40 Laryngeal Anatomy and Physiology
40.1 Anatomy
40.1.1 Cartilages
• Thyroid
Two laminae fused in midline anterior
Superior cornu articulates with greater horn of hyoid
Inferior cornu forms synovial joint with cricoid
An oblique line along lateral surface of lamina allows for attachment of sternothyroid and thyrohyoid muscles
Inferior pharyngeal constrictor attaches to posterior border of lamina
• Cricoid
Complete solid ring cartilage
Superior articulation with the inferior cornu of thyroid cartilage
Inferior a membrane attaches to first tracheal ring
Anterior the ring is narrow compared with posterior
The cricothyroid membrane is formed between these aspects of the ring
• Arytenoid
Two pyramid-shaped cartilages
They articulate with posterior part of cricoid (cricoarytenoid joint).
Muscular process is lateral where the intrinsic laryngeal muscles attach
Vocal process medial where the vocal ligament attaches
• Accessory: Cuneiform and corniculate cartilages
Both intimately related to arytenoids providing support to aryepiglottic folds
• Epiglottis
Superior is free edge
Inferiorly it attaches to the inner surface of the thyroid cartilage superior to anterior commissure
40.1.2 Muscles
• Extrinsic
Infrahyoid and suprahyoid muscles
• Intrinsic
Adductors
– Lateral cricoarytenoid*
– Thyroarytenoid*
– Interarytenoid
Unpaired with bilateral nerve innervation, hence unilateral RLN palsy can still result in some adduction
• Abductor
Posterior cricoarytenoid
* Control vocal length, tension and frequency
40.1.3 Joints
• Cricothyroid
Synovial joint
2 actions: antero-posterior sliding and rotation inferior cornu on cricoid
Contraction pulls thyroid ala anterior resulting in lengthening and tension of vocal cords (VCs)
• Cricoarytenoid
Each joint is placed 45° to the horizontal on the cricoid
Allows for arytenoid rocking, sliding which alters the vocal process position which affects the VCs
40.1.4 Fibroelastic Tissue
• Quadrangular membrane
Accessory elastic support

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