Gross Anatomy

Larynx


Anatomy Tables for Today's Topic


Bones and Cartilages of the Larynx
Muscles
Nerves
Arteries
Viscera

Bones and Cartilages of the Larynx

Bone/Cartilage Structure Description Notes
hyoid a "U"-shaped bone consisting of several parts: body, 2 greater horns, 2 lesser horns the hyoid bone ossifies completely in middle life; the body articulates with the greater horns via cartilage and with the lesser horns via fibrous joints prior to ossification; an important site for muscle attachments (suprahyoid and infrahyoid muscle groups)
body the middle portion of the "U"-shaped bone the body of the hyoid bone articulates with the greater horns posteriorly
greater horn (cornu) posteriorly directed limbs of the "U"-shaped bone each greater horn articulates with the body and lesser horns anteriorly; origin of middle pharyngeal constrictor m. and hyoglossus m.
lesser horn (cornu) articulates with the greater horn at its junction with the body the inferior end of the stylohyoid ligament attaches to the lesser horn
thyroid cartilage the large anterior cartilage of the larynx; it has several parts: laminae (2), superior horns (2), inferior horns (2), oblique line, superior thyroid notch, connected above to the hyoid bone via the thyrohyoid membrane; connected below to the cricoid cartilage via the inferior horn of the thyroid cartilage; connected posteriorly: to the arytenoid cartilage via the vocal ligament and thyroarytenoid m., to the epiglottic cartilage via the thyroepiglottic ligament; it tilts anteriorly to increase the length of the vocal ligament and raise the pitch of the voice
lamina a broad flat plate of cartilage forming one side of the thyroid cartilage; two laminae fuse anteriorly in the midline to form the thyroid cartilage the laryngeal prominence is the line of fusion of the two laminae; each lamina is connected superiorly to the hyoid bone by the thyrohyoid membrane
superior horn the rounded, superior projection of the posterior border of the thyroid lamina it is connected superiorly to the greater horn of the hyoid bone by the lateral thyrohyoid ligament
inferior horn the rounded, inferior projection of the posterior border of the thyroid lamina it is connected inferiorly to the cricoid cartilage by the cricothyroid articulation (a synovial joint)
oblique line ridge which descends diagonally from superior to inferior on the lateral surface of the thyroid lamina a line of muscle attachment
laryngeal prominence the line of fusion of the thyroid laminae known to the lay person as the "Adam's apple"; the laryngeal prominence is a secondary sexual characteristic - in postpuberal males the angle of the laryngeal prominence is approximately 90¡ and in females the angle is approximately 120¡
superior thyroid notch the notch at the superior end of the laryngeal prominence it is connected to the hyoid bone by the median thyrohyoid ligament
epiglottis the superior part of the larynx epiglottic cartilage is covered by a mucous membrane
arytenoid cartilage a pyramid shaped cartilage located on the superior margin of the cricoid lamina paired; each is connected to the epiglottis above via the aryepiglottic m. and to the thyroid cartilage anteriorly via the vocal ligament; paired arytenoid cartilages are pulled together (adducted) by the arytenoid m.
corniculate cartilage a small cartilage located on the apex of the arytenoid cartilage corniculate cartilage is found in the base of the aryepiglottic fold; it is yellow elastic cartilage
cricoid cartilage the inferior & posterior cartilage of the larynx; it forms a complete cartilaginous ring; its arch projects anteriorly and its lamina is broad and flat posteriorly connected: above to the thyroid cartilage via the inferior horn of the thyroid cartilage, to the conus elasticus, to the arytenoid cartilages which sit atop the lamina; connected below to the first tracheal ring via the cricotracheal ligament
cuneiform cartilage small cartilaginous nodule located in the aryepiglottic fold cuneiform cartilage is yellow elastic cartilage


