Phonation

Corniculate Cartilages

Elastic cartilage. Apexes of the arytenoids are capped by corniculate cartilages.

Genioglossus Muscle

Elevates hyoid and draws it forward. Extrinsic muscle of the tongue. Strap muscle - suprahyoid.

Thyromuscularis

External thyroarytenoid. Indirectly involved in vibration, contraction = shortening = adduction = primary relaxer.

Hyoglossus Muscle

Extrinsic tongue muscle extending from hyoid bone up into the back of the tongue lateral to the genioglossus to pull the dorsum down. Strap muscle - suprahyoid.

Cricoid Cartilage

Hyaline structure. Immediately atop trachea, forms bottom of the larynx. Signet ring like or hexagonal in shape.

Extrinsic Laryngeal Muscles

Hyoglossus muscle, genioglossus muscle, thyropharyngeus. Muscles with one attachment on laryngeal cartilage and the other on a nonlaryngeal structure; make major adjustments to larynx (elevating or depressing); work with tongue and many are important for swallowing.

Vestibule

Important for swallowing, food liquid in vestibule is not below the VF, called penetration not aspiration. Supraglottal region between the ventricular folds and the aditus.

Interaction of Thyroid and Cricoid

Important in modulation of pitch. Thyroid - allows rocking forward, then they rock the VFs lengthen. Thyroid rocks posteriorly - VFs shorten (tilt away from each other).

Glottal Fry

Most extreme in low pitch, VFs move slowly - closed phase longer than normal.

Falsetto (register)

Most extreme register in high pitch, VFs long thin and tense

Male and Female Pitch

1 year old - 400 Hz Females - 224 Hz Males - 125 Hz Protective reflex - sudden increase in sub glottal air pressure (punch in stomach) = pitch increase. Larynx rises - higher pitch, larynx lowers - lower pitch. Result of extrinsic laryngeal muscles.

Vocal Happenings - Cough

Both true and false folds slam together.

Laryngeal Cartilages

9 cartilages= 1 thyroid, 1 cricoid, 2 arytenoid, 1 epiglottis, 2 corniculate, 2 cuneiform. Either hyaline or elastic. Function is to support muscles.

Larynx

A cartilaginous midline neck structure, located between trachea inferiorly and hyoid bone superiorly.

Hyoid Bone

A single, horseshoe shaped floating bone (not attached to any other bone) suspended in the neck between the mandible and larynx. It is a point of attachment for swallowing and speech muscles.

Lateral cricoarytenoid muscles

Adductor muscles, close = adduction of vocal folds.

Transverse Arytenoid + Oblique Arytenoids

Adductors

Bernoulli Effect Phonation

Air from lungs going through glottis as its adducting - > VF will suck together, velocity of pressure - suction pressure b/n folds. VF sucked together - sub glottal pressure increased - sub glottal air pressure overcomes medial compression - VF will begin to vibrate.

Vocal Folds (Plicae Vocales)

Attached anteriorly. Long smooth bands of muscle tissue, lengthened and shortened, relaxed or tensed, abducted or adducted.

Attack Phase of Phonation

Attack Phase - vocal folds are adducted and begin to vibrate due to pressure from below, 3 types of attack: simultaneous, breathy, glottal.

Voice Disorder Qualities

Breathiness - VF do not approximate as they should, strength and surety of speech reduced. Harshness - VFs have excessive tension, associated with glottal attack, too low pitch, a periodic noise. Hoarseness - lower pitch/voice not as loud, comb of breathiness and harshness, laryngeal pathology, diplophonia.

Conus Elasticus

Broad continuous membrane. Top is narrower, superior = glottal. Lower portion of the elastic membrane. Cone shaped appearance. Covers entire inner wall of larynx. Connects thyroid, cricoid. and arytenoid cartilages. Covered with mucosa that can move independently from the glottal edge.

Intrinsic Laryngeal Membranes

Connect all cartilages of larynx. Interconnect the cartilages of larynx and helps direct their movement. Elastic membrane - continuous fibroelastic sheet that lines the larynx. Three parts: Conus elasticus, quadrangular membranes, mucous membranes

Thyropharyngeus

Constricts pharynx and elevates larynx.

