Anatomy of Phonation Chapter 4

Two Phases of Adduction

1) adducted in open phase 2) adducted in closed phase When the vocal folds are adducted, pressure is built up, which makes the vocal folds open from bottom to top. The vocal folds are then in the open phase and air flows between them, then they start to close because they are elastic and want to return to the resting position.

Dysphagia

A swallowing impairment.

Vocal Fold Vibration

Abducted, adducted open phase, adducted closing, adduced closed phase, adducted opening, adducted open, abducted. The vocal folds come together, vibrate and produce a sound, then have to open again. They have to approximate to build pressure to burst open. When the arytenoids are touching, then is it adduction, The vocal folds will vibrate as they open and then close again during adduction.

Cricoid Cartilage

Above the trachea- sits on top of the trachea. Articulates with the thyroid cartilage and the arytenoids sit on top of the cricoid as well. The cricoid cartilage is the lowest cartilage of the larynx and looks like a signet ring. I is thinner in the front and thicker in the back. It has facets for the arytenoid and thyroid cartilages. and also has an arch, which is the smallest/ thinnest part, and there is also a lamina, which is the the flat part on the outside of the cricoid.

Lateral Cricoarytenoid

Adducts the vocal folds. Pulls the arytenoids laterally (to the side), rotating the vocal processes of the arytenoids, and approximating the vocal folds. When this muscle contracts and shortens, the arytenoids move toward the midline.

Intrinsic Muscles of the Larynx

Consist of the lateral cricoarytenoid, the interarytenoids (transverse and oblique) the posterior cricoarytenoid, the thyroarytenoid, and the cricothyroid. These muscles change the shape and configuration of the glottis, which is the opening of the vocal folds.

Laryngeal Cartilages

Consists of the epiglottis, thyroid, cricoid, arytenoids, corniculates, hyoid bone, trachea. The thyroid cartilage is the largest cartilage of the larynx, It means shield in Latin and looks like a shield. Larynx is above the trachea, in front of the esophagus, level of the C4-C6. The vertebrae are behind the trachea and larynx. The cricoid and thyroid are attached by stems and these stems pull the arytenoid. When tension increases, vibration is faster and pitch goes up. The oblique line of the thyroid protrudes from the cartilage and muscles attach to it. It conists of a notch and an angle. Where the cartilage comes together is the degree of the laryngeal prominence. The arytenoid cartilages are on top of the cricoid cartilages. Corniculates are on top of arytenoid cartilage.

Thyroarytenoid Muscles

Divided into two separate portions. The medial or middle portion is the thyrovocalis, and the lateral or side portion is the thyromuscularis. When the thyromuscularis contracts, the thyrovocalis relaxes, so they act opposite of each other.

Suprahyoid Muscles

First need to know that the temporal bone has a mastoid process and a styloid process, which are both protrusions. All attach to the hyoid and help to elevate the larynx. Consist of the: -- Stylohyoid- originates at the styloid process and attaches to the hyoid bone. Elevates. CN VII which is the facial nerve -- Mylohyoid- CN V Trigeminal nerve, 3 + 2 -- Geniohyoid- CN XII Genio means tongue -- Genioglossus- CN XII -- Hyoglossus- CN XII -- Inferior Pharyngeal Constrictor -- Diagastric anterior and posterior- CN V and VII Are inside the mandible

Cricothyroid Muscle Parts

Has two parts: 1) pars recta, which is the more erect, vertical muscle 2) pars oblique, which is the more angled and oblique muscle These muscles increase the length of the vocal folds, which increases their tension. When tension increases then the vocal folds vibrate faster per second.

Bernulli Effect

If air pressure/fluid is constant, there is an inverse relationship between flow and pressure. Flow is -, pressure is +. Pressure is -, flow is +. Air always flows from an area of positive pressure to an area of lower pressure. If airflow is reduced, then pressure is increased. If airflow is increased, then pressure is reduced. An example is rafting or traffic flow. The arrow indicates the air flow from the trachea and lungs.

Thyroid Cartilage

Looks like a shield. There is a superior cornu, an inferior cornu, an notch, a prominence, a lamina, an angle, and an oblique line. The superior cornu attaches to the hyoid bone, and the inferior cornu attaches to the cricoid cartilage. There is a triticial cartilage is on top of the thyroid and attaches to the superior cornu.

Laryngeal Degrees

Men's thyroid cartilage is at a 90 degree angle. Women's thyroid cartilage is at a lesser angle, about 120 degrees. Men's vocal folds are thicker and vibrate slower. They have more prominence.

Extrinsic Laryngeal Muscles Intro.

One point is inside of the larynx and one point is outside the larynx. The thyrohyoid muscle, for example. The thyroid is in the larynx and the hyoid is outside the larynx. The extrinsic muscles raise and lower the larynx and are important for swallowing.