Muscles of the Larynx

Muscle Origin Insertion Action Innervation Artery Notes
sternothyroid posterior surface of the manubrium below the origin of the sternohyoid m. oblique line of the thyroid cartilage depresses/stabilizes the hyoid bone ansa cervicalis superior thyroid a. sternothyroid lies deep to the sternohyoid m.
thyrohyoid oblique line of the thyroid cartilage lower border of the hyoid bone elevates the larynx; depresses/stabilizes the hyoid bone ansa cervicalis (via fibers running with the hypoglossal nerve that leave XII distal to the superior limb of ansa) superior thyroid a. thyrohyoid lies deep to the sternohyoid
stylopharyngeus medial side of the styloid process superior border of the thyroid cartilage and also into the pharyngeal wall elevates the larynx glossopharyngeal nerve (IX) ascending pharyngeal a. stylopharyngeus, the only muscle innervated by IX, is the only muscle of the pharyngeal wall NOT innervated by the vagus (X) nerve; it is a derivative of the third pharyngeal arch
palatopharyngeus posterior margin of the bony palate and the palatine aponeurosis posterior wall of the pharynx and the posterior margin of the thyroid cartilage elevates the larynx vagus nerve (X) via pharyngeal plexus ascending pharyngeal a. palatopharyngeus is part of the inner longitudinal muscle layer of the pharynx
posterior cricoarytenoid posterior surface of the lamina of the cricoid cartilage muscular process of the arytenoid cartilage draws the muscular process posteriorly, which pivots the arytenoid cartilage and abducts the vocal folds inferior laryngeal nerve, from the recurrent laryngeal nerve, a branch of the vagus nerve (X) superior laryngeal a., cricothyroid branch of the superior thyroid a. the posterior cricoarytenoid is the only ABductor of the vocal folds; the arteries that supply the larynx anastomose within the larynx to supply the mucous membranes and muscles
arytenoid, oblique muscular process of the arytenoid cartilage posterior surface of the contralateral arytenoid cartilage, near its apex draws arytenoid cartilages together, adducting the vocal folds inferior laryngeal nerve, from recurrent laryngeal nerve, a branch of the of vagus (X) laryngeal br. of the superior thyroid a. the oblique arytenoid m. lies posterior to the transverse arytenoid m.; the arytenoideus is often considered to be one muscle with oblique and transverse fibers
arytenoid, transverse posterior surface of the arytenoid cartilage posterior surface of the contralateral arytenoid cartilage draws arytenoid cartilages together, adducting the vocal folds inferior laryngeal nerve, from recurrent laryngeal nerve, a branch of the vagus nerve (X) laryngeal br. of the superior thyroid a. the transverse arytenoid m.lies anterior to the oblique arytenoid m.; the arytenoideus is often considered to be one muscle with oblique and transverse parts
aryepiglottic apex (superior part) of the arytenoid cartilage epiglottis draws the epiglottis posteriorly and downward during swallowing inferior laryngeal nerve, from recurrent laryngeal nerve, a branch of the of vagus (X) laryngeal br. of the superior thyroid a. the mucosa is raised by the underlying aryepiglottic m. to form the aryepiglottic fold
cricothyroid arch of the cricoid cartilage inferior border of the thyroid cartilage draws the thyroid cartilage forward, lengthening the vocal ligaments external branch of superior laryngeal nerve, a branch of the vagus nerve (X) cricothyroid branch of the superior thyroid a. this is the only intrinsic muscle of the larynx that is not supplied by the recurrent laryngeal n.; ALL other laryngeal muscles are innervated by recurrent laryngeal nerve, via its inferior laryngeal branch
lateral cricoarytenoid arch of the cricoid cartilage muscular process of the arytenoid cartilage draws the muscular process of the arytenoid cartilage anteriorly, which pivots the arytenoid cartilage and adducts the vocal folds inferior laryngeal nerve, from the recurrent laryngeal nerve, a branch of the vagus nerve (X) superior laryngeal a., cricothyroid branch of the superior thyroid a. an antagonist of the posterior cricoarytenoid m.; the arteries that supply the larynx anastomose within the larynx to supply the mucous membranes and muscles
thyroarytenoid inner surface of the thyroid cartilage anteriorly lateral border of the arytenoid cartilage draws the arytenoid cartilage forward, relaxing and adducting the vocal folds inferior laryngeal nerve, from recurrent laryngeal nerve, a branch of the vagus nerve (X) laryngeal branch of the superior thyroid a. its subsidiary parts are the thyroepiglottic m. and the vocalis m.; the medial most fibers of thyroarytenoid that insert along the vocal ligament are called the vocalis muscle
thyroepiglottic inner surface of the thyroid cartilage near the laryngeal prominence lateral surface of the epiglottic cartilage draws the epiglottic cartilage downward inferior laryngeal nerve, from recurrent laryngeal nerve, a branch of the vagus nerve (X) laryngeal branch of the superior thyroid a. represents the superior fibers of thyroarytenoid muscle which fan out to the quadrangular membrane and epiglottis
vocalis surface of the thyroid cartilage, vocal process of the arytenoid cartilage vocal ligament relaxes segments of the vocal ligament, thereby adjusting pitch inferior laryngeal nerve, from the recurrent laryngeal nerve, a branch of the vagus nerve (X) laryngeal br. of the superior thyroid a. represents the innermost fibers of the thyroarytenoid muscle; the cricothyroid m. grossly tenses the vocal ligaments, while the vocalis muscle provides the mechanism for fine tuning the vibrations of the vocal folds
constrictor, inferior pharyngeal oblique line of the thyroid cartilage, lateral surface of cricoid cartilage midline pharyngeal raphe constricts pharyngeal cavity vagus (X), via the pharyngeal plexus, with aid from the superior laryngeal and recurrent laryngeal nerves ascending pharyngeal a., superior thyroid a., inferior thyroid a. the most external of the three pharyngeal constructor mm.
cricopharyngeus lateral surface of the cricoid cartilage midline pharyngeal raphe constricts the pharyngeal cavity and the entrance to the esophagus recurrent laryngeal nerve, a branch of the vagus nerve (X) cricothyroid branch of the superior thyroid a., ascending pharyngeal a. cricopharyngeus represents the lowest fibers of the inferior pharyngeal constrictor; it is continuous with the esophagus below and marks the beginning of it


