LARYNX C3-C6

Connects oropharyngeal isthmus to trachea.

Cartilages, muscles, ligaments and mucous membrane

Quadrangular membrane forms the superior and conus elasticus forms the inferior membranes of larynx.

Functions

1) guard air passages while swallowing2) phonation / voice production

cartilages

1) tyroid cartilage – SINGLE - LARGEST

C3- At the anterior regions, 2 laminae of it fuse to form LARYNGEAL PROMINENCE – adam’s apple

Superior to this prominence is V shaped superior tyroid notch.

Between inferior and superior tyroid TUBERCLES -> oblique line

At posterior side, laminae project as superior and inferior horns.

Superior borders and horns are attached to HYOID bone by tyrohyoid membrane.

2) Inferior horns articulate with CRICOID CARTILAGE by cricotyroid joints (pivot) and ligements. SINGLE-

Rotation of cricotyroid joints causes changes in the length of vocal folds.

Anterior side is ARCH,

posterior is LAMINA.

Thicker and stronger – only complete ring that encircles the airway.

Attached to inferior margin of tyroid cartilage by MEDIAN CRICOTYROID LIGAMENT

To tracheal ring by CRICOTRACHEAL LIGAMENT

3) Arytenoid cartilages – PAIRED –

Pyramidal – artculation with lamina of cricoid cartilages.

Superior : apex – corniculate cartilage

Anterior : vocal process – posterior of vocal ligaments

Base: muscular process – posterior and lateral cricoarytenoid muscles are attached.

Arcuate crest on anterolateral surface– divides 2 depressions (foveae) into triangular and oblong. Triangular fovea attaches to vestibular ligament. To oblong depression: vocalis.

Function: movement alters tension on vocal cords

4) Corniculate cartilage - PAIRED– on the apex of arytenoid cartilage.

5) Eppiglottis – SINGLE - Elastic cartilage.

Posterior to root of tongue and hyoid bone, anteriorly to laryngeal inlet.

Superior end is free but its tapered inferior end (stalk of eppiglottis) is attached to angle formed by tyroid laminae via tyro-eppiglotic ligament. Anterior border is attached to hyoid bone by hyo-eppiglotic ligament. On the posterior surface : eppiglotic tuberle.

Anterior surface – lateral and median glossoeppiglotic folds. Between these folds is VALLECULA.

Thin submucosal sheet of connective tissue called QUADRANGULAR MEMBRANE between arytenoid and eppiglotis – VESTIBULE – inferior margins contain vesitbular ligament covered by mucosa to form vestibular fold. Superior of vocal folds.

Superior margins of quadrangular membrane forms ary-eppiglotic ligaments which are covered by mucosa to form ARY-EPPIGLOTIC FOLD.

6) Cuneiform cartilage – PAIRED – are not attached directly to any cartilage. Found within aryeppiglotic fold. Together with corniculate cartilage form corniculate and cuneiform tuberles on the ary-eppiglotic fold.

VOCAL FOLDS

Glottis: vocal apparatus of larynx – made up of vocal folds and processes

Function: sound production

vocal folds– superior border of conus elasticus membrane - extend from junction of laminae of tyroid cartilage anteriorly to vocal process of arytenoid posteriorly.

Each vocal fold consists of a vocal ligament and a vocal muscle.

Conus elasticus closes the tracheal inlet except rima glottidis – opening of vocal cords

During breathing; narrow. Forced respiration: wide

INTERIOR

Larynx superiorly opens to laryngopharynx via laryngeal inlet and inferiorly is limited at cricoid cartilage which connects laryngeal cavity to tracheal cavity.

Eppiglotis

Hyoid bone

Vestibule / quadrangular membrane

Vestibular fold

Laryngeal ventricle + saccule (glands)

Vocal foldInfraglottic cavity – bw vocal folds and cricoid cartilage inf border

Conus elasticus

Extrinsic Ligaments Intrinsic ligamentsTyrohyoid membrane 2 partsMedian and LateralPierce on lateral part for the passage of internal branch of superior laryngeal nerve, superior laryngeal artery and vein

Fibroelastic membranes are 2Conus elasticus (cricoid, tyroid angle, vocal process)and Quadrangular membrane (eppiglotis, arytenoid, corniculate)

Hypoeppiglotic ligament Thyroeppiglotic Ligament

Cricotracheal Ligament Posterior Cricoarytenoid ligament

Rima vestibuli: opening between 2 adjacent vestibular folds at the entrance of laryngeal cavity. Priform recess – for liquid

Intrinsic

Cricotyroid Oblique Straight External branch of laryngeal nerve

Tenses vocal ligaments

Posterior Cricoarytenoid

Recurrent larngeal nerve

Externally rotates arytenoid and ABDUCS VOCAL FOLDS

ONLY ABDUCTOR OF VOCAL CORDS

Lateral Cricoarytenoid

Reccurrent laryngeal nerve

Rotates arytenoid internally and 1)ADDUCTS VOCAL FOLDS

Arytenoid (intercartilageous part)

Transverse 1 Oblique 2 – continues to form aryeppiglotic muscle.

Reccurent laryngeal nerve

2) ADDUCTS VOCAL FOLDS

Thyroarytenoid Reccurent laryngeal nerve

Covers conus elasticus externally and reduces tension on vocal cords. 3)ADDUCTS VOCAL FOLDS

Thyroeppiglotic Reccurent laryngeal nerve

Closes aperture of eppiglotis and forms spinchter of larynx

Vocalis (thyroid and cricoid cartilages to arytenoid crtilages)

Reccurent laryngeal nerve

Sorrounds vocal folds and adjusts tension on cords.

NERVES

Vagus branches

1) Superior laryngeal nerve –> 2 branches. External and Internal.

External : cricotyroid muscle (motor)

Internal : general sensory and parasympathetic fibers

2) Inferior (recurrent) laryngeal nerve.

Motor innvervations of all layrngeal muscles except cricotyroid.

General sensory

Parasympathetic fibers

ARTERIES

Runs with superior laryngeal nerve

Runs with inferior laryngeal nerve

VEINS

Lymph nodes: upper and lower deep cervical lymph nodes around venous angle and aortic arch

Quiet resp: the laryngeal inlet, vestibule, rima

vestibuli and rima glottidis are open. Arytenoid cartilages are abducted.

Forced respi: vocal folds are abducted and rima glottidis is open. Vastibule is open.

Phonation: Vocal folds and arytenoid cartilages are ADDUCTED. Air is forced through closed rima glottidis.

Effort closure: rima glottidis is completely closed so rima vestibuli and vestibule are closed.

Swallowing: rima glottidis, the rima vestibuli, and vestibule are closed and the laryngeal inlet is narrowed. Larynx moves up and forward, pushing eppiglotis downward and toward arytenoid cartilages to close laryngeal inlet. This movement opens eosephaus as well.

RELATIONS

ANTERIOR Anterolateral Lateral Superior PosteriorSkin Sternocleidomastoid Tyroid gland Hyoid bone LaryngopharynxSuperficial cervical fascia

Sternohyoid Carotid sheat (common carotid artery, internal

jugular vein, vagus nerve)

Platystma SternotyroidPretrecheal fascia

Thyrohyoid

omohyoid