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CD 508 VOICE & VOICE DISORDERS Chapter 2 Anatomy & the Normal Voice Aspects of Normal Voice 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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CD 508

VOICE & VOICE DISORDERS


Chapter 2

Anatomy & the Normal Voice


Aspects of Normal Voice

  • Loud enough to be heard

  • Hygienic voice production

  • Pleasing vocal quality

  • Flexible enough to express emotion

  • Represent speaker re age and gender


Respiration

  • 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

  • Lung tissue elasticity

  • Gravity

  • Visceral recoil

  • Rib untorquing


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

Relaxation Pressure


  • Focus on respiration training is unnecessary for many patients with dysphonia


Active Components

  • 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


INSPIRATION

Diaphragm

External intercostals

Pectoralis major & minor

Costal elevators

Serratus posterior

Neck accessories, esp.sternocleidomastoid

EXPIRATION

Abdominals

Internal intercostals

Posterior inferior serratus

Muscles of Respiration


PASSIVE

Expiration entirely due to passive collapse properties of thorax

ACTIVE

Adds function of expiratory muscles to prolong expiration beyond simple tidal volume

Expiration


Lung Volume & Capacity

  • Tidal Volume - amt air in typical respiratory cycle

  • Inspiratory Reserve Volume - volume that can be inspired past tidal volume - AKA Complemental Air

  • Expiratory Reserve Volume - volume expired past tidal volume - AKA Supplemental Air

  • Residual Volume - air remaining in lungs beyond max. expiration

  • Vital Capacity - amt. that can be expired after maximum inhalation

  • Total Lung Capacity - total volume of air held in lungs following maximum inhalation


Biological roles of larynx

prevents foreign bodies from entering airway

fixates thorax by stopping airflow at glottal level, permitting heavy lifting/weight supporting feats

Valving action

fixed framework (cartilage)

able to open/close valve via intrinsic muscles of larynx

external support from extrinsic muscles of larynx

Larynx


Effect of head position on Airway patency


Respiration - Phonation


Cricoid


Cricoid Cartilage

  • 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 &EpiglottisCartilages


Thyroid Cartilage

  • Largest laryngeal cartilage

  • Thyroid notch at superior point of thyroid angles

  • U-shaped - posterior aspect is open

  • Cornu (horns) articulate with hyoid


Epiglottis

  • 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

  • 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


Elevators

Stylohyoid

Mylohyoid

Geniohyoid

Genioglossus

Hyoglossus

Inferior laryngeal constrictor

Digastricus

Depressors

Sternothyroid

Sternohyoid

Omohyoid

Thyrohyoid

Other

Cricopharyngeus

Extrinsic Muscles of the Larynx


Extrinsic Muscles - elevate and depress the larynx

  • 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


Adductors

Lateral cricoarytenoid

Transverse arytenoid

Oblique arytenoid

Abductor

Posterior cricoarytenoid

Tensors

Medial thyroarytenoid

Cricothyroid

Relaxers

Lateral thyroarytenoid

Intrinsic Muscles of the Larynx


Posterior Cricoarytenoid

  • 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

  • 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

  • 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

  • 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

  • Tensors

  • Form bulk of muscular portion of folds

    • Vocalis - inner section

    • External thyroarytenoid - outer section AKA thyromuscularis

  • 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

  • Tough white membrane covering vocal folds

  • Gives vocal cords their shiny white appearance


Tensors

Origin in anterior-lateral arch of cricoid; insert a) near lower horn of thyroid & b) lower margin of lateral thyroid wall

Innervated by superior laryngeal nerve

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

Cricothyroid Muscles


Summary of Intrinsic Muscle Activity


ANATOMY REVIEW


Phonation Function and the Mucosal Wave

  • 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

  • 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

  • Fundamental frequency - rate of vibration cycles per second

    • Men - 125-150 Hz

    • Women - 225-190 Hz

    • Children - 285-295 Hz

  • Related to fold thickness, length, and elasticity

  • Mean thickness/mass systematically decreases as pitch increases


SOPRANO

F0 - 256 Hz

170-1040 Hz

ALTO

F0 - 200 Hz

140-700 Hz

TENOR

F0 - 135 Hz

95-550 Hz

BASS

F0 - 100 Hz

80-340 Hz

F0 & Pitch RangesTable 2.2 Text


Register

  • Defined - a series of adjacent tones on a scale with similar perceptual features and seem to be generated by the same type of vibrations

    • Modal - normal conversation

    • Pulse - glottal fry; low pitch/airflow/volume

    • Falsetto - high pitched (male)

    • Whistle - very high (female), above F6


Loudness Mechanism

  • 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

  • Perkins (1983)

    • Constriction, vertical and horizontal focus

    • ‘Head tone’ vs ‘Chest tone”

  • Efficiency best at higher end of vertical placement

  • Related to supraglottal resonance, originating at glottis


Resonance Mechanisms

  • Size and shape of vocal tract

  • Degree of muscular tension

    • High frequency best with high degree of pharyngeal wall tension

  • Closure patterns that separate oral and nasal cavities

    • site usually Passavant’s area, whether velar, posterior or lateral wall movement


Anatomy Reference

  • Seikel, A., King, D. & Drumwright, D. (2000). Anatomy and Physiology for Speech, Language, and Hearing (2nd ed.). San Diego: Singular Publishing/ Thompson Learning.


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