Nerves of the Larynx

Nerve Source Branches Motor Sensory Notes
laryngeal, inferior recurrent laryngeal br. of the vagus n. (X) no named branches all intrinsic muscles of the larynx except the cricothyroid; those muscles are: thyroarytenoid, oblique and transverse arytenoid, posterior and lateral cricoarytenoid, aryepiglottic, thyroepiglottic, vocalis; secretomotor to the mucous membrane of the larynx below the vocal fold mucous membrane of the larynx below the vocal fold inferior laryngeal n. is the continuation of the recurrent laryngeal n., the name change occurs at the cricothyroid articulation
superior laryngeal n. vagus n. (X) internal br., external br. cricothyroid m., inferior pharyngeal constrictor m.; secretomotor to mucosal glands of the larynx above the vocal folds mucous membrane of the larynx above the vocal folds external br. supplies the cricothyroid m.; all other intrinsic muscles of the larynx are supplied by the recurrent laryngeal n.
recurrent laryngeal n. vagus n. (X) esophageal brs., tracheal brs., cardiac brs., pharyngeal brs., inferior laryngeal n. upper esophagus, lower pharynx, laryngeal mm. (except cricopharyngeus); smooth muscle of the trachea; secretomotor to mucosal glands in the upper esophagus, lower pharynx, larynx below the vocal fold, trachea; cardiac muscle of the heart (slows heart rate, decreases force of contraction) upper esophagus, lower pharynx, larynx below the vocal folds, GVA from heart right recurrent laryngeal n. loops posteriorly around the right subclavian a.; left recurrent laryngeal n. loops posteriorly around the aortic arch and ligamentum arteriosum; the inferior laryngeal br. supplies all intrinsic muscles of the larynx EXCEPT the cricothyroid m.


