Voice Disorders Exam 1

biological functions of larynx

• clamps airway in response to possible intrusion by foreign objects

• rapidly expels foreign matter away from opening of airway

• vocal folds permit a person to hold their breath

• produces phonation

structure of larynx

musculo-cartilaginous structure

located at the top of the last ring of the trachea

adjacent to cervical vertebrae 4-6

average length

• adult males - 44mm

• adult females - 36mm

hyoid bone

attachment point for many important muscles, membranes, and ligaments

suspended in the throat, does not articulate with another bone, nor make a joint with any other bone

union between the tongue and laryngeal structures

loosely articulates with the superior cornu of thyroid cartilage

epiglottis

leaflike cartilage

protective structure during swallowing

not involved in typical english speech

thyroid cartilage

largest laryngeal cartilage

superior and inferior horns (cornu)

articulates with cricoid cartilage at the inferior horns making a diarthrodial joint called the cricothyroid joint

• allows thyroid to rock forward and backward

superior horn connected to hyoid bone via ligaments

superior thyroid notch is space just above the angle of the thyroid cartilage and just below the hyoid bone (known as adams apple)

cricoid cartilage

ring-shaped cartilage below the thyroid cartilage

narrowest arch in the front, widens posteriorly into a tall lamina

superior surface of the lamina supports the arytenoids

ligaments attach cricoid to thyroid superiorly, and 1st tracheal ring inferiorly

numerous muscle attachments

arytenoids

parid cartilaginous, pyramidal-shaped structures that articulate with the lamina of the cricoid cartilage

ride on high backed upper surface of cricoid cartilage

articulation with cricoid cartilage allows wide range of movement

vocal process serves as the posterior attachment for vocal ligament/fold

muscular process attachment point for adductors/abductor muscles

corniculate cartilage

ride on superior surface of each arytenoid

landmark in the aryepiglottic folds

cuneiform cartilage

reside within the aryepiglottic folds

hyothyroid membrane

connects hyoid bone to thyroid cartilage and gives rise to the middle and lateral hyothyroid ligament

conus elasticus

connects cricoid, arytenoid, and thyroid cartilages

gives rise to middle cricothyroid ligament, lateral cricothyroid membranes, and vocal ligaments

quandrangular membrane

connects epiglottis, thyroid cartilage, arytenoid cartilages, and corinuclate cartilages

thickens at bottom to become ventricular ligament

cricothyroid joint

synovial joint (rotational joint)

cricoid and thryroid attached via anterior, lateral, and posterior ceratocricoid ligaments

two motions:

• rotating (primary motion)

• gliding

cricoarytenoid joints

synovial joint

cricoid and arytenoid are attached via anterior and posterior cricoarytenoid ligaments

two motions:

• rocking right and left (primary motion)

• gliding front and back

intrinsic laryngeal muscles

muscles that have both origin and insertion on laryngeal cartilages

makes fine adjustments to the vocal mechanism itself

innervation is by the vagus nerve (CN X)

major functions of intrinsic laryngeal muscles

• open vocal folds

• close vocal folds

• tense vocal folds

• relax vocal folds

adductors

close the vocal folds

• lateral cricoarytenoid (LCA) - rock arytenoid in and down

• innerarytenoids (IA)

  • transverse arytenoid - medial compression to close vocal folds

  • oblique arytenoid - medial compression

abductors

open the vocal folds

• posterior cricoarytenoid (PCA) - only abductor of VFs

tensors

cricothyroid (CT) - pars recta and pars oblique

thyrovocalis - medial muscle of VFs

relaxors

thyromuscularis - muscle mass lateral to thyrovocalis - muscular portion of VFs

auxillary musculature (not important for speech)

thyroepiglottic - dilates the laryngeal opening

aryepiglottic muscle - deflects epiglottis over airway opening to help protect the airway during swallowing

posterior cricoarytenoid

originates on the back surface of the cricoid cartilage and inserts into upper and back surfaces of muscular process of the arytenoid

