Laryngeal Anatomy and Physiology

40 Laryngeal Anatomy and Physiology


40.1 Anatomy


40.1.1 Cartilages


• Thyroid


figure Two laminae fused in midline anterior


figure Superior cornu articulates with greater horn of hyoid


figure Inferior cornu forms synovial joint with cricoid


figure An oblique line along lateral surface of lamina allows for attachment of sternothyroid and thyrohyoid muscles


figure Inferior pharyngeal constrictor attaches to posterior border of lamina


• Cricoid


figure Complete solid ring cartilage


figure Superior articulation with the inferior cornu of thyroid cartilage


figure Inferior a membrane attaches to first tracheal ring


figure Anterior the ring is narrow compared with posterior


figure The cricothyroid membrane is formed between these aspects of the ring


• Arytenoid


figure Two pyramid-shaped cartilages


figure They articulate with posterior part of cricoid (cricoarytenoid joint).


figure Muscular process is lateral where the intrinsic laryngeal muscles attach


figure Vocal process medial where the vocal ligament attaches


• Accessory: Cuneiform and corniculate cartilages


figure Both intimately related to arytenoids providing support to aryepiglottic folds


• Epiglottis


figure Superior is free edge


figure Inferiorly it attaches to the inner surface of the thyroid cartilage superior to anterior commissure


40.1.2 Muscles


• Extrinsic


figure Infrahyoid and suprahyoid muscles


• Intrinsic


figure Adductors


– Cricothryoid*


– Lateral cricoarytenoid*


– Thyroarytenoid*


– Interarytenoid


figure Unpaired with bilateral nerve innervation, hence unilateral RLN palsy can still result in some adduction


• Abductor


figure Posterior cricoarytenoid


* Control vocal length, tension and frequency


40.1.3 Joints


• Cricothyroid


figure Synovial joint


figure 2 actions: antero-posterior sliding and rotation inferior cornu on cricoid


figure Contraction pulls thyroid ala anterior resulting in lengthening and tension of vocal cords (VCs)


• Cricoarytenoid


figure Each joint is placed 45° to the horizontal on the cricoid


figure Allows for arytenoid rocking, sliding which alters the vocal process position which affects the VCs


40.1.4 Fibroelastic Tissue


• Quadrangular membrane


figure Accessory elastic support

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Jul 4, 2016 | Posted by in OTOLARYNGOLOGY | Comments Off on Laryngeal Anatomy and Physiology

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