Arteries of the Larynx

Artery Source Branches Supply to Notes
superior laryngeal superior thyroid a. no named branches internal aspect of the superior larynx superior laryngeal a. penetrates the thyrohyoid membrane in company with the internal br. of the superior laryngeal n.
inferior laryngeal inferior thyroid a. no named branches internal part of the inferior larynx inferior laryngeal a. accompanies the inferior laryngeal n.
cricothyroid superior thyroid a. no named branches cricothyroid m., inferior pharyngeal constrictor m. cricothyroid a. travels with the external br. of the superior laryngeal n.
thyroid, inferior thyrocervical trunk ascending cervical a., inferior laryngeal a., esophageal brs., tracheal brs., glandular brs. thyroid gland, lower larynx, upper trachea, upper esophagus, deep neck muscles inferior thyroid a. gives rise to the ascending cervical a. as it arches medially
caroticotympanic internal carotid a. no named branches tympanic cavity caroticotympanic a. courses through the petrous portion of the temporal bone


Viscera

Organ Location/Description Notes
vestibular fold fold of mucosa located between the laryngeal vestibule and the laryngeal ventricle also known as: false vocal fold
vocal folds fold of mucosa covering the vocal ligament and the thyroepiglottic muscle (vocalis part) located inferior to the laryngeal ventricle; also known as: true vocal fold
laryngeal ventricle lateral outpouching of the laryngeal mucosa located between the vestibular fold (false vocal fold) and the vocal fold (true vocal fold) laryngeal ventricle may have a small diverticulum called the saccule
laryngeal vestibule opening into the larynx; the part of the larynx located below the epiglottis, between the aryepiglottic folds and above the vestibular (false vocal) folds lateral wall of the laryngeal ventricle contains the quadrangular membrane (submucosa)
rima glottidis the opening between the vocal folds the glottis is the vocal fold plus the rima glottidis
glottis the vocal folds plus the rima glottidis rima glottidis is the opening between the vocal folds
infraglottic cavity the portion of the laryngeal cavity that lies inferior to the vocal folds bounded superiorly by the glottis and opens inferiorly into the trachea
aryepiglottic fold a fold of mucous membrane within the laryngopharynx that extends from the arytenoid cartilage to the epiglottis aryepiglottic fold covers the aryepiglottic muscle
conus elasticus elastic membrane attaching on the upper margin of the arch of the cricoid cart and ending in the vocal ligament thickened upper margin of the conus elasticus is the vocal ligament
vocal ligament an elastic band of connective tissue located in the vocal fold paired; each vocal ligament is connected to the inner surface of the thyroid cartilage anteriorly and to the vocal process of the arytenoid cartilage posteriorly; vocal ligament is the thickened superior margin of the conus elasticus; vibration creates sound; adducted by the actions of the arytenoid mm. and lateral cricoarytenoid m.; abducted by the action of the posterior cricoarytenoid m.
laryngopharynx the portion of the pharynx located posterior to the laryngeal inlet and the posterior wall of the larynx connects: superiorly with oropharynx at the superior border of epiglottis, anteriorly with the larynx through laryngeal inlet, inferiorly with the esophagus at the lower border of the cricoid cartilage; laryngopharynx contains the piriform recesses which are lateral to the aryepiglottic folds
larynx located anterior to the laryngopharynx at level of C4-6 vertebrae composed of: thyroid, cricoid, epiglottic, arytenoid, cuneiform & corniculate cartilages; contains the vocal ligaments; controls the airway
lateral glossoepiglottic fold fold of mucous membrane located between the base of the tongue and the epiglottis lateral glossoepiglottic fold is located lateral to the valleculae epiglottica
median glossoepiglottic fold fold of mucosa located between the base of the tongue and the epiglottis separates the paired valleculae epiglottica
piriform recess shallow depression located lateral to the aryepiglottic fold in the laryngopharynx the internal branch of the superior laryngeal n. is located immediately deep to the mucosa in this region; also known as: piriform fossa
trachea main airway that lies anterior to the esophagus trachea extends from vertebral level C6 to the level of the T4/5 intervertebral disc; superiorly it is connected to the cricoid cartilage via the cricotracheal ligament; it bifurcates into two primary bronchi
valleculae epiglottica fossa located between the base of the tongue and the epiglottis paired; each of the valleculae epiglottica is located between the median glossoepiglottic fold and the lateral glossoepiglottic fold



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Some of the material presented in these tables is contained in the book:
MedCharts Anatomy by Thomas R. Gest and Jaye Schlesinger
Published by ILOC, Inc., New York. Copyright 1995.

Content of these tables has been edited for use in this course by Patrick W. Tank, Ph.D.
Copyright 2007, Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences.

Unauthorized use is prohibited.