Transcript Laryngeal Anatomy and Physiology

Phonation
and
Laryngeal
Anatomy and Physiology
Nothing is ever said on the stage
without a reason. There are no
exceptions.
Charles Waxberg
The original use of the larynx was to keep us alive through
breakfast. Its main function is stop solids and liquids from entering
the trachea and choking us to death. Its secondary functions are to
bear down, phonation and speech. The larynx of humans and
great apes in infancy is higher in the neck so that they can breathe
and suckle at the same time. In humans it descends before the
age of two.
What the Larynx is for
• To stop food/liquid from entering the lungs
• To Bear Down
– While Expelling
• Defecation
• Childbirth
– While Lifting
• PHONATION
What is phonation?
• Laryngeal generation of
voice
Composition of the Larynx
• Composed of cartilage:
– Cricoid Cartilage – Greek Name meaning ‘ring
like’
– Thyroid Cartilage – Greek Name meaning
‘Sheild like’
– A pair of Arytenoids
– Epiglottis
Laryngeal Anatomy
anatomy.uams.edu/anatomyhtml/atlas_html/rsa3p2.html
1. Hyoid bone
2. Thyroid cartilage
3. Cricoid cartilage
4. Tracheal cartilages
www.bartleby.com/107/i
llus952.html
Larynx
www.ling.yale.edu:16080/ling120/Larynx/Larynx_side.gif
Cricoid
anatomy.uams.edu/.../atlas_html/rsa3p6.html
1.
Anterior arch
2.
Posterior
lamina
3.
Articular facet
Thyroid Cartilage
/www.yorku.ca/earmstro/journey/images/thyroid.gif
ARYTENOIDS
homepages.wmich.edu/~gunderwo/intro_voice.htm
1. Thyroid prominence
2. Cricothyroid ligament
3. Arytenoid cartilage
4. Corniculate cartilage
5. Vocal ligament
6. Vestibular fold
7. Cricoid cartilage
8. Articular facet for inferior
cornu of thyroid cartilage
anatomy.uams.edu/anatomyhtml/graphics/rsa3p8.gif
1.
Epiglottis
2.
Arytenoid cartilage
3.
Corniculate cartilage
4.
Aryepiglottic fold
anatomy.uams.edu/anatomyhtml/graphics/rsa3p10.gif
The thyroid rests superiorly on the cricoid and attaches posterior-laterally at the
cricoid’s inferior articulator facets. This attachment (the cricothyroid joint)
hinges the cricoid and thyroid allowing their anterior sides to adduct, changing
vocal fold length.
Movement
The arytenoid cartilages, two pyramid shaped cartilages rest on the cricoid
at the cricoarytenoid joints and move in two distinct ways:
1.) To pivot (rocking) the posterior ends of the arytenoids away from
each other, adducting the anterior ends or the reverse so the anterior ends
abduct, and…
2.) Sliding the arytenoids on an anterior-posterior path.
Since the vocal folds are attached to the anterior ends of these cartilages (at
the vocal process) any movement in them will change the folds’ shape,
tension and relationship to each other thereby affecting phonation.
