- Made up of the recoil forces of the lungs and the chest wall. aka "recoil curve"

- Active Muscle Force = Passive Recoil Force (but in opposite directions)

- When speaking, muscles of exhalation activate because recoil is not enough

- When alveolar pressure is the same as outside pressure.

- 38% of total volume.

- resting lung volume is higher when speaking

ACTIVE muscle force.

Above resting level, we use inspiratory muscles, below is expiratory.

- a supportive structure for the root of the tongue

- superior attachment point for extrinsic laryngeal muscles

(good to know: tongue/chin approach hyoid from above and front, temporal muscles approach from above and behind)

- U-shaped Body/corpus

- Greater horns/cornu: articulate with superior horns of thyroid

- Lesser horns/cornu

- Thyroid

- Epiglottis

- Cricoid

- Arytenoid (2)

- Corniculate (2)

- Cuneiform (2)

- Laminae (2)

- Superior cornu (attached to greater horn of hyoid)

- Inferior cornu (articulate with cricoid)

- Thyroid notch

- Angle of thyroid (where the lamina meet)

- Laryngeal prominence (adam's apple)

- oblique line (surface of lamina, site of muscle attachment)

two parts: anterior arch, posterior quadrate lamina arch

- articulation of inferior horns of thyroid = rocking motion of cricothyroid

- PQL articulates with arytenoids and thyroid

Body

Apex - process that points vertically

Muscular Process

Vocal Process

"cap" the arytenoids

hornlike

leaflike stem (petiolus) originates from angle of thyroid

thin and flexible cartilage that gets broad superiorly

at broadest part it is attached to hyoid bone via a ligament attached to root of tongue

median glossoepiglottic fold

lateral glossoepiglottic folds

valleculae (pitlike depression between epiglottis and roof of tongue)

contributes very little to production of speech

mostly prevents food from entering the larynx during swallowing

can sort of change size and shape of laryngeal cavity

rocking motion of arytenoid cartilage produces:

- an upward and outward swinging motion of the vocal process during abduction

- inward and downward swinging motion during adduction

Extrinsic Laryngeal Membranes

Hyothyroid membrane

- larynx is suspended by this membrane

- continuous sheet connecting all of top of thyroid cartilage and entire body of hyoid bone (arch and greater cornu)

- in midline it's thicker and is called the middle hyothyroid ligament

- at ends (between superior cornu and great cornu) thicker; lateral hyothyroid ligament

- an unpaired, midline, elastic ligament extending from anterior surface of the epigottis to the upper body of the hyoid bone

- connects lower border of cricoid cartilage with the upper bornder of the first tracheal ring

Intrinsic Laryngeal Membranes and Ligaments

Conus Elasticus

- located in cavity below vocal folds

- continuous sheet of membrane that connects the thyroid, cricoid, and arytenoid cartilages (three biggest)

- extends from superior border of the cricoid cartilage to upper limits of true vocal folds

- medial cricothyroid ligament (cricoid to thyroid)

- lateral cricothyroid ligament (thinner than medial, cricoid to vocal ligaments)

- connects epiglottis with thyroid and arytenoids

- from lateral margins of the epiglottis and thyroid cartilage (near angle)

- attach to corniculate cartilages and medial surface of arytenoids

- at bottom, terminates as false vocal folds, aka ventricular ligaments

- at top, becomes aryepiglottic folds

- continuous lining of entire larynx

Interior of the Larynx

Aditus Laryngis

- triangular opening (wider in front than behind)

- shape depends on position of arytenoids

- entry way into the laryngal cavity from the pharynx

- restricted by aryepiglottic folds

- cavity above false vocal folds and below the aditus

- space between aryepigottic folds

- basically, the airway

- anterior (bounded by vocal ligament) is membraneous gottis

- posterior (bounded by arytenoids) is cartiliginous glottis

- below vestibule

- between false vocal folds and true vocal folds

- extends entire length of the vocal folds

Ventricular Folds

(False Vocal Folds)

- incapable of becoming tense

- space in between is called false glottis

- origin: near angle of thyroid cartilage (anterior)

- insertion: arytenoids (posterior)

- medial borders are free

- consists of bundle of muscle tissue (thyroarytenoid) and a vocal ligament (part of conus elasticus)

- anterior part vibrates more than posterior

Extrinsic Muscles

(one attachment to structure outside larynx)

- function: support and fixation of the larynx

Infrahyoid muscles

Sternothryoid

- origin: posterior surface of manubrium

- insertion: oblique line

- draws thyroid downward, so lowers pitch

- origin: oblique

- insertion: greater cornu

- function: decreases distance between thyroid and hyoid. depresses hyoid and elevates thyroid. FIXES the hyoid. AND opening upper esophageal sphincter.