Laryngeal Joint- Cricothyroid

Cricoid + thyroid cartilages. Jointed together at inferior horns of thyroid and lateral surface of cricoid cartilage. Pivot joint, diarthrodial joint. Allows for thyroid cartilage to rock forward and back elongating vocal folds. Important in pitch change.

Thyrohyoid

Depresses hyoid or elevates larynx.

Omohyoid Muscle

Depresses the hyoid. Strap muscle, infrahyoid.

Laryngeal Elevators

Digastric muscle, stylohyoid muscle, mylohyoid muscle, geniohyoid muscle. All assist in swallowing by moving the hyoid bone and tongue up and forward.

Stylohyoid Muscle

Draws hyoid bone up and backward. Inferior/slightly anterior attachment to the hyoid bone; superior/slightly posterior attachment to the styloid process; fibers run roughly parallel and deep to the posterior belly of the digastric muscle. Strap muscle - suprahyoid.

Sternothyroid Muscle

Draws thyroid downward. Strap muscles, omohyoid.

Vocal Ligament

Each fold contains 2 muscle bundles bound by vocal ligament forming medial portion of fold - thyrovocalis, thyromuscularis (make up thyroarytenoid muscle). Integral part of the mucosal cover of the vocalis muscle. Muscle and mucosal layer make up the vocal folds.

Major Laryngeal Membranes

False vocal folds - above the VF, indentations of membrane. Laryngeal ventricle - area between false folds and true folds. Conus elasticus - continuation of mucous membrane, glottal edges to cricoid cartilages. Connect all main laryngeal cartilages together.

Mylohyoid Muscle

Fan like, elevates hyoid bone, floor of mouth and tongue. If hyoid fixed, may depress mandible. Deep to digastric paired muscle that forms the floor of the mouth. Function: Depression of the mandible or the elevation of the hyoid bone and tongue. Strap muscle, suprahyoid.

Aryepiglottic Folds

Folds of mucous membranes, enclose ligamentous and muscle fibers. Extend from the side of the epiglottis to the apexes of the arytenoid cartilages. Form the entrance to the larynx.

Pre Phonation Phase - Medial Compression

Force with which VF brought together in midline, tighter VF hold together @ midline - changes vocal quality. Function of interarytenoid and lateral cricoarytenoids. Amount of air pressure needed to blow VF apart from below depends on medial compression

Pyriform Sinuses

Formed by space between aryepiglottic folds and arytenoid cartilages.

Hyoid Bone [image]

Greater horns (cornua, articulate with the superior horns of the thyroid cartilage), lesser horns (cornu), corpus (body)

Extrinsic Laryngeal Membranes

Group that connect the laryngeal cartilages to adjacent structures. 1. Hyothyroid membrane - connect hyoid with thyroid cartilage 2. Paired lateral hyothyroid ligaments 3. Hyoepiglottic ligament 4. Cricotracheal membrane

Pre Phonation Phase - Longitudinal Tension

How tightly folds are pulled in their length. Extensive stretching force of VFs, major tensor muscles responsible.

Increase Vocal Intensity - Loudness by

Increasing airflow with constant VF restriction. Increase VF resistance at constant air flow. Opening phase shorter and closed phase is longer for louder voice. Intensity is amp of fold movement - how far apart and how close/tight. Depend on increased sub glottal air pressure due to greater medial compression.

Methods of Investigation

Indirect laryngoscopy, stroboscopy, direct laryngoscopy by endoscopy, computerized tomography scan, magnetic resonance imaging.

Vocalis Muscle

Innermost layer of VF - thyroarytenoid muscle

Vocal Happenings - Phonation during Inspiration

Inspiratory stridor. A whistling sound when breathing (usually heard on inspiration)

Muscles of Vocal Folds

Internal thyroarytenoids (thyrovovalis), external thyroarytenoid (thyromuscularis), cricothyroid muscles, posterior cricoarytenoids, lateral cricoarytenoid muscles, transverse arytenoids, oblique arytenoids

Thyrovocalis

Internal thyroarytenoids. Responsible for vibration, contraction pulls on vocal process of arytenoids. Major tensor = closes = adduction.

Muscles of the Larynx

Intrinsic - all attachment confined to larynx, responsible for control of sound production. Extrinsic - one attachment to the laryngeal cartilage, primarily responsible for support and fixation. Laryngeal and hyoid elevators/depressors.

