LARYNX Introduction Skeletal framework consists of 3 unpaired and 3 paired cartilages connected to each other by ligaments , membrane.

Location:- In adult male lie opposite to 3rd to 6th cervical vertebrae Male Female

Length 44mm 36mm

Transverse 43mm 41mm Diameter Cartilages of Unpaired cartilages:- • Thyroid • Cricoid • Paired cartilages • Arytenoid • Corniculate • Cuneiform Cartilages of Larynx Larynx Thyroid cartilage • Consists of two quadrilateral laminae which meet in the midline called thyroid angle • Which is acute in male and obtuse in female • The angle measures 90 degrees in male and 120 degrees in female Thyroid cartilage Thyroid cartilage Posterior border of each lamina is free and prolonged upwards and downwards as superior and inferior horns /cornu provides attachment to 3 muscles 1. Salpingopharyngeus 2. Palatopharyngeus 3. Stylopharyngeus Thyroid cartilage-showing horns Thyroid cartilage • Posterior surface provides attachment to 1.Thyroepiglottic ligament 2.A pair of vestibular ligament 3.A pair of vocal ligament Thyroid cartilage The outer surface of each lamina there is oblique line ,it provides attachment to three muscles 1.Thyrohyoid 2.Sternothyroid 3.Inferior contrictor (Thyropharyngeus part) Cricoid cartilage • It is signet-ring shaped cartilage • Situated at the level of C6 vertebra , • It completely encircles the lumen of larynx Cricoid cartilage Epiglottis • Leaf like extends behind the hyoid bone and base of • Its broad upper end is free and forms upper boundary for laryngeal inlet • Lower end is pointed and connected to posterior surface of angle of thyroid cartilage by thyroepiglottic ligament Epiglottis Epiglottis • The anterior surface is connected with the base of tongue by median and lateral glossoepiglottic folds. • Vallecula:- depression on each side of median fold • Posterior surface has a tubercle Median and lateral glossoepiglottic folds Arytenoid cartilage • Articulate with the upper border of cricoid cartilage • Each arytenoid cartilage is pyramidal and presents apex, base, Surfaces:-Posterior,anterolateral,medial Has two processes 1.Muscular process 2. Vocal process Arytenoid cartilage Corniculate cartilage • Conical nodules which articulate with the apices of the arytenoid cartilages Cuneiform cartilage • Tiny rod-shaped cartilages lying in the posterior parts of the aryepiglottic folds

Inlet of larynx • Bounded anteriorly by EPIGLOTTIS • Each side ARYEPIGLOTTIC FOLD of • Inferiorly by INTERARYTENOID FOLD of mucous membrane Inlet of larynx Muscles of Larynx Extrinsic muscles • Palatopharyngeus • Salpingopharyngeus • Stylopharyngeus • Thyrohyoid • Sternothyroid Intrinsic muscles of Larynx • Oblique arytenoids • Aryepiglottis • Thyroepiglotticus • Posterior cricoarytenoids • Lateral cricoarytenoids • Transverse arytenoids • Cricothyroid • Vocalis • Thyroarytenoids Action of muscles of Larynx

Muscles that open or close the laryngeal inlet 1.Oblique arytenoids-close inlet of larynx 2.Aryepiglotticus-close inlet of larynx 3.Thyroepiglotticus-Opens the inlet of larynx Muscles that abduct or adduct the vocal cords 1.Posterior cricoarytenoids-abduct the vocal cords 2.Lateral cricoarytenoids-adduct the vocal cords 3.Transverse arytenoids – adduct the vocal cords Muscles that increase or decrease the tension of vocal cords • Cricothyroids – tenses the vocal cords • Vocalis- Tenses the vocal cords • Thyroarytenoids- relaxes the vocal cords Cricothyroid muscle

• Origin- Anterolateral aspect of the cricoid cartilage • Insertion- inferior cornu and adjacent lower border of lamina of thyroid cartilage Cricothyroid muscle Nerve supply to cricothyroid muscle Posterior cricoarytenoid

• Origin- Posterior surface of cricoid lamina • Insertion- muscular process of arytenoid Posterior cricoarytenoid Cavities of larynx Nerve supply

Motor nerve supply All intrinsic muscles of larynx are supplied by RECURRENT LARYNGEAL NERVE except cricothyroid which Is supplied by EXTERNAL LARYNGEAL NERVE Recurrent laryngeal nerve Sensory nerve supply • The mucous membrane of larynx above the vocal folds supplied by INTERNAL LARYNGEAL NERVE while the vocal folds below is by RECURRENT LARYNGEAL NERVE Blood supply • Above the vocal fold- superior laryngeal vessels • Below the vocal fold-inferior laryngeal vessels Rima glottidis • It is the narrowest anteroposterior cleft of the laryngeal cavity • The anteroposterior diameter of glottis is 24mm in adult male and 16mm in adult females

Rima glottidis Subdivision of Rima glottidis • Intermembranous part:- anterior 3/5th between vocal cords • Intercartilaginous part- posterior 1/5th between the vocal process of the arytenoid cartilage Cricothyroid membrane- emergency tracheotomy Procedure for emergency tracheostomy