people.umass.edu/jkingstn/ling414/figure%202.19%20arytenoid%20movement%20f05.jpg
Composition of the Larynx
(Con’t)
• Composed of Muscle:
– Extrinsic Laryngeal Muscles
– Intrinsic Laryngeal Muscles
Extrinsic Muscle
TWO Groups of Extrinsic Muscles:
• Suprahyoids – Attach to points above the Hyoid
(Jaw, Skull and Tongue) when they contract they
raise or elevate the Larynx eg Swallowing
• Infrahyoids – Attach to points below the Hyoid
(one connects to the thyroid, however the others
connect to the sternum and the scapula) when they
contract they lower or depress the Larynx
www.sloan-studios.com/pm/teachingtools.htm
Intrinsic Muscles
•
•
•
•
Adductors – vocal folds are together
Abductors – vocal folds apart
Tensors - Stiffen
Relaxors - Relax
Adductors
• Lateral Cricoarytenoids
• Interarytenoids
–Transverse Arytenoids
–Oblique Arytenoids
A
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t
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r
s
artemis.austincollege.edu/acad/music/wcrannell/vocalped/images/larynx1.gif
A
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artemis.austincollege.edu/acad/music/wcrannell/vocalped/images/larynx1.gif
137.222.110.150/calnet/H+N/image/deep%20muscles%20of%20larynx-lateral%20view.jpg
Abductors
• Posterior Cricoarytenoids
Vocal Folds
• Muscle
–External Thyroarytenoids – inserts into
the muscular process on the Arytenoids and the Thyroid notch (shorten
and adduct)
–Internal Thyroarytenoids – inserts into the
vocal process on the Arytenoids and the Thyroid Notch (shortens and
stiffens), act antagonistically to the Cricothyroids
• Membrane
137.222.110.150/calnet/H+N/image/deep%20muscles%20of%20larynx-lateral%20view.jpg
Membranes
• False Vocal Folds – Ventricular folds
• Laryngeal Ventricle
• Conus Elasticus (interconnects the thyroid, cricoid and arytenoids
cartilages)
• Lamina propria (mucosal cover of the vocalis
muscle) – can vibrate independently of the vocalis muscle
• Vocal Ligament – the thread like collagenous
fibers of the deep layer of the lamina propria
Relaxors and Tensors
• External Thyroarytenoid – Relaxor,
shortens and adducts
• Internal Thyroarytenoid – Tensor, shortens
and stiffens
• Cricothyroid Muscles – Tensor, lengthens
and stiffens
Pitch is determined by Relaxors and Tensors
www.kolumbus.fi/msts/larynx/larynx.htm
Fundamental Frequency
Phonation is made up of a fundamental
frequency or Fo (the number of times the folds
open and close per second-CPS) and harmonic
multiples of the Fo (two times the Fo, three
times, four times etc.) that fall in intensity
(volume) in an inverse relationship as the
harmonics rise in frequency or as the pitch
rises the volume falls.
Fundamental Frequency
10
9
8
7
6
5
4
INTENSITY
(VOLUME)
3
2
1
100
FREQUENCY
(PITCH)
200
300
400
500
600
700
800
900 1000
Pitch
• Fundamental frequency (average: baby 500Hz, children 250400Hz men 125Hz women 200Hz) is primarily affected by
applying more or less longitudinal tension
to the VF using:
• Cricothyroids
• Tension in the vocalis muscle
OR
• Adjustments in vertical tension – depressing or elevating
the Larynx via suprahyiod and infrahyoid muscles
Vocal Fold Tension, Elasticity
and Movement
•
•
•
•
•
Thicker or thinner
Shorter or longer
Open or close
Intermediate positions
Stiff or elastic
Movement:
Bronx Cheer or Raspberry– “the sound is that or air escaping in rapid bursts, not
the sound of the lips moving” – Borden and Harris. Aerodynamic forces acting
on the elastic body of the lips
ADMET – Aero Dynamic MyoElastic Theory
Glottal vibration is the result or refers to
interaction between aero-dynamic forces and
vocal fold muscular action.
• Sub-Glottal Pressure
• Bernoulli Effect – set vocal folds into vibration due to the elasticity
of the folds (elastic recoil – the force which restores any elastic body back to
its resting place)
• Muscular Force – Muscles act to bring the folds together so
they can vibrate, and muscles regulate their thickness and tension to
alter fundamental frequency. Folds are FULLY or PARTIALLY
ADDUCTED for phonation
Bernoulli Effect
• An increase in velocity results in a drop in
the pressure exerted by the molecules of
moving gas or liquid, the pressure drops
being perpendicular the direction of the
flow
Schematic showing the Bernoulli Effect. The arrows indicate movement of pressure. As the air
moves through a narrowing, inside pressure drops and outside pressure increases pulling the sides
inward.
Glottal Cycle
• Vertical Phase Difference – vocal folds open
at the bottom first. As top part opens bottom
part closes. Wave like motion
www.phon.ox.ac.uk/~jcoleman/phonation.htm
Chest (Modal Register)
•
•
•
•
Low fundamental frequency
Vocalis muscle activity
Folds are thick and short
Low stiffness
Falsetto Register
•
•
•
•
•
Longer and thinner folds
Stiff folds
Small amplitude of vibration
Incomplete closure of the folds
Shutter like appearance – Vibrate more like strings
Vocal Onset
• How we bring the folds together:
–
–
–
–
Attack
Breathy
Vocal Fry
Partial adduction – Whispering or falsetto
register
(Note: Folds come together FULLY but without
force for Modal register)
Pitch
• Lies in the stiffness of the folds resulting
from lengthening and contraction of the
thyroarytenoids, especially the vocalis
portion