Transcript CD 508_Anatomy

CD 508
VOICE & VOICE DISORDERS
Chapter 2
Anatomy & the Normal Voice
Aspects of Normal Voice
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Loud enough to be heard
Hygienic voice production
Pleasing vocal quality
Flexible enough to express emotion
Represent speaker re age and gender
Respiration
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Problem: conflict between physiological
need and speaking-singing demands-->
misuse of mechanism
Lung Schematic
INHALATION: Rib cage wall
expands; diaphragm contracts &
descends; lung air pressure
lowers; outside air rushes in
Lateral View of Inspiration
EXPIRATION: Passive collapse
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Lung tissue elasticity
Gravity
Visceral recoil
Rib untorquing
Relaxation Pressure
Most efficient and
pleasing voice
quality is produced
at mid air-pressure
and lung-volume
levels
 Tx: use midrange of
air pressure and
lung volume
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 Focus
on respiration training is
unnecessary for many patients
with dysphonia
Active Components
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Key Problem: tendency to squeeze
the glottis closed in order to produce
power, rather than increase air pressure
and airflow by contracting abdominal
muscles
--> strain on vocal mechanism
Muscles of Respiration
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INSPIRATION
Diaphragm
External intercostals
Pectoralis major &
minor
Costal elevators
Serratus posterior
Neck accessories,
esp.sternocleidomastoid
EXPIRATION
 Abdominals
 Internal intercostals
 Posterior inferior
serratus
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Expiration
PASSIVE
 Expiration entirely
due to passive
collapse properties
of thorax
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ACTIVE
 Adds function of
expiratory muscles
to prolong expiration
beyond simple tidal
volume
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Lung Volume & Capacity
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Tidal Volume - amt air in typical respiratory cycle
Inspiratory Reserve Volume - volume that can
be inspired past tidal volume - AKA Complemental Air
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Expiratory Reserve Volume -
volume expired
past tidal volume - AKA Supplemental Air
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Residual Volume -
air remaining in lungs beyond
max. expiration
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Vital Capacity -
amt. that can be expired after
maximum inhalation
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Total Lung Capacity -
total volume of air held in
lungs following maximum inhalation
Larynx
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Biological roles of
larynx
• prevents foreign
bodies from entering
airway
• fixates thorax by
stopping airflow at
glottal level,
permitting heavy
lifting/weight
supporting feats
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Valving action
• fixed framework
(cartilage)
• able to open/close
valve via intrinsic
muscles of larynx
• external support
from extrinsic
muscles of larynx
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Effect of head
position on
Airway patency
Respiration - Phonation
Cricoid
Cricoid Cartilage
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Sits atop the tracheal rings
Shaped like a signet ring - or enlarged
tracheal ring - which would fit loosely
on your little finger
Forms base for larynx
Arytenoids sit atop posterior wall
2 pts of contact with thyroid at
cricothyroid joint
Thyroid &
Epiglottis
Cartilages
Thyroid Cartilage
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Largest laryngeal cartilage
Thyroid notch at superior point of
thyroid angles
U-shaped - posterior aspect is open
Cornu (horns) articulate with hyoid
Epiglottis
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Leaf-like cartilage arising from angle of
thyroid cartilage, just below notch
Also attached to root of tongue, forming
the valleculae
Serves to divert food around airway
during swallowing process
Arytenoid Cartilages
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Paired cartilages, shaped like a pyramid
Most important in larynx
Base is concave; sits atop posterior
cricoid wall
Vocal process projects toward thyroid
notch; vocal cords attach there
Muscular process is point of attachment
for muscles that open and close cords
Slide laterally, rotate, and tilt inward
Extrinsic Muscles of the Larynx
Elevators
 Stylohyoid
 Mylohyoid
 Geniohyoid
 Genioglossus
 Hyoglossus
 Inferior laryngeal
constrictor
 Digastricus
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Depressors
Sternothyroid
Sternohyoid
Omohyoid
Thyrohyoid
Other
 Cricopharyngeus
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Extrinsic Muscles elevate and depress the larynx
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Lift larynx during swallowing
Minimal vertical excursion during
normal speech
Some elevation during high notes - esp
from untrained singers --> stress on
mechanism
Tx focus on minimal excursion
Intrinsic Muscles of the Larynx
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Adductors
Lateral
cricoarytenoid
Transverse arytenoid
Oblique arytenoid
Abductor
Posterior
cricoarytenoid
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Tensors
Medial
thyroarytenoid
Cricothyroid
Relaxers
Lateral
