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Bone
Cartilage
Ligament
Membrane
Muscle
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Innervation
Extrinsic muscles
Intrinsic muscles
How the vocal folds
vibrate
• Initiating vibration
• Pitch
• Registers
• Vagus (CN X)
• Superior laryngeal nerve:
• Cricothyroid (CT)
• Recurrent laryngeal nerve:
• Thyroarytenoid (TA)
• Posterior Cricoarytenoid (PCA)
• Lateral Cricoarytenoids (LCA)
• Interarytenoids (IA)
Blumenfeld, H., 2002, Neuroanatomy through Clinical Cases, Sinauer, Inc.
• Many extrinsic laryngeal
muscles
• Thyrohyoid
•Elevates larynx
• Sternothyroid
•Depresses larynx
Hixon, T.J., et al. (2008). Preclinical Speech Science: Anatomy Physiology Acoustics Perception. Pg. 112.
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Innervation
Extrinsic muscles
Intrinsic muscles
How the vocal folds
vibrate
• Initiating vibration
• Pitch
• Registers
• Bulk of the vocal folds
• Contractions can result in:
• Shortening the vocal folds
• Pulling thyroid and arytenoid
cartilages toward each other
• Increasing the tension of the vocal
folds
• Isometric (contracting and not
changing length)
• Shorten: decreases pitch
• Increase tension: increases pitch
Hixon, T.J., et al. (2008). Preclinical Speech Science: Anatomy Physiology Acoustics Perception. Pg. 98.
• When it contracts, it helps to lengthen the vocal folds
• It elevates the cricoid arch, and depresses the thyroid lamina
(shortens the space between the cricoid and the thyroid)
• This can help to increase pitch
Hixon, T.J., et al. (2008). Preclinical Speech Science: Anatomy Physiology Acoustics Perception. Pg. 97.
• CT active and TA passive = increase pitch
• Increase length
• Increase stiffness
• TA active and CT passive = decrease pitch
• Decrease length
• Decrease stiffness
• TA and CT contract simultaneously = increase pitch
• Increase stiffness
• Work in opposition
• PCA:
• Rocks arytenoids away
from midline
• Opens the vocal folds
• LCA:
• Rocks arytenoids toward
midline
• Closes the vocal folds
Hixon, T.J., et al. (2008). Preclinical Speech Science: Anatomy Physiology Acoustics Perception. Pg. 100.
• PCA:
• Rocks arytenoids away
from midline
• ABducts the vocal folds
• LCA:
• Rocks arytenoids toward
midline
• ADducts the vocal folds
Hixon, T.J., et al. (2008). Preclinical Speech Science: Anatomy Physiology Acoustics Perception. Pg. 107.
• Transverse:
• Pulls arytenoids toward
each other
• ADducts the vocal folds
• Oblique:
• Tips one arytenoid (apex)
toward the other (body)
• ADducts the vocal folds
Hixon, T.J., et al. (2008). Preclinical Speech Science: Anatomy Physiology Acoustics Perception. Pg. 101.
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Innervation
Extrinsic muscles
Intrinsic muscles
How the vocal folds
vibrate
• Initiating vibration
• Pitch
• Registers
• Many theories of vocal fold vibration
• Myo-elastic aerodynamic theory of vocal fold vibration
• Nonuniform tissue movement: Multimass models
• Van den Berg, 1958
• Based on Bernoulli equation:
P + ½ pv2 = constant
• P = pressure
• p = fluid density
• v = velocity
• Please use this formula- I believe the formula in your
book is incorrect.
• This equation states that as pressure increases, velocity
decreases (assuming density is constant)
Based on Titze, I.R. (2000). Principles of Voice Production.
• Van den Berg, 1958
• Based on Bernoulli equation:
P + ½ pv2 = constant
• Basics of this theory:
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When the vocal folds are closed, pressure builds in the subglottal region
When the pressure is high enough, it forces the vocal folds open
The vocal folds continue to open further as air rushes out
Once they reach a maximum opening, the elasticity in the vocal folds pulls
them together
• The cycle repeats
• Other theories in between,
but this is the most recent
• Explains self-sustained
oscillation: as the vocal folds
continue to oscillate (vibrate),
they are able to sustain the
same velocity and width of
excursion
Titze, I.R. (2000). Principles of Voice Production.
• Upper and lower parts of
the vocal folds do not
move as one
• The lower part of the
vocal folds moves first,
followed by the upper
part
• Convergent: lower further
apart than upper
• Divergent: upper further
apart than lower
Titze, I.R. (2000). Principles of Voice Production.
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Innervation
Extrinsic muscles
Intrinsic muscles
How the vocal folds
vibrate
• Initiating vibration
• Pitch
• Registers
• Phonation threshold pressure (PTP): smallest subglottal
pressure needed to start self-sustained oscillation
• For low frequency phonation, PTP is around 3-4 cm H20
• Average pitch:
• Women: 220 Hz
• Men: 130 Hz
• Registers
• Chest (Low pitches)
• Middle/Mixed (Middle
pitches)
• Head/Falsetto (High
pitches)
Zemlin, pg 166.