contraction rocks arytenoid cartilage away from midline and may also slide it upward and backward (VF abduction)

activated every time you breath

lateral cricoarytenoid

originates from the upper rim of the cricoid cartilage and inserts on the muscular process and front of the arytenoid cartilage

contraction rocks the arytenoid cartilage towards the midline and may slide arytenoid forward and toward the side

adducts vocal process of arytenoid, medial compression for louder voice

transverse arytenoid

originates on the back surface of one arytenoid and inserts at the same location on the other arytenoid

contraction pulls arytenoid cartilages toward each ther

adducts arytenoids/VFs

oblique arytenoid

originates from the back and side surface and the muscular process of the arytenoid and inserts in the apex of the opposite arytenoid; some fibers extend upward to become aryepiglottic muscles

contraction pulls arytenoid cartilages toward each other in tipping action

adducts arytenoid, narrows posterior chink

cricothyroid

pars rectus and pars oblique

originates from the outer front and side of the anterior arch of the cricoid cartilage and inserts on the outer front and side of the lower border of the lamina and inferior cornu of the thyroid cartilage

contraction decreases the distance between the upper border of the cricoid cartilage and the lower border of the thyroid cartilage at the front

primarily a rocking movement; also a forward sliding movement effected through the pars oblique

adducts these cartilages causing the VFs to lengthen and increase tension

primary pitch controller

fine structures of the VF’s

5 layers of tissue

1. squamous epithelium

2. superficial lamina propria

3. intermediate lamina propria

4. deep lamina propria

5. thyroarytenoid muscle

squamous epithelium

most superficial protective layer - appears white during laryngoscopic exam

superficial lamina propria

elastin fibers which can be extensively stretched

intermediate lamina propria

elastin fibers for elasticity and strength

deep lamina propria

supportive layer comprised of collagen fibers

thyroarytenoid muscle

5th layer of the VF’s - make up the bulk of them

thyroarytenoid

originates from inside surface of thyroid cartilage and inserts on ipsilateral arytenoid cartilage

makes up bulk of vocal folds

contraction of longitudinal fibers reduces distance between thyroid and arytenoid cartilages to shorten the VFs and/or increases their internal tension

pulls arytenoids forward, shortens, and thickens folds

contraction of vertical fibers influences ventricular folds

extrinsic laryngeal muscles

• muscles that have one attachment on a nonlaryngeal structure

• elevate or depress the larynx

• important in swallowing

hyoid and laryngeal elevators

• digastricus

• stylohyoid

• mylohyoid

• geniohyoid

• genioglossus

• hyoglossus

• thyropharyngeus

hyoid and laryngeal depressors

• sternohyoid

• omohyoid

• sternothyroid

• thyrohyoid

sternothyroid

originates from the back surface of the top of the sternum and the first costal cartilage and inserts on the outer surface of the thyroid cartilage

contraction pulls the thyroid cartilage downward

thyroid

originates in the outer surface of the thyroid cartilage and inserts on lower end of the greater cornu of the hyoid bone

contraction decreases the distance between the thyroid cartilage and hyoid bone

sternohyoid

originates from the back surface of the top of the sternum and inner end of the clavicle and inserts on the lower edge of the body of the hyoid bone

contraction pulls downward on hyoid bone

omohyoid

posterior belly originates from the upper edge of the scapula and inserts on a tendon near the sternum

anterior belly originates from the same tendon near the sternum and inserts in the lower edge of the greater cornu of the hyoid bone

contraction pulls downward and backward on hyoid bone

inferior pharyngeal constrictor

originates from the median raphe on the back of the pharynx and inserts on the sides of the cricoid and thyroid cartilages

contraction moves the sidewall of the lower pharynx inward

digastric

anterior belly originates from inside the lower border of the mandible and inserts into a tendon

posterior belly originates from the mastoid process of the temporal bone and inserts into the same tendon

contraction pulls the hyoid bone upward and forward or upward and backward

stylohyoid

originates from the back and side surfaces of the styloid process of the temporal bone and inserts into hyoid bone

