Larynx PDF

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Summary

Respiratory anatomy - overview of structure of the larynx....

Description

Larynx

3 compartments: Supraglottic (vestibule) - opening to vestibular fold. Ventricle - between vestibular and vocal folds. Infraglottic - vocal fold to inferior cricoid cartilage. The thyroid, cricoid and arytenoid cartilage are composed of hyaline cartilage. Epiglottic, corniculate and cuneiform cartilages are composed of elastic fibrocartilage.

Cricothyroid ligament/membrane: .

Vocal ligaments at free borders of each conus elasticus. They extend from the vocal processes of the arytenoid cartilages

Cricothyroid: ● 2 parts - straight and oblique. ● Act to pull thyroid cartilage anteriorly and inferiorly - effect is to lengthen vocal cords. ● Only intrinsic muscles to be innervated by the extrinsic laryngeal branch of the vagus nerve. Posterior cricoarytenoid: ● Abduct and externally rotate the arytenoids - open rima glottidis. ● Recurrent laryngeal nerve. Lateral cricoarytenoid: ● Adduct and internally rotate arytenoids - close rima glottidis. ● Recurrent laryngeal nerve. Interarytenoids (oblique and transverse): ● Adduct arytenoids - narrow rima glottidis. ● Recurrent laryngeal nerve. Vocalis: ● Run parallel to each vocal ligament. ● Adjust tension of vocal cords. Thyroarytenoid: ● Sphincter of the laryngeal vestibule. ● Function to narrow laryngeal inlet. Both - recurrent laryngeal nerve.

Laryngeal Blood Supply:

Superior (from external carotid) and inferior (from thyrocervical trunk) laryngeal arteries. Venous drainage via superior (to internal jugular) and inferior (to left brachiocephalic) laryngeal veins. Lymphatic Drainage: Above vocal folds: Deep cervical nodes associated with bifurcation of carotid. Below vocal folds: Deep nodes associated with upper trachea. Innervation: Mucous membrane of supraglottic compartment is innervated by the internal laryngeal nerve. Remaining mucous membrane in larynx is innervated by recurrent laryngeal nerve. Therefore: ● External - innervates the only muscle on the outside of the larynx - cricothyroid. ● Recurrent - supplies the remaining intrinsic muscles and mucous membrane of infraglottic compartment. ● Internal - supplies mucous membrane of ventricle and supraglottic compartments. All from CN X - vagus nerve. Motor - from external and recurrent laryngeal nerves. Sensory - from internal (above false vocal cords) and recurrent (below false vocal cords). False vocal cords (vestibular ligament) - superior to true (vocal ligament) - fold of tissue separating vestibule from ventricle. Recurrent laryngeal nerves: ● Branches of vagus (CN X). ● Left hooks around arch of aorta. ● Right hooks around subclavian. ● Ascend in neck in groove between oesophagus and trachea. ● Enter larynx posterior to cricothyroid joint. ● Motor to all intrinsic muscles of larynx except cricothyroid. ● Sensory to subglottic larynx and trachea....