H 4. Anatomy of Phonation
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Title
Chapter 4 Anatomy of Phonation
Authors
Anatomy & Physiology of Speech Anatomy & Physiology for Speech, Language, and Hearing, Sixth Edition by J. Anthony Seikel, David G. Drumright, Daniel J. Hudock.
Credits
Copyright © 2021 by Plural Publishing
Institution
DeSales University Communication Sciences and Disorders
Instructor
Mahdi Tahamtan, Ph.D. CSD 225 Anatomy & Physiology of Speech
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Structure of the Larynx
Musculo-cartilaginous structure at the superior end of the trachea
Composed of:
3 unpaired cartilages: cricoid, thyroid, epiglottis
3 paired cartilages: arytenoid, corniculate, cuneiform
Bounded by ligaments and lined with mucous membranes
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Location of the Larynx
The larynx sits atop the last tracheal ring
Adjacent to cervical vertebrae C4-C6 in adults
Average length:
Adult males: 44 mm
Adult females: 36 mm
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Laryngeal Cartilages
Epiglottis: Leaf-like structure
Lateral thyrohyoid ligament
Cuneiform cartilage: Small cartilages embedded in membranes
Thyroid notch: V-shaped depression while Laryngeal prominence (Adam's apple) is more pronounced in men
Anterior and posterior views of the larynx show its structural complexity
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Detailed Anatomy of Larynx
Structures like thyrohyoid ligament, thyroid lamina, arytenoid cartilages are visible
The lateral view highlights the cricothyroid ligament and the muscular and vocal processes of the arytenoids
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Thyroid Cartilage
Largest cartilage of larynx
Prominent anterior surface created by thyroid laminae
Thyroid notch: Depression at the angle of the thyroid
Laryngeal prominence: Notable feature for identification
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Features of Thyroid Cartilage
Posterior aspect with two sets of horns:
Superior horn: articulates with hyoid bone
Inferior horn: articulates with cricoid cartilage
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Cricoid Cartilage
Complete ring resting atop trachea
Largest in circumference compared to trachea, higher at the back than front
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Joints in Cricoid Cartilage
Superior facets: Articulate with arytenoid cartilages
Cricoarytenoid joints: Allow rotation of arytenoid on cricoid
Cricothyroid joints: Facilitate movement of thyroid cartilage
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Functionality of Cricoid Cartilage
Contains facets for arytenoid and thyroid
Engages in pivotal movements crucial for sound production
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Cricoid Cartilage and Related Structures
Median cricothyroid ligament: Connects cricoid and thyroid
Conus Elasticus: Forms vocal ligament
Vocal folds are foundational for phonation
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Structure of the Epiglottis
The unpaired epiglottis is leaf-like; connected to thyroid cartilage via thyroepiglottic ligament
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Relation of Epiglottis and Larynx
Sides joined with arytenoid cartilages via aryepiglottic folds
significant for swallowing and airway protection
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Function of the Epiglottis
During swallowing, food passes over, diverting to pyriform sinuses
Pyriform sinuses are important for food passage and airway safety
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Arytenoid Cartilages
Pyramid-shaped, located on cricoid cartilage
Corniculate cartilages sit atop the apex of arytenoids
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Vocal Processes of Arytenoid Cartilages
Project anteriorly toward thyroid notch
Important for attachment of vocal folds
Muscular process: key for adducting and abducting vocal folds
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Cuneiform Cartilages
Embedded in aryepiglottic folds
Produce small bulges under illumination
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Hyoid Bone Overview
Unpaired bone, not attached to others
Supports the structure of the larynx and the tongue
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Elements of Hyoid Bone
Corpus
Greater cornu
Lesser cornu
Nine muscles attach, facilitating movement
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Muscular Attachments to Hyoid Bone
Anterior Belly of Digastric
Geniohyoid
Stylohyoid
Posterior Belly of Digastric
Hyoglossus
Mylohyoid
Sternohyoid
Omohyoid
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Hyoid Bone Resources
Reference links provided for further anatomical understanding
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Movement of Cartilages - Cricothyroid Joint
Allows rocking and sliding motions of thyroid cartilage, crucial for pitch changes
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Movement of Cartilages - Cricoarytenoid Joint
Enables various movements: rocking, gliding, minimal rotation
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Detailed Cartilage Movements
Rocking Motion
Closes vocal folds by bringing vocal processes together
Gliding Motion
Facilitates length changes in vocal folds
Rotation
Limited to extreme abduction
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Summary of Movements
Rocking Motion: Critical for closing VFs
Gliding Motion: Aids in adjusting VF length
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Palpation of the Larynx
Method for identifying laryngeal structures: thyroid notch, margin palpation guides