of the larynx:Elevators of the larynx:► 1. Digastric muscle1. Digastric muscle► 2. Stylohyoid2. Stylohyoid► 3. Myelohyoid3. Myelohyoid► 4. Geniohyoid4. Geniohyoid

► The larynx moves up in swallowing by these muscles The larynx moves up in swallowing by these muscles assisted by :assisted by :

► Stylopharngeus, Salpingo-pharngeus, And Palatopharngeus.Stylopharngeus, Salpingo-pharngeus, And Palatopharngeus.

► Depressors of the larynx :Depressors of the larynx :► 1. Sternothyroid1. Sternothyroid► 2. Sternohyoid2. Sternohyoid► 3. Omohyoid3. Omohyoid

Muscles and CavityMuscles and Cavity

Function of the larynxFunction of the larynx

RespirationRespiration

► During quiet respiration, the During quiet respiration, the laryngeal inlet, vestibule, laryngeal inlet, vestibule, rima vestibuli, and rima rima vestibuli, and rima glottidis are glottidis are open open

► During forced inspiration During forced inspiration the arytenoid cartilages are the arytenoid cartilages are rotated laterallyrotated laterally, mainly , mainly by the action of the by the action of the posterior crico-arytenoid posterior crico-arytenoid musclesmuscles..

► As a result, the vocal folds As a result, the vocal folds are are abductedabducted, and the , and the rima glottidis widensrima glottidis widens into into a rhomboid shape, a rhomboid shape, effectively effectively increases the increases the diameter of the diameter of the laryngeal airwaylaryngeal airway. .

Phonation Phonation

► When phonating, the When phonating, the arytenoid cartilages and arytenoid cartilages and vocal folds are vocal folds are adductedadducted and air is forced through and air is forced through the the closed rima glottidis closed rima glottidis

► This action causes the vocal This action causes the vocal folds to folds to vibratevibrate against against each other and produce each other and produce sounds sounds

► Can then be modified by Can then be modified by the upper parts of the the upper parts of the airway and oral cavity airway and oral cavity

► TensionTension in the vocal folds in the vocal folds can be adjusted by the can be adjusted by the vocalis and cricothyroid vocalis and cricothyroid muscles. muscles.

Effort closure Effort closure

► Effort closure of the larynx Effort closure of the larynx occurs when air is retained occurs when air is retained in the thoracic cavity to in the thoracic cavity to stabilize the trunkstabilize the trunk

► For example during heavy For example during heavy lifting, or as part of the lifting, or as part of the mechanism for increasing mechanism for increasing intra-abdominal pressure intra-abdominal pressure

► The rima glottidis is The rima glottidis is completely closedcompletely closed, as is , as is the rima vestibuli and lower the rima vestibuli and lower parts of the vestibule parts of the vestibule

► The result is to completely The result is to completely and and forcefully shut the forcefully shut the airwayairway. .

Swallowing Swallowing

► During swallowing, the rima During swallowing, the rima glottidis, the rima vestibuli, and glottidis, the rima vestibuli, and vestibule are vestibule are closedclosed and the and the laryngeal inlet is narrowed laryngeal inlet is narrowed

► The larynx moves The larynx moves up and forwardup and forward

► This action causes the This action causes the epiglottisepiglottis to to swingswing downward downward to effectively to effectively narrow or close the laryngeal narrow or close the laryngeal inletinlet

► The up and forward movement of The up and forward movement of the larynx also the larynx also opens the opens the esophagus esophagus

► All these actions together All these actions together prevent prevent solids and liquids from entry solids and liquids from entry into the airway into the airway

Blood SupplyBlood Supply

Arteries Arteries

► The major blood supply to The major blood supply to the larynx is by the the larynx is by the superior and inferior superior and inferior laryngeal arteries laryngeal arteries

► The The superior laryngeal superior laryngeal arteryartery originates from the originates from the superior thyroid branch of superior thyroid branch of the external carotid artery, the external carotid artery,

► Accompanies the internal Accompanies the internal branch of the superior branch of the superior laryngeal nerve through laryngeal nerve through the thyrohyoid membrane the thyrohyoid membrane to reach the larynx. to reach the larynx.

ArteriesArteries

► The The inferior laryngeal inferior laryngeal arteryartery originates from the originates from the inferior thyroid branch of inferior thyroid branch of the thyrocervical trunk of the thyrocervical trunk of the subclavian arterythe subclavian artery

► Together with the Together with the recurrent laryngeal nerve, recurrent laryngeal nerve, ascends in the groove ascends in the groove between the esophagus between the esophagus and tracheaand trachea

► It enters the larynx by It enters the larynx by passing deep to the margin passing deep to the margin of the inferior constrictor of the inferior constrictor muscle of the pharynx; muscle of the pharynx;

Veins Veins

► Veins draining the Veins draining the larynx accompany the larynx accompany the arteries: arteries:

► Superior laryngeal Superior laryngeal veinsveins drain into drain into superior thyroid veins, superior thyroid veins, which in turn drain into which in turn drain into the internal jugular the internal jugular veinsveins

► Inferior laryngeal Inferior laryngeal veinsveins drain into inferior drain into inferior thyroid veins, which thyroid veins, which drain into the left drain into the left brachiocephalic veins. brachiocephalic veins.