Cycle of Vibration

Open or abducted arytenoids, then they are open adducted, then they are adducted closing, then they are adducted closed, then adducted opening, then adducted open. Then abducted. The vocal folds always stay closed during voicing. During adduction, we have an open and closed phase. Always closed during voicing and the air pressure from the lungs beneath them makes them vibrate. If the vocal folds are stretched, then they will vibrate faster and the pitch will increase. Air pressure blows vocal folds apart from beneath. Average females have a 200 cycles per second. The vocal folds are opening and closing in cycles per second. The average male has 120 cycles per second. This is why males have a lower voice.

Phonation

Phonation is voice. During breathing the vocal folds are abducted which means they are open or apart. Phonation occurs when the vocal folds adduct (come together) and vibrate. We make the vocal folds vibrate by closing them and building up pressure below the vocal folds until they separate. Adbuction means that the vocal folds are apart. Adduction means that the vocal folds are coming together and vibrating. There are 2 phases of adduction: open phase and closed phase. Open phase occurs when the arytenoid cartilages are still touching but the glottis is open. The opening and closing of the vocal folds produces voice. Body language conveys 60-70% of information and intonation is also important, somewhere between voice and body language.

The Structures of the Larynx

Pronounced "lair rinks." The larynx is the voice box. It has 3 paired and 3 unpaired cartilages. It is superior to the trachea and anterior to C4-C6. Breathing is abduction and then you get ready to speak, so there is adduction, then we speak, and the air flow vibrates the vocal folds. Lungs to trachea, trachea to larynx, larynx (vocal folds).

Movement of the Arytenoids

The arytenoids rock, glide, and rotate. They rock and glide back and forth and mostly rotate. They allow the vocal folds to open and close.

Arytenoid Cartilages

The corniculate cartilages are on top of the arytenoid cartilages. They are a pyramid shape, the apex being the top where the corniculates are, and they have a vocal process on the inside and a muscular process farther outward. Muscles attach to the muscular process. The arytenoids help to move the vocal folds and glides open and close.

Cricothyroid Muscle

The cricoid may tilt back, but the thyroid does tilt forward. This causes the vocal folds to elongate. This causes vibration to be faster and pitch is higher. Elongation means that there is an increase in tension and this causes a faster vibration, and a higher pitch.

Muscles of the Larynx

The hyoid elevates and the larynx follows. This is important for swallowing. It moves up when swallowing and helps to protect the airway. It moves up and under the tongue. Food goes over the tongue and into the esophagus.

Landmarks of the Larynx

The landmarks of the larynx include the tongue, the epiglottis, the vallecullae, the vocal folds, the ventricular or false vocal folds, the pyriform sinus which channels food and liquids, the aryepiglottic folds, and the esophagus. There is a reflex of the vocal folds that cause us to cough to keep food and water out of the vocal folds. Keep foreign objects from getting into the airway. The valleculae is on the left and the right and is the psace between the epiglottis and the tongue. It is like a valley. The epiglottis closes when we swallow and diverts food around the vocal folds into a channel-like structure called the pyriform sinus, which is a space between the throat and the thyroid cartilage. Acid reflux can cause vocal problems because acid gets onto the the vocal folds. There are 3 valves that close when we swallow to protect the airway. The esophagus is always closed unless we swallow or puke.

Posterior Cricoarytenoid Muscle

The lone/sole abductor. This muscle contracts and opens the vocal folds for respiration and during unvoiced sound productions. See SISTER example. Some sounds are voiced and some are unvoiced. The origin of the cricoarytenoid muscle is the posterior cricoid lamina, so the flat back part of the cricoid. The insertion is the muscular process of the arytenoids, which are on the sides of the arytenoids. Abductory movement occurs in two stages: first, there is the lateral rocking of the vocal processes- rocking side to side, and then sliding of the arytenoid facets. There is a rocking a sliding and contraction which causes the opening.

Posterior Cricoarytenoid

The only muscle that opens the vocal folds. Called the "lone abductor." Insertion is the muscular process of the arytenoids. Origin is the cricoid.

Vagus Nerve

The superior laryngeal branch innervates the cricothyroid muscle. The recurrent branch comes from the brain stem down around the aorta, then up to the larynx. Nerves exiting the brain stem are called the cranial nerves. The vagus nerve is cranial nerve X and is called the wanderer. The superior laryngeal branch sends messages to the cricothyroid muscle which changes pitch. The vocal folds are moved by the cricothyroid muscle movement. I damaged, then there are problems with voicing. The vagus nerve has a left and right side and innervates the larynx from both sides.

Movement of Thyroid and Cricoid

The thyroid tilts forward down on top of the cricoid cartilage and this elongates the vocal folds. The arytenoids are exposed. The cricoid tilts upward.

False Vocal Folds

The ventricular vocal folds are superior and lateral to the vocal folds.

Vocal Folds

The vocal folds consist of 5 layers of tissue. The first is the epithelial covering, which makes the vocal folds look white. Then there are the 3 lamina propria. There is the superficial layer, which is the topmost, the intermidiate layer, which is the middle, and a deep layer, which is the deepest/innermost layer. Then under all of this is the thyroarytenoid muscle. The vocal folds open from the bottom to top and closes bottom to top. The vocal folds move in a wave like motion called the mucosal wave