Laryngeal Ventricle

Large indentation in mucous membrane, between false folds above and true folds below. Extends almost full length of VF, bound laterally by external thyroarytenoid. Contains mucous glands for lubrication to larynx.

Thyroid Cartilage

Largest of the cartilages. Wing-like shape. Composed of the thyroid lamina, thyroid prominence, superior cornu, inferior cornu, oblique line. Hyaline.

Laryngeal Buzz

Laryngeal tone/buzz. The Bernoulli effect creates in this complex harmonic sound.

Epiglottis

Leaf shaped elastic cartilage. Very flexible, closes laryngeal vestibule during swallowing. Protects airway so foo goes over and down esophagus. Posterior to hyoid bone and root of tongue.

Loudness

Listener's perception to the amount of energy in a sound, intensity. Energy is known as sound pressure level spl, measured in dB. Muscles involved: adductors, tensors, expiratory muscles.

Vocal Happenings - Jitter/Shimmer

Little disturbances in frequency/pitch and sometimes loudness. Unintended and abnormal. Speaker is 'unsteady.'

Vocal Folds (Plicae Vocales)

Located at level of Adam's apple. Thyroarytenoid muscle and vocal ligament.

Vocal Folds

Located in the middle of the larynx and open and close to control the flow of air.

Lamina Propria

Mucosal cover of VF. Surrounds thyroarytenoid muscle and composed of 3 layers of collagen fibers. Deep - dense and stiff fibers like threads. Intermediate - elastic fibers similar to rubber bands. Superficial - gelatinous, fibers are sparse, thing and loose.

Attack Phase - Active Forces

Muscles in larynx to adduct and abduct the folds. Areodynamic/myoelastic theory of voice. Basis for human voice - combination of Bernoulli effect, tissue elasticity, muscle action.

Lateral Process of Arytenoids

Muscular process, point of attachment for muscle involving VF movement

Cricoid Cartilage (structure)

Narrow anterior - cricoid arch. Broad posterior cricoid lamina. Articular facets - place for attachment of the cricoarytenoids. Anterior notch.

Vocal Happenings - Whisper

Non-vocal sound production, not engaging VFs, can't get many words out.

Laryngeal Depressors

One attachment below the larynx. Sternohyoid muscle, omohyoid muscle, sternothyroid muscle, thyrohyoid.

VF Function

Open during normal breathing. VF vibration cycle - vocal fold adduction -> build up of sub-glottal air pressure -> VF blow apart releasing puff of air into vocal tract -> decrease of pressure beneath VF/tissue elasticity -> vocal folds snap back for next cycle.

VF Vibration - 3 Phases

Opening Phase - 50% Closing Phase - 35% Closed Phase - 15%

Arytenoid Cartilages

Paired structure, hyaline. Sit atop cricoid lamina (posterior structure)

Attack Phase - Tissue Elasticity

Passive forces - allow VF to come back together a little in a 'rest position', velocity of air increases again because folds come closer than wide apart.

Function of Larynx

Phonation, protection valve = keep objects out of airway and expel foreign objects.

Loudness and Pitch

Pitch affects whether loudness results from increasing air flow or increasing VF resistance. High pitch - glottal resistance is high, VF are more stiff. Loudness results from changes in air flow overcoming this resistance.

Mechanics of Voice Control

Pitch, loudness, quality, register

Cricoid Attachment

Posterior lamina separates into 2 depressions = ridge serves as a point of attachment for the muscle fibers of esophagus. Arch - small oval articular facets for articulation with the inferior horns of the thyroid.

Geniohyoid Muscle

Pull hyoid up and forward. Action - Depresses the mandible - Elevates the hyoid bone Strap muscle - suprahyoid

Sternohyoid Muscle

Pulls hyoid downward.

Digastric Muscle

Raises the hyoid bone or if hyoid fixed, depresses the lower jaw. Has muscle fibers at either end and a collagenous tendon in the middle intermediate tendon. Function: By contracting it can create a backward pull on the mandible. Strap muscle - suprahyoid.

Pitch - Fundamental Frequency Fo

Rate of opening and closing the VFs, physical correlate of perceived pitch. Higher Fo = higher pitch, lower Fo = lower pitch measured in Hz. Affected by size of larynx, VF mass, VF tension.

