ANATOMY OF LARYNXDR VIJAY NAGDEVFCPS-II TRAINEEANAESTHESIOLOGYCIVIL HOSPITAL,DUHS KARACHI
LARYNX It is the musculocartilaginous structure, linedwith mucous membrane, connected to the superior part of the trachea andto the pharynx. the essential sphincter guarding the entrance intothe trachea. functioning secondarily as the organ of voice. It is formed by nine cartilages connected `byligaments and eight muscles. begins at the level of vertebra C4or C5and endsat the level of vertebra C7
The Anatomy of the LarynxFigure 23.4pgmedicalworld.com
CARTILAGES There are 9 cartilages of larynx 3 are paired and 3 are unpairedUNPAIRED• Thyroid cartilage• Cricoid cartilage• EpiglottisPAIRED• Arytenoid• Corniculate• Cuneiform
THYROID CARTILAGE The largest laryngeal cartilage (“shield-shaped”) It forms most of the anterior and lateral wallsof the larynx . The thyroid cartilage, when viewed insagittal section, is incomplete posteriorly. The anterior surface of this cartilage bears athick ridge, the laryngeal prominence. This ridge is easily seen and felt, and thethyroid cartilage is commonly called theAdam’s apple.
CARTILAGESA. THYROID CARTILAGE – Shield shaped- has Sup. & Inf. Horns from upper & lower edgesLaryngealProminenceSup.HornsInf.Horns- Inf. horns make synovial hinges joint with Cricoid Cartilage;- Laryngeal Prominence = Adam’s Apple, more prominent inmales pgmedicalworld.com
CRICOID CARTILAGE “ringshaped” cartilage. It is a complete ring whose posteriorportion is greatly expanded, providingsupport in the absence of the thyroidcartilage. Forms most of the posterior wall of larynx The cricoid and thyroid cartilages protectthe glottis and the entrance to the trachea
EPIGLOTIS• Thin, leaf-like, elastic fibrocartilage• Projects upward behind tongue & hyoid• During swallowing, the larynx is elevated,and the epiglottis folds back over theglottis, preventing the entry of liquids orsolid food into the respiratorypassageways.• Neonates & infants – omega shaped, long,floppy
LARYNX: CARTILAGESF. EPIGLOTTIS- leaf shapedcartilageposterior to rootof tongue- connected tobody of hyoidand post side ofthyroid cartilagePOST. VIEWpgmedicalworld.com
EXTRINSIC LIGAMENTS OFLARYNX1. Thyrohyoid ligamentlinks larynx to hyoid;2. Cricothyroid ligamentlinks thyroid to cricoid;3. Cricotracheal ligamentlinks Cricoid to firsttracheal cartilageMedianThyrohyoidLigamentMedianCricothyroidLigamentpgmedicalworld.comConects cartilages to hyoid and trachea
INTRINSIC LIGAMENTSEpiglottis1. QuadrangularMembrane linksArytenoidTo epiglottisForms the vestibular ligamentArytenoidpgmedicalworld.com2.CONUSELASTICUS:forms vocalligament ,framework ofvocal fold / truecordConnects cartilages to each other andforms the internal framework
CAVITY OF LARYNX Cavity of larynx contains the vestibularfolds,vocal folds,glottis These vestibular folds and vocal foldsdivide cavity of larynx into 3compartmentso Superior vestibuleo Ventricle / sinus of the larynxo Subglottic space
Glottis It is the vocal apparaus of larynx Makes up the vocal folds and processestogether with rima glottidis
Vocal folds (true vocal cords)• These are the sharp edged folds of mucusmembrane• source of sound from larynx• They produce audible vibrations• Act as sphincter when tightly adducted
Vestibular folds(false vocalcords) They are protective in function No function in voice production They become swollen during anaphylacticshock causing suffocation
INTRINSIC MUSCLES All the Intrinsic muscles of the larynx are pairedexcept tranverse inter arytenoid muscle. These are: 1)abductors of vocal cords=posterior crico-arytenoid. 2)adductors of vocal cords=lateral crico-arytenoid,interarytenoid,thyroarytenoid,cricothyroid. 3)tensors & adductors of vocalcords=cricothyroid,vocalis & thyro-arytenoid. 4)openers of the laryngeal inlet=thyroepiglottic 5)closers of the laryngeal inlet=interarytenoid &aryepiglottic.
EXTRINSIC MUSCLES These are divided into two groups: 1)cervical muscles: A)suprahyoid muscles,which act aselevators of the larynx B)infrahyoid muscles(strapmuscles),which acts as depressors of thelarynx. 2)pharyngeal muscles including theinferior constrictor muscle.
MUSCLES OF LARYNX1)THYROARYTENOIDMUSCLE -RelaxesVocal LigamentsDecreases pitchNOSEpgmedicalworld.com
MUSCLES OF LARYNX2) ARYTENOID(Transverse andoblique arytenoid) -Adduct vocal folds3) LATERAL CRICO-ARYTENOID- Adductvocal folds4) POSTERIORCRICOARYTENOID– Abductsvocal foldAdduct closes rima glottidisAbduct opens rima glottidisArytenoidsCan rotate/slide pgmedicalworld.com
NERVES OF LARYNX –Branches of VagusA. Superior Laryngeal N.divides to -1. Internal Laryngeal N.GVA Sensory to LarynxAbove True Vocal Folds2. External Laryngeal N.SVE Motor to CricothyroidB. Recurrent Laryngeal N.- GVA Sensory to LarynxBelow True Vocal Folds- SVE motor to all otherMuscles of LarynxGVA=GENERAL VISCERALAFFERENTSVE=SPECIAL VISCERAL EFFERENTSUP. LARYNG. NInt. Laryng. N.Ext. Laryng. N.RECURRENTLARYNG. N.pgmedicalworld.com