Lymphatics Lymphatics

► Lymphatics drain regions above and below the Lymphatics drain regions above and below the vocal folds: vocal folds:

► Those above the vocal folds follow the superior Those above the vocal folds follow the superior laryngeal artery and terminate in deep cervical laryngeal artery and terminate in deep cervical nodes nodes

► Those below the vocal folds drain into deep nodes Those below the vocal folds drain into deep nodes associated with the inferior thyroid artery associated with the inferior thyroid artery

► Or with nodes associated with the front of the Or with nodes associated with the front of the cricothyroid ligament or upper trachea. cricothyroid ligament or upper trachea.

InnervationsInnervations

Superior laryngeal nerves Superior laryngeal nerves

► The The superior laryngeal superior laryngeal nervesnerves originate from the originate from the inferior vagal ganglia high in the inferior vagal ganglia high in the neck neck

► They descend medial to the They descend medial to the internal carotid artery and internal carotid artery and divide into divide into internalinternal and and external branchesexternal branches above the above the hyoid bone hyoid bone

► The external branch (The external branch (external external laryngeal nervelaryngeal nerve) descends ) descends along the lateral wall of the along the lateral wall of the pharynx to supply the inferior pharynx to supply the inferior constrictor of the pharynx and constrictor of the pharynx and ends by supplying the ends by supplying the cricothyroid muscle; cricothyroid muscle;

Superior laryngeal nervesSuperior laryngeal nerves

► The The internal internal laryngeal nervelaryngeal nerve passes anteroinferiorly passes anteroinferiorly to penetrate the to penetrate the thyrohyoid membranethyrohyoid membrane

► Internal nerve is mainly Internal nerve is mainly sensorysensory and supplies and supplies the laryngeal cavity the laryngeal cavity down to down to the level of the level of the vocal folds. the vocal folds.

Recurrent laryngeal nerves Recurrent laryngeal nerves

► The recurrent laryngeal The recurrent laryngeal nerves are: nerves are:

► Sensory to the Sensory to the laryngeal cavity laryngeal cavity below below the level of the vocal the level of the vocal foldsfolds; ;

► Motor to all intrinsic Motor to all intrinsic muscles of the larynx muscles of the larynx except for the except for the cricothyroidcricothyroid..

Recurrent laryngeal nervesRecurrent laryngeal nerves

► The The leftleft recurrent recurrent laryngeal nerve originates laryngeal nerve originates in thein the thorax thorax whereas the whereas the rightright recurrent laryngeal recurrent laryngeal nerve originates in the nerve originates in the root of the neck root of the neck

► Both nerves generally Both nerves generally ascend in the neck in the ascend in the neck in the groove between the groove between the esophagus and trachea esophagus and trachea

► Enter the larynx deep to Enter the larynx deep to the margin of the inferior the margin of the inferior constrictor constrictor

Relations of the larynxRelations of the larynx

► On each side :On each side :► Carotid sheath Carotid sheath

(contents), and lateral (contents), and lateral lobe of the thyroid lobe of the thyroid glandgland

► Posterior:Posterior:► Pharynx and the right Pharynx and the right

recurrent laryngeal recurrent laryngeal nervenerve

► Anterior:Anterior:► Skin, fascia and its Skin, fascia and its

contents, 4 infra-hyoid contents, 4 infra-hyoid musclesmuscles

Clinical notesClinical notes

ThyroidoctomyThyroidoctomy

► Sectioning of the Sectioning of the external laryngealexternal laryngeal nerve nerve might happen in thyroidoctomymight happen in thyroidoctomy

►Due to the close relationship between the Due to the close relationship between the external laryngeal nerve and the superior external laryngeal nerve and the superior thyroid artery.thyroid artery.

► Produces Produces weakness in voiceweakness in voice since the vocal since the vocal cords cannot be tensed (criciothyroid M.).cords cannot be tensed (criciothyroid M.).

Section of the Recurrent Section of the Recurrent laryngeal nervelaryngeal nerve

► 1. Unilateral complete 1. Unilateral complete section:section:

►One vocal fold (on the One vocal fold (on the affected side) in the affected side) in the position midway between position midway between abducted and adductedabducted and adducted

► Speech not greatly Speech not greatly affected as the other vocal affected as the other vocal cord compensate for the cord compensate for the action.action.


► 2. Bilateral 2. Bilateral complete section:complete section:

► Both vocal folds in Both vocal folds in position midway position midway between abducted between abducted and adductedand adducted

► Breathing is impaired Breathing is impaired since the rima glottis since the rima glottis is partially close and is partially close and speech is lostspeech is lost


► 3. Unilateral partial 3. Unilateral partial section :section :

► This results in a greater This results in a greater degree of paralysis of the degree of paralysis of the abductor muscles than of abductor muscles than of the adductor .the adductor .

► Therefore the affected cord Therefore the affected cord is in the adducted midline is in the adducted midline positionposition

► Hoarseness of the voice Hoarseness of the voice (the other vocal fold (the other vocal fold compensates the action)compensates the action)


► 4. Bilateral partial section:4. Bilateral partial section:

► This results in bilateral paralysis This results in bilateral paralysis of the abductor muscles of the abductor muscles

► Therefore the vocal folds are Therefore the vocal folds are adducted together in the adducted together in the midlinemidline

► Acute breathlessness (Dyspnea) Acute breathlessness (Dyspnea) and stridor followand stridor follow

► Lead to suffocation so Lead to suffocation so tracheostmy is necessarytracheostmy is necessary

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The Larynx

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