- main muscle for influencing vocal folds; stretches them

- raises/lowers frequency

- above the ST and TH

- origin: posterior surface of the manubrium

- insertion: body of the hyoid

- function: fixes the hyoid, pulls it down (depressor), lowers pitch

- two bellies

- inferior belly: scapula to intermediate tendon

- superior belly: intermediate tendon to greater horn

- function: neck doesn't collapse during inspiration, prevents blood vessels from being compressed

Suprahyoid Muscles

Digastric

- has two bellies

- anterior: mandible to intermediate tendon

- posterior: mastoid process of temporal to intermediate tendon

- function: raises hyoid bone and depresses lower jaw

- origin: styloid process of temporal bone

- insertion: body of the hyoid

- function: hyoid goes up and backward

- origin:inferior mental spine of the mandible

- insertion: body of the hyoid

- function: pulls hyoid up and forward

origin: mylohyoid line of the mandible

insertion: median raphe (and body of hyoid)

function: elevates hyoid, floor of mouth, and tongue. important for SWALLOWING

Intrinsic Muscles

(produce speech)

(always act in pairs)

- main mass of vocal folds, adductor

vocalis: medial, flanks vocal ligament, vibrating mass, when it relaxes the folds are thinner for vibration

thyromuscularis: lateral, rotates the arytenoids together

Cricoarytenoids

Lateral Cricoarytenoid

- adductor

- rotates arytenoid cartilage to bring vocal processes towards the midline (medial compression)

- lateral arch of cricoid to muscular process of arytenoid

- origin: PQL of cricoid

- insertion: muscular process of arytenoid

- function: ABductor. ONLY ONE.

Interarytenoids

Oblique

- muscular process of one to apex of other

- form an X

- MEDIAL COMPRESSION; bring arytenoids together, closes posterior gap, allows for subglottal pressure, loudness, closes aditus (both IAs)

Interarytenoids

Transverse

- posterior surface to posterior surface

- adducts arytenoids

Cricothyroid

- actively tenses (elongates) vocal folds!!! most important muscle for pitch changes

- arch to inferior thyroid lamina

- rocking motion!

pars oblique: more lateral; arch to inferior cornu

pars rectus: more medial; arch to lamina

- from lamina of thyroid to epiglottis

- protects the airway and closes the aditus by pushing the epiglottis back

- apex of arytenoids to epiglottis

- protects airway and closes aditus by pushing epiglottis back

- keeps epiglottis closed

- important for phonetic reasons (creating consonants)

- GERD: genetic disorder (gastro esophageal reflux disease), where stomach acids come up through esophagus and can enter into larynx; do surgery on UES to reduce effects

Innervation

Superior Laryngeal Nerve

Internal - sensory, cough reflex, innervates epiglottis, larynx, mucous membrane. protects the airway

External - motor innervations for cricothyroid muscle ONLY. important for voice ff, pitch control

- Motor for all other laryngeal muscles (NOT cricothyroid)

- sensory fibers that innervate from trachea to lower larynx

- easily damaged during thyroid surgery

- can lead to vocal fold paralysis if severed

- rate of vibration of the vocal folds

- represented in Hertz

- same as pitch

- length: increase, decrease ff

- thickness: increase, decrease ff (CT muscle)

- mpu: increase, decrease ff (resistance to movement)

- tension: the more tension, the more rapid opening and closing of the vocal folds, increase in pitch

- stiffness: increase, increase ff (CT muscle)

- medial compression: increase, increase ff (LCA)

- subglottal pressure: transglottal difference affects loudness

- airflow

- Transglottal Pressure difference

- Glottal impedance (same thing as stiffness) Thyromuscularis

- Glottal: forces vocal folds apart, starts with vocal folds closed

- Breathy: starts with vocal folds open, leads to wastage of air

- Simultaneous: begins with adduction of the vocal folds and exhalation

- open time/closed time

- decreases when loudness increases

- abduction/adduction

- opening/closing

- increases when loudness increases

Sulcus

a cyst forms in a cavity then ruptures

- dilation of a blood vessel

- hemorhage within a polyp

- smoker's polyps

- swollen and red

- air pulse and sound source are triangular

- fourier analysis: any periodic sound can be described as having fundamental and harmonic frequencies (series of sine waves of different frequencies)

- type of resonating frequency; in the vocal tract

- helmhertz cavities (each have their own resonating frequency); we change the shape of these with articulators

- peaks at a certain frequency and then falls away from that frequency; filters out those frequencies so that we only hear the source; creates perception of singular vowel sound