What is phonation?
the product of vibrating vocal folds (voicing)
Where does phonation occur?
within the larynx
What is the larynx?
a musculo-cartilaginous structure that houses 2 bands of tissue we call the vocal folds
Where is the larynx located?
the superior end (top) of the trachea
What are the biological functions of the larynx?
- stops intrusion of foreign matter (choking)
- seals the respiratory system (can hold breath for swimming, etc)
- helps to "fix thorax" when vocal folds are closed so you can lift, defecate, push during childbirth
What are the major unpaired cartilages?
What are the major paired cartilages?
What is included in the framework of the larynx?
- major cartilages (cricoid, thyroid, arytenoid, corniculate, cuneiform)
- hyoid bone
What are the characterisitcs of cricoid cartilage?
- located at the base of the larynx / top of the trachea
What are the landmarks on the cricoid?
- amterior portion is low, vocal folds pass over this point
- posterior portion is where arytenoids connect
- lateral surfaces have facets which connect to inferior horns of thyroid cartilage (cricothyroid joint, a diarthroidal joint, permitting rotation)
What are joints?
form the functional connections between bones and cartilages (bone to bone and cartilage to cartilage)
What are the 3 major types of joints?
- synarthroidal/fibrous/immobile (bones of the skull)
- amphiarthrodial/cartilaginous/limited mobility (between disks of vertebral column)
- diarthrodial/synovial/highly mobile (shoulder)
What are the characteristics of the thyroid cartilage?
- largest of laryngeal cartilages
What are the landmarks on the thyroid cartilage?
- 2 plates (thyroid laminae)
- joined together at the thyroid angle
- superior-most point of angle is thyroid notch (vocal folds attach to thyroid cartilage behind the notch)
- oblique line (muscles attach here)
- posterior part is open
- 2 sets of cornu (horns): inferior: project down to articulate with cricoid; superior: project up to articulate with hyoid bone
What are the characteristics of the arytenoid cartilages?
- located on cricoid
- on superior surface of each arytenoid is a corniculate cartilage
What are the landmarks on the arytenoid cartilages?
- vocal processes: project anteriorly toward thyroid notch (posterior portion of vocal folds attaches here)
- muscular processes: muscles that open and close vocal folds attach here
What are the characteristics of the epiglottis?
- a "leaflike structure"
- arises from inner surface of the angle of the thyroid cartilage, just below notch (connected by the thyroepiglottic ligament)
- the sides of the epiglottis join with arytenoid cartilages by the aryepiglottic folds
- attaches to the root of the tongue (valleculae are in this region- important landmark in swallowing)
- also attaches to hyoid bone (hyoepiglottic ligament)
What are the characteristics of the cuneiform cartilages?
- embedded in aryepiglottic folds (situated above and anterior to the corniculate cartilages)
- provide support for membranous laryngeal covering
What are the characteristics of the hyoid bone?
- not a bone of the larynx
- provides union between tongue and larynx
- unpaired and small
- only bone in body that is not attached to another bone
- is "U" shaped, open in posterior
- corpus is main part (6 muscles attach to this)
- has cornu (greater and lesser)- more muscles attach to these
What is the cricothyroid joint?
- synovial joint
- junction of cricoid cartilage and inferior cornu of thyroid
- cricoid and thyroid rotate and glide in relation to one another
- thyroid rocks down and front, and can glide forward and backward
- allows for changes in vocal pitch
What is the cricoarytenoid joint?
- synovial joint
- the articulation between cricoid and arytenoid cartilages
- rocking, gliding, and minimal rotation
- the rocking action pulls 2 processes toward each other, allowing vocal folds to approximate (make contact) and abduct
What is the ventricular fold?
false vocal folds
Which extrinsic ligaments attach hyoid or trachea to laryngeal cartilages?
- thyrohyoid membrane (or hyothyroid)- stretches from greater cornu of hyoid to lateral thyroid cartilage
- lateral thyrohyoid ligament- cornu thyroid to cornu hyoid
- median thyrohyoid ligament
- *together these 3 connect larynx and hyoid bone
- connects hyoid and epiglottis
- connects thyroid and epiglottis
- connect tongue and epiglottis
- overlay of mucous membranes on these ligaments produce "little valleys" or valleculae between the tongue and epiglottis
- extrinsic ligament
- how trachea attaches to larynx
What are intrinsic ligaments?
- connect the cartilages of the larynx
- provide support for larynx and vocal folds
- an "undergirding" layer of connective tissue running from arytenoids to epiglottis and thyroid cartilage
- forms the false vocal folds
- ridges that mark highest elevation of aryepiglottic muscles
- course between epiglottis and arytenoids
What are the 5 layers of tissue ihn the vocal folds?
- 1. squamous epithelium- glistening appearance
- lamina propria (next 3):
- 2. elastin fibers
- 3. another layer of elastin fibers
- 4. collagen fibers (prohibit extension)
- 5. thyrovocalis muscle (makes up bulk of vocal folds)
- *1 and 2 make up "mucosal lining"
- *layers 3 and 4 make up "vocal ligament"
- space between aryepiglottic folds and thyroid cartilage
- also involved in swallowing process
entry to the larynx from pharynx above
first cavity of the larynx (space between aditus and ventricular folds/false vocal folds)
middle space of larynx
space between true vocal folds
the act of bringing the vocal folds together for phonation
the process of drawing the vocal folds apart to terminate phonation
- lateral cricoarytenoid
- transverse arytenoid
- oblique arytenoids
- pars recta (the medial-most component) and pars oblique (lateral to the pars recta)
- degree of force that may be applied to the vocal folds at their point of contact
- increased medial compression results from increased force of adduction
- increased medial compression is vital element in vocal intensity changes
- degree of force when stretching the folds
- change in longitudinal tension is important in changing pitch
Which refers to the degree of force that may be applied to the vocal folds at their point of contact: medial compression or longitudinal tension?