thyroarytenoid
Posterior Cricoarytenoid
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Lone abductor muscle
Origin posterior surface of cricoid
Angles up to insert in muscular process
of arytenoid on same side
Rotates vocal process laterally
Innervated by recurrent laryngeal nerve
Lateral Cricoarytenoids
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Adductors
Functions as direct agonist to posterior
cricoarytenoid
Origin in upper border of cricoid arch
and inserts onto muscular process of
arytenoid on same side
Rotates muscle process forward and
causes vocal process to ‘toe in’ at
midline
Transverse Arytenoids
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Adductors & fold compressors
Not paired, per se
Origin in lateral margin of one arytenoid
and traverses the distance to the same
spot on the other
Approximate bodies of arytenoids
together
Innervated by recurrent laryngeal nerve
Oblique Arytenoids
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Adductors
Origin in muscular process of one
arytenoid; inserts on apex of the other
Fibers continue to lateral border of
epiglottis --> aryepiglottic folds
Active during swallow & bring vocal
cords closer together by approximating
apex
Thyroarytenoid Muscles
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Tensors
Form bulk of muscular portion of folds
• Vocalis - inner section
• External thyroarytenoid - outer section AKA
thyromuscularis
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Origin inner surface of thyroid; insert in
vocal process and lateral surface of
arytenoids
Shorten to lower pitch; also adduct
glottis by muscular tension and
elasticity
Conus Elasticus
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Tough white membrane covering vocal
folds
Gives vocal cords their shiny white
appearance
Cricothyroid Muscles
Tensors
 Origin in anteriorlateral arch of
cricoid; insert a)
near lower horn of
thyroid & b) lower
margin of lateral
thyroid wall
 Innervated by
superior laryngeal
nerve
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Increases distance
between thyroid and
arytenoid cartilages,
increasing pitch by
stretching folds
 Tense folds by
lengthening them
 Minor adducting
action
 Cords run obliquely
if SLN impaired
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Summary of Intrinsic Muscle Activity
ANATOMY REVIEW
Phonation Function
and the Mucosal Wave
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Mucus lubricates tissue and dissipates
heat, increasing potential vibration
During phonation the cover over the
vocal fold body slides and produces a
wave that moves or travels across the
superior surface, dissipating before
reaching cartilage
Any extra mass will alter normal wave
Myoelastic Dynamic
Theory of Phonation
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Intrinsic adductors approximate folds as
expiration begins
Subglottal air pressure increases
Airflow velocity increases and blows
folds apart
Static mass of folds and Bernoulli
suction effect bring them back together
Contraction time @ 15 msec
Pitch Mechanism
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Fundamental frequency - rate of
vibration cycles per second
• Men - 125-150 Hz
• Women - 225-190 Hz
• Children - 285-295 Hz
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Related to fold thickness, length, and
elasticity
Mean thickness/mass systematically
decreases as pitch increases
F0 & Pitch Ranges
Table 2.2 Text
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SOPRANO
 F0 - 256 Hz
 170-1040 Hz
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ALTO
 F0 - 200 Hz
 140-700 Hz
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TENOR
 F0 - 135 Hz
 95-550 Hz
BASS
 F0 - 100 Hz
 80-340 Hz
Register
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Defined - a series of adjacent tones on
a scale with similar perceptual features
and seem to be generated by the same
type of vibrations
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Modal - normal conversation
Pulse - glottal fry; low pitch/airflow/volume
Falsetto - high pitched (male)
Whistle - very high (female), above F6
Loudness Mechanism
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Sound pressure level governed by
pressure supplied to larynx by lungs
As intensity increases folds remain
closed for longer periods during cycle
Greater intensity is characterized by
greater excursion of vibrating folds
More difficult to increase volume at low
pitch levels
Quality Mechanisms
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Perkins (1983)
• Constriction, vertical and horizontal focus
• ‘Head tone’ vs ‘Chest tone”
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Efficiency best at higher end of vertical
placement
Related to supraglottal resonance,
originating at glottis
Resonance Mechanisms
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Size and shape of vocal tract
Degree of muscular tension
• High frequency best with high degree of
pharyngeal wall tension
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Closure patterns that separate oral and
nasal cavities
• site usually Passavant’s area, whether
velar, posterior or lateral wall movement
Anatomy Reference
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Seikel, A., King, D. & Drumwright, D.
(2000). Anatomy and Physiology for
Speech, Language, and Hearing (2nd
ed.). San Diego: Singular Publishing/
Thompson Learning.