Bernoulli Effect

Reduction of air pressure with increases in air flow, as air rushes into opening created by fold movement, the air pressure is reduced between folds, folds are sucked back together. Constant airflow through a constriction - velocity will increase. How air moves.

Posterior cricoarytenoids

Rock and glide arytenoids apart. Abductor.

Hyoid Bone Attachment

Root of tongue attaches to corpus. Forms inferior attachment for majority of tongue musculature. Supper attachment for some extrinsic laryngeal muscles.

Vocal Registers

Series of tone with similar quality, 3 registers.

Vocal Happenings - Vibrato

Small/rapid pitch and intensity changes, mostly in singing - trill. Pathology - tremulo not in speakers control, or vibrato in speech.

Glottis

Space between the VFs Sub-glottal = structures below the glottis Supranational = structures above the glottis

Vocal Happenings - Hiccup

Sudden violent diaphragmatic and VF contraction

Thyroid Horns (Cornua)

Superior + inferior horns. Posterior margin of each laminae extend superior and inferior. Attachment of superior horns -> ligament to the hyoid. Attachment of inferior horns -> down from thyroid lamina to the cricoid cartilages.

False Vocal Folds (Ventricular Folds)

Superior to vocal folds, protrude into airway. Originate just below attachment of epiglottis, insert at the lateral edge of arytenoids. Passive. Thick. appear to be white. Hyperfunction - false volds vibrate [ventricular phonation]

Viewing VF

Tend to undulate in waves during phonation, like jelly being shaken.

To Control Fo

Tensor muscles - tighten and lengthen folds - vibrate more rapidly - cycle of vibration shorter - glottal area smaller - pitch goes up. Relaxer muscles - make folds shorter - pitch goes up

Intrinsic Laryngeal Muscles - Functions

Tensors= thyrovocalis, cricothyroid. Relaxers = thyromuscularis. Adductors = lateral crcioarytenoid, transverse arytenoid, oblique arytenoid. Abductors = posterior cricoarytenoid.

Aditus Laryngis

The entry to the larynx from the pharynx above. Formed by arytenoid and epiglottic cartilage.

Epithelium

Thin layer covering the mucosal tissue

Intrinsic Laryngeal Muscles - Groups

Thyroarytenoids - thyrovocalis (internal), thyromuscularis (external. Interarytenoids - transverse arytenoid, oblique arytenoid.

Thyroid Lamina

Thyroid prominence - Adams apple. Thyroid notch - forms anterior attachment of vocal folds.

Tensors

Thyrovocalis + cricothyroid muscles. Lengthen vocal folds.

Modal Register

Used for everyday conversation. Normal pattern of vibration.

Pre Phonation Phase

VF begin to proximate, VF vibrate before totally adducted. Pressure builds up - VF vibrate - exhalation - VF are together and pressure needed to blow them apart.

Laryngeal Innervation

Vagus Nerve (cranial nerve X) - recurrent laryngeal nerve. Brain stem to left aorta to larynx, innervates intrinsic muscles of larynx. Superior laryngeal nerve - innervates the cricothyroid muscle. Accessory nerve - cranial nerve XI Hypoglossal nerve - cranial nerve XII, innervates extrinsic muscles of larynx.

Quadrangular Membranes

Ventricular ligaments -inferior margin. Aryepiglottic folds - superior margin. Upper part, epiglottis - thyroid - goes back to arytenoid cartilages.

Medial Process of Arytenoids

Vocal ligament of VF attaches

VF Multilayered Structure

Vocalis Muscle - Lamina Propria - Vocal Ligament - Epithelium

Glottal Tone

Voice (not speech) through pharyngeal, oral, nasal cavities

Cuneiform Cartilages

Wedge shaped rods of elastic cartilages. Appear as elevations or swelling when larynx viewed from above. Lend support to the aryepiglottic fold, imbedded within the aryepiglottic folds.

Laryngeal Joint - Cricoarytenoid

Where the cricoid cartilage and arytenoid cartilages touch. Rocking and gliding action. Rocking - up and out swinging motion of the vocal process during abduction. Down and in during adduction. Diarthrodial joint.