CAVITY OF THE LARYNX

ByJini Abraham

Laryngeal cavity is lined by the respiratory epithelium except the vocal cords and parts of epiglottis, which is lined by the stratified squamous epithelium.

The cavity starts at the laryngeal inlet where it communicates with the pharynx and ends at the lower border of the cricoid cartilage where it continues with the lumen of trachea.

The laryngeal inlet is bounded –Anteriorly – free margin of epiglottisLaterally – Aryepiglottic foldPosteriorly – Interarytenoid fold

Laryngeal interior is divided by two folds into three parts –

SupraglottisVestibuleVentricle

GlottisSubglottis

DIVISIONS

Folds dividing the cavity are – Vestibular folds –

False vocal cordsTwo in numberEach is fold of mucous membrane extending anteroposteriorly across laryngeal cavity

Contains vestibular ligament, few fibres of thyroarytenoideus muscle and mucous glands

Vocal folds – True vocal cordsTwo pearly-white shaped bands extending from the middle of thyroid angle to vocal processes of arytenoids

Each vocal cord consists of vocal ligament

Mainly constitutes –

EpiglottisAryepiglottic

foldsArytenoidsFalse cords

SUPRAGLOTTIS

Extends from laryngeal inlet to vestibular folds

Anterior wall formed by posterior surface of epiglottis

Sides by aryepiglottic foldsPosterior wall by mucous

membrane over anterior surface of arytenoids

VESTIBULE

Sinus of larynxDeep elliptical space between

vestibular and vocal folds

VENTRICLE

Diverticulum of mucous membrane which starts from the anterior part of ventricular cavity and extends upwards between vestibular folds and lamina of thyroid cartilage

Laryngocele – air containing sac present in the neck

Presence of mucous glands

SACCULE OF LARYNX

Rima glottidisElongated space between vocal cords

anteriorly and vocal processes and arytenoids posteriorly

24mm in men and 16mm in womenNarrowest part of laryngeal cavityAnterior two-thirds formed by

membranous cords and posterior one-third by vocal processes of arytenoids

GLOTTIS

Size and shape of glottis varies with movements of vocal cords

Infraglottic larynxExtends from vocal cords to lower

border of cricoid cartilage

SUBGLOTTIS

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