Voiceproblem.org: Anatomy and Physiology of Voice Production: How Breakdowns Result in Voice Disorders

How Breakdowns Result in Voice Disorders

Key Glossary Terms

Larynx
Highly specialized structure atop the windpipe responsible for sound production, air passage during breathing and protecting the airway during swallowing

Vocal Folds (also called Vocal Cords)
"Fold-like" soft tissue that is the main vibratory component of the voice box; comprised of a cover (epithelium and superficial lamina propria), vocal ligament (intermediate and deep laminae propria), and body (thyroarytenoid muscle)

Glottis (also called Rima Glottides)
Opening between the two vocal folds; the glottis opens during breathing and closes during swallowing and sound production

Glossary

In Brief

Voice disorders refer to breakdowns in the vibratory system. Breakdowns can affect any one or all of the three subsystems of voice production.

Air Pressure System

If the airflow source is weak or inefficient (making it difficult to push enough air out of lungs), the voice will be weak and hampered by shortness of breath.

For example: Patients with asthma, lung cancer, emphysema and other lung conditions often find it difficult to speak loud or for long periods of time.

Vibratory System

Any compromise or change to vocal fold vibration causes hoarseness and other voice symptoms.

For example: Patients with stiffness in the vocal folds from swelling from a common cold develop hoarseness.
For example: When focal folds cannot come perfectly together from partial nerve input loss, air leak occurs and the voice is "breathy."

Resonating System or Vocal Tract

A breakdown of the vocal tract can affect voice quality.

For example: When nasal passageways are swollen and inflamed during the "common cold," the voice takes on a nasal quality.

Making Sense of It All

The following are a few examples depicting how breakdowns result in voice disorders and a few of the many possible voice symptoms.

Correlating Anatomy, Voice Function, Abnormalities, and Possible Voice Disorder Symptoms

Sound Process	Brief Description	A Glimpse – "who does what" in Sound Production	Examples of "Breakdowns" that Affect Sound Process	Possible Symptoms
Generating Air Pressure	"Breath Support" Coordinated functions of diaphragm, abdominal and chest muscles, lungs and chest cavity move air column upwards through vocal folds	Diaphragm, abdominal and chest muscles move air into and out of lungs Lungs are the organs for air Bronchi and trachea are the passageway for air from lungs	Lung disease Airway obstruction: asthma, subglottic stenosis Paresis/paralysis of muscles	Shortness of breath Weak voice
Glottic Closure Position of vocal folds	Vocal Fold Position Critical Vocal folds are in closed position for speech or singing [Note: Vocal folds are open for breathing]	Laryngeal muscles contract to close vocal folds Arytenoid cartilages pivot to move vocal folds towards midline ["closed"] RLN and SLN bring nerve inputs to muscles Vocal fold mass and edge contribute to glottic closure	Paresis/paralysis–RLN/SLN Muscle weakness Neurological diseases; muscular disorders Arytenoid arthritis Vocal fold granuloma Vocal fold nodules, polyps, cysts Vocal fold atrophy Vocal fold scarring	Hoarseness Breathiness Effortful phonation Vocal fatigue Diplophonia
Vocal Fold Vibration Produces Voiced Sound	Wavelike Vibration from Bottom to Top–repeat vibratory cycles With each vocal fold vibratory cycle, a puff of air escapes, producing voice sound ("buzzy sound") Singing voice produces unique sound spectra (singing formants) that are distinct from spoken voice	Superficial lamina propria is the main vibrating layer in vocal fold mucosa Vocal fold pliability is critical for vibration Vocal fold surface integrity allows mucosal wave propagation Vocal fold mass and edge contribute to glottic closure	Vocal fold scar Vocal fold lesions: cysts, nodules, polyps, papilloma Vocal fold granuloma Swelling and inflammation (reflux laryngitis, viral laryngitis) Reinke's edema Paresis/paralysis Hemorrhage, vascular ectasias	Hoarseness Effortful phonation Weak voice Speaking voice lower than usual "Vocal fry" Voice fatigue
Voice Volume or Loudness	Amplitude of Sound Waves Loudness is achieved by: Increasing air pressure/flow Increasing vocal fold resistance	Breath support Laryngeal muscles contract to adjust tension of vocal folds Vocal fold elasticity allows folds to "open wider" and "stay apart" longer	Vocal fold scar Paresis/paralysis Vocal fold lesions: cysts, nodules, polyps, papilloma Vocal fold granuloma Swelling and inflammation (reflux laryngitis, viral laryngitis)	Unable to project voice Weak voice Voice breaks
Voice Pitch or Highness / Lowness	Frequency of Sound Waves Increased tension for high notes (high frequency) Decreased tension for low notes (low frequency) Greater air pressure and increased tension for high notes	Laryngeal muscles contract to adjust tension of vocal folds–especially for high notes Vocal fold elasticity/pliability Vocal fold edge integrity	SLN paresis/paralysis Vocal fold scar Reinke's edema Vocal fold lesions	Unable to hit high notes Loss of glissando Voice breaks
Voice Quality or Timbre	Person's "Own" Voice Vocal tract resonators amplify and modify voiced sound, giving personal quality to a person's voice e.g., John's voice not equal to Jim's voice	Vocal fold elasticity/pliability Vocal fold resistance Vocal fold mass Person's vocal fold features: e.g., stiffness, bulk, size Vocal tract resonators (throat, oral cavity, nasal cavities)	Vocal fold scar Vocal fold inflammation Reinke's Edema Common cold	Hoarseness, etc. Off expected pitch Nasal quality to voice

Learning About the Voice Mechanism

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