contraction pulls upward and backward on the hyoid bone

mylohyoid

originates along the inner surface of the body of the mandible and inserts into a tendinous midline raphe or the front surface of the hyoid bone

contraction pulls upward and forward on the hyoid bone

geniohyoid

originates from the inner surface of the front of the mandible to the front surface of the body of the hyoid bone (runs essentially parallel to the anterior belly of the digastric muscle)

contraction can pull upward and forward on the hyoid bone

genioglossus

originates from the inner surface of the mandible and inserts into the undersurface of the tongue body and the body of the hyoid bone

contraction can pull the hyoid bone upward and forward

hyoglossus

originates from the side of the tongue and inserts on the body of the cornu of the hyoid bone

contraction can pull up on the hyoid bone

laryngeal ventricles

sometimes called the false vocal folds

contain ventricular ligaments and sparse muscle fibers

depression between the ventricular and true vocal folds

contain mucous glands that secrete mucus to lubricate the VFs

laryngeal cavity

extends from bottom of cricoid cartilage to laryngeal abitus

upper region is bounded by the ventricular folds below and laryngeal aditus above

lower region is bounded by the bottom of the cricoid cartilage below and the VFs above

glottis

5 layers of tissue, deepest is muscle

space between the folds

most important laryngeal space for speech

defined by the variable sphincter that allows voicing

as air passes between the VFs they may be made to vibrate

male difference in laryngeal anatomy

• larger thyroid lamina

• more acute thyroid angle, giving prominence to the thyroid notch or “Adam’s apple”

• thicker VFs

• larger glottal space

presbylaryngis

the term used to refer to the changes associated with the aging larynx

the left recurrent branch

ascends along a groove between the esophagus and trachea entering into the larynx behind the thyroid and cricoid cartilages

often cut during surgery

innervates 5/6 intrinsic muscles of larynx

superior laryngeal nerve (SLN)

it divides into an internal and external brach

internal branch - sensory innervation to base of tongue and supraglottal mucus membranes

external branch - motor innervation to lower pharyngeal constrictor

non-speech laryngeal function

• coughing

  • forceful evacuation of respiratory passageway in response to irritant or foreign matter

• throat clearing

  • clears respiratory tract of mucus

• abdominal/thoracic fixation

  • impounds air in thorax to stabilize the torse

laryngeal function for speech

phonation (voicing) is the product of vibrating VFs

• VFs vibrate as air passes through them

• phonation is maintained by the bernoulli effect and tissue elasticity

myoelastic theory of voice production

myo - muscle contraction of the lateral cricoarytenoid and thyroarytenoid muscle which posture the VFs in a nearly adducted position

elastic - the elastic properties of the VFs that are capable of being stretched, compressed, and deformed and returning to their original shape or state

aerodynamic - a branch of fluid dynamic concerned with the properties of airflow such as airflow velocity, air pressure, density, etc.

vocal fold vibration

medial surfaces of the vocal folds separate at the bottom first and return to midline at the bottom first

attack

start of phonation - adducting the VFs to move them into the airstream

sustained phonation

VF held in a fixed position in the airstream - maintenance of laryngeal posture through tonic (sustained) contration of the musculature

termination

abduct the vocal fold

simultaneous vocal attack

adduction and onset of respiration at the same time

breathy vocal attack

start significant airflow before adducting the VFs

glottal attack

adduction of the VFs prior to the airflow - if hard may damage the vocal mechanism

phonation threshold pressure

the minimum pressure amount needed to sustain vocal fold vibration

influenced by: hydration level, vocal skill, vocal fatigue, sound intensity and vocal pitch

