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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