- function: adducts vocal folds, increases medial compression
- origin: superior-lateral surface of the cricoid cartilage
- course: up and back
- insertion: muscular process of the arytenoids
- movement: motion rocks arytenoids inward and downward
- function: adducts vocal folds, increases medial compression; pulls arytenoids closer together
- origin: lateral margin of posterior arytenoids
- course: laterally
- insertion: lateral margin of posterior surface of opposite arytenoids
Oblique (Inter)Arytenoid Muscles
- function: promote adduction, enforce medial compression
- origin: posterior base of the muscular procceses
- course: obliquely up
- insertion: apex of the opposite arytenoids
- movement: pulls apex of opposite arytenoids medially, rocks vocal folds down and in
- *also helps to pull epiglottis to cover larynx during swallow
- function: abduct the vocal folds
- origin: posterior cricoid lamina
- course: up and out
- insertion: posterior aspect of the muscular process of arytenoids cartilage
- movement: pulls muscular process posteriorly, rocking arytenoid cartilage out on its axis
- 2 parts: pars recta and pars oblique
- origin: PR- anterior surface of the cricoid cartilage immediately beneath the arch. PO- cricoid cartilage, lateral to the pars recta
- course: PR- up and out. PO- obliquely up
- insertion: PR- lower surface of the thyroid lamina. PO- point of juncture between thyroid laminae and inferior horns
- function: tenses vocal folds; pulls thyroid down
Thyrovocalis (medial thyroarytenoid)
- function: tenses vocal folds
- origin: inner surface, thyroid cartilage near notch
- course: back
- insertion: lateral surface of the arytenoid vocal processes
Thyromuscularis (lateral thyroarytenoid)
- function: relaxes vocal folds because of arytenoid rotation, pulling the arytenoids toward the thyroid cartilage
- origin: inner surface of thyroid cartilage near the notch
- course: back
- insertion: muscular process and base of arytenoids cartilage
- ***innervation for all intrinsic muscles: vagus X
Extrinsic muscles that are considered elevators (hyoid and laryngeal elevators)
Hyoid and laryngeal depressors
Non-speech laryngeal functions
- through clearing
- abdominal fixation
Laryngeal functions for speech
3 major laryngeal adjustments
- sustained phonation
- bringing the vocal folds together (adducting), caused by muscle action
- initiates voicing
Simultaneous vocal attack
vocal folds reach the critical degree of adduction at the same time as respiratory support is enough to support phonation ("zany")
Breathy vocal attack
starting airflow from lungs before adducting the vocal folds ("harry")
- adduction of vocal folds occurs prior to airflow (as it does in a cough)
- usually occurs when a word begins with a stressed vowel ("okay")
- stopping phonation (requires that hwe abduct the vocal folds)
- we terminate phonation many times during running speech
we get sustained phonation by holding the vocal folds in place, and by the Bernoulli effect
given a constant volume flow of air or fluid, at a point of constriction, there will be a decrease in air pressure perpendicular to the flow, and an increase in velocity of the flow
Summary of vocal fold movement
- we adduct the vocal folds using muscles of adduction
- we then tense the vocal folds and allow the Bernoulli effect to produce vibration and sustained phonation (using muscles to tense)
- we abduct the vocal folds using muscles of abduction
- these steps occur many many times in connected speech, depending on if sounds are voiced/voiceless, etc
Cycle of vibration
moving from one point in the vibratory pattern to same point again (open, closed, open again)
Mode of vibration
the pattern of activity that the vocal folds undergo during one cycle of vibration
differences in the mode of vibration of the vocal folds
3 common registers
- modal register
- glottal fry
- pattern of phonation used in daily conversation
- 2 variations: pressed phonation and breathy phonation
- with this type of phonation, medial compression is greatly increased
- voice sounds more harsh
- this is also more abusive to the vocal folds
- vocal folds are inadequately approximated- excessive airflow between the vocal folds (will hear air escaping)
- inefficient, but not abusive
- a variation from modal register (also called pulse register)
- voice sounds crackly
- low in pitch and sounds rough
- another variation from modal register
- the vocal folds lengthen and become extremely thin
- the vocal folds make contact only briefly, as compared with modal phonation, and the degree of movement is reduced
- sounds "thin" and high pitched
- the psychological correlate of frequency (of vibration)
- as frequency increases, pitch increases
the frequency of vocal fold vibration that is optimal for a given individual considering a function of the mass and elasticity of the vocal folds
the frequency of vibration of vocal folds that is habitually used during speech
Average fundamental frequency
frequency of vibration of sustained phonation (such as in conversational speech or reading passages)
the range of fundamental frequency for an individual
How do we alter pitch?
- through tensing and stretching the vocal folds (higher pitch)
- relax and shorten vocal folds (lower pitch)
the physical measure of power or pressure ratios (the amount of pressure exerted by the sound wave
- psychological correlate of intensity
- independent of each other (you can increase intensity without increasing frequency)