abduction

movement of VFs away from midline

adduction

movement of VFs toward midline

modal register

• first type of vocal register

• phonation used in daily conversation

• most important register for speech language pathologist

• VFs open and close from inferior to superior

• minumum driving force is 3-5 cm H20 for 5 second

glottal fry register

• second type of vocal register

• crackly voice quality

  • rough and low in pitch

  • may indicate respiratory illness

• vocalis is tense so vibrating margin is flaccid and thick

• VFs spend up to 90% of the time in approcimation

pressed modal phonation

medial compression is greatly increase

stronger, louder phonation with a harsh or strident quality

breathy modal phonation

inadequate VF approximation with excessive airflow between the VFs in closed phase

may be due to an organic condition

whisper

no voicing occurs

vocal folds are partially adducted and tense

falsetto register

• third and highest register of phonation

• vocal sounds higher than normal range

• VFs lengthen and become very thin

• requires increased VF tension

• VFs make brief contact

whistle register

not a mode of phonation but a product of turbulence on the edge of the VF

Vocal fold length change

can be mediated through cricothyroid joints

VFs lengthen with contracction of the cricothyroid muscles and shorten with contraction of thyroarytenoid muscles

facilitates pitch by changing VF thickness

shortening → lower pitch

lengthening → higher pitch

stiffness of vocal folds

major contributor are the longitudinal tension exerted by cricothyroid muscles and activation of the muscles within the VFs (thyroarytenoid muscles)

another way to effect pitch change

respiration

the exchange of gas between an organism and its environment

• inspiration is bringing oxygen into the body’s cells by breathing in

• expiration involves eliminating carbon dioxide from the body’s cells by breathing out

pulmonary apparatus

contains air

conducts air

exchanges gas

chest wall

comprised of:

• rib cage wall

• diaphragm

• abdominal wall

• abdominal content

alveolar pressure

pressure inside the lungs

pleural pressure

pressure inside the thorax, but outside the lungs (between plural membranes)

abdominal pressure

pressure inside abdominal cavity

transdiaphragmatic pressure

difference in pressure across diaphragm

passive force

comes from:

• the natural recoil of muscles, cartilage, ligaments, lung tissue

• surface tension of alveoli

• gravity

whether stretched or compressed, the breathing apparatus will recoil like a spring toward its resting lengths

the more the breathing apparatus is deformed from its resting level, the greater the passive recoil force it generates

the lungs and chest wall are subject to passive forces

active force

comes from actions of muscles on the chest wall

magnitude depends on:

• which muscles are active and in what patterns

• amount of air in the breathing apparatus

the chest wall components create active forces; pulmonary apparatus (lungs) do not

quiet breathing

active muscle contraction during inspiratory phase

passive forces during expiration

forced exhalation

active contraction of abdominal musculature

speech (passive/active forces)

inspiratory muscles continue to be active in order to slow the elastic recoil of the inflated thorax

toward end of utterances, expiratory muscles being to contract to maintain necessary pressure for speech

tidal volume

volume of air inhaled and exhaled during any single expiratory cycle

inspiratory reserve volume

quantity of air which can be inhaled beyond that inhaled in a tidal volume

expiratory reserve volume

quantity of air that can be forcibly exhaled following a quiet or passive exhalation

residual volume

quantity of air that remains in lungs and airways after maximum exhalation

speech breathing

simultaneous control of ventilation/gas exchange and loudness, pitch, and speech segmentation into syllables, words, phrases

two forms:

• extended steady utterance

• running speech activities

extended steady utterance

deepest inspiration possible and speaking until air supply is depleted

• sustained vowel

• series of repeated syllables of equal stress

• sung note

running speech

reading aloud, public speaking, conversational speaking

highly variable, due to variation in phonetic content, prosody, and voice

control of tidal breathing

automatic breathing or involuntary breathing is controlled by brainstem

• generate rhythmic pattern of breathing

• regulate oxygen and carbon dioxide levels in blood by adjusting respiration

efferent control of breathing

• exiting brain

• signals from brainstem travel via peripheral nerves to muscle

• signals from cortical areas - limbic areas, motor areas, somatosensory areas

afferent control of breathing

• arriving to brain

• important for control of breaking pattern

• chemoreceptors - work synergistically to simulate adjustments in breathing

• mechanoreceptors