05 - Phonation I Flashcards
Phonatory/Laryngeal System
Which is the correct term: vocal folds or vocal cords?
Vocal folds, although they may also be called “true vocal folds” or “vocal cords”
What are the vocal folds?
A valve in the airway at the level of the larynx
What are the vocal folds composed of (3)?
Epithelial tissue, mucus membrane, and muscle tissue
What is the primary role of the vocal folds in speech?
To vibrate and thus generate the voice signal
Name 2 non-speech functions of the vocal folds
Protecting the airway (closing during swallowing, coughing)
Assisting in strenuous lifting or pushing
What other 2 structures, beside the vocal folds, play a role in protecting the airway during swallowing?
False vocal folds
Epiglottis
True or False: when the muscles of the larynx bring the vocal folds very close together and air from the trachea/lungs is pushed through, the vocal folds will begin to vibrate
True
What is the vibration of the vocal folds a result of?
Air being pushed through as the vocal folds continuously alternate between coming together (closing) and pushing apart (opening)
What is another word for the vibration pattern of the vocal folds that produces sound?
Phonation
How is the diverse range of sound qualities of the human voice accomplished?
Modulation of the vibration pattern of the vocal folds
The primary elements involved in vocal fold/voice modulations include how many cartilages and how many muscles?
3 Cartilages
5 Muscles
What are the 3 cartilages involved in voice modulation?
Thyroid cartilage
Arytenoid cartilage
Cricoid cartilage
Which is the largest cartilage of the larynx: thyroid, arytenoid, or cricoid?
Thyroid
Which type of cartilage is formed by 2 plates that join at the front of the throat (Adam’s apple)?
Thyroid cartilage
The _____ (anterior/posterior) end of the vocal folds attach to the _____ (inside/outside) of the thyroid cartilage
The anterior ends attach to the inside of the thyroid cartilage
What type of cartilages consist of a pair of small pyramid shaped cartilages that sit at the posterior edge of the thyroid cartilage?
Arytenoid cartilages
The arytenoid cartilages sit on top of what cartilage?
The cricoid cartilage
The vocal folds stretch between which two cartilages?
Thyroid and Arytenoid
Which voice modulation cartilage is shaped like a signet ring, and which way does the “wide” side face?
Cricoid cartilage - the wide side is at the back, and the narrow side is at the front
Which type of cartilage forms a ring, and is the lowest of the 3 types of cartilages involved in voice modulations?
Cricoid cartilage
The thyroid and arytenoid cartilages attach and form joints where?
On the back of the cricoid
Which joint allows the arytenoids to rotate, rock, and slide in a wide range of directions, and plays an important role in allowing for changes in the position of the vocal folds?
The cricoarytenoid joint
What does the cricothyroid joint allow for?
The up and down tilting of the thyroid cartilage - this plays a role in allowing for stretching of the vocal folds
What are the 5 primary intrinsic laryngeal muscles?
Posterior cricoarytenoid (PCA) muscle Lateral cricoarytenoid (LCA) muscle Interarytenoid (IA) muscle Cricothyroid (CT) muscle Thyroarytenoid (TA) muscle)
Which muscle opens the vocal folds (abduction)? What are its points of attachment?
PCA (Posterior Cricoarytenoid) Muscle
Originates on posterior of cricoid cartilage
Inserts on muscular process of arytenoid cartilage
-> rotates arytenoids outwards
Which muscles close the vocal folds (adduction)? What are their points of attachment?
LCA (Lateral Cricoarytenoid) Muscle
- Originates on lateral border of cricoid cartilage
- Inserts on muscular process of arytenoid cartilage
- > rotates arytenoids inwards and closes the vocal folds
IA (Interarytenoid) Muscle
- posterior surface of the arytenoids
- > pulls them together, thus pulling the vocal folds together
Which muscles are responsible for tensing and lengthening the vocal folds? What are their points of attachment?
CT (Cricothyroid) Muscle
- originates on the lateral surface of the cricoid cartilage
- inserts on the lower edge of the thyroid cartilage
- > pulls the thyroid cartilage forwards and downwards, thereby tensing and lengthening the vocal folds and raising the pitch
TA (Thyroarytenoid) Muscle
- originates on the vocal process of the arytenoid cartilage
- inserts on the angle of the thyroid
- (forms the main mass of the true vocal folds)
- > can stiffen and tense the vocal folds (can change vocal pitch and quality)
Explain the Myoelastic-Aerodynamic Theory of Phonation
Myo = muscle Elastic = tissue elasticity Aerodynamic = air pressure and flow
- widely accepted model of phonation
- states that, to produce phonation:
1) vocal folds adducted by continuously contracting LCA and IA (process called medial compression)
2) subglottal pressure builds up to ~3-5 cmH2O
3) pressure forces vocal folds apart
4) rapid opening of vocal folds causes rapid flow of air through opening
5) rapid flow produces negative air pressure between vocal folds, pulling them back together (Bernoulli effect)
6) vocal folds also pulled back together by elastic recoil of vocal fold tissues and continuous closing muscle contractions
7) once vocal folds are closed, cycle repeats, again and again
The process of negative air pressure, produced by the rapid flow of air through the vocal folds, pulling the vocal folds back together is know as the _____ Effect
Bernoulli
What is medial compression?
The continuous contraction of the closing muscles (LCA and IA) to bring the vocal folds together (adduction)
The vocal fold tissues are made up of how many layers?
5
What are the 5 tissue layers of the vocal folds?
Cover: Epithelium and Superficial Layer of the Lamina Propria
Transition: Intermediate Layer of the Lamina Propria and Deep Layer of the Lamina Propria
Body: Thyroarytenoid or Vocalis Muscle
What does the Cover Body Model refer to?
The stiffness of the cover layer and the body layer being able to be adjusted somewhat independently by contracting different muscles (ie. CT versus TA), which allows for a complex variety of voice qualities to be produced
True or False: Complex layering causes the vocal folds to vibrate in simple, predictable patterns
False - it causes the vocal folds to vibrate in a complex pattern (both vertical and longitudinal waves)
Explain what is meant when we say that there are vertical and longitudinal phase differences in the motion of the vocal folds?
During vocal fold vibration, there is a time lag between the opening and closing of:
- the inferior and superior portions of the folds (=vertical phase difference), and
- the anterior and posterior portions of the folds (=longitudinal phase difference)
The folds open from bottom to top and from posterior to anterior, and close from bottom to top and from anterior to posterior
What is a glottogram used for?
Measurement of the vocal fold opening and closing
What is the glottis?
The opening between the vocal folds
What are 3 visual methods for assessing the vocal folds?
High Speed Cinematography
Video Stroboscopy
Electroglottography (EGG)
How does High Speed Cinematography work?
- laryngoscope placed at back of the throat to view the vocal folds
- high speed film (4000 frames/sec) allows for 20-40 pics across each cycle of vocal fold vibration
- distance between vocal folds or area of vocal fold opening can be measured
Which visual method for vocal fold assessment takes pictures of the vocal folds in synchrony with a flashing light, taking only one picture of each cycle of vibration?
Video Stroboscopy
-if the flashing frequency is slightly slower than the fold vibration frequency, the result is a slow motion movie of the vibration cycle
What information can be obtained through video stroboscopy?
Distance between vocal folds
Area of glottis
Vocal fold movement patterns
What does EGG stand for?
Electroglottography
How does electroglottography work?
- 2 electrodes placed on either side of neck (on plates of thyroid)
- resistance and flow of electricity across the larynx/glottis changes as folds open and close
- electrical resistance changes shown as continuous waveform (reflect glottal opening)
What type of information can be obtained from an EGG?
Ratio of open/closing time
Closed phase duration
Slope of closing phase
True or False: Voice disorders are often associated with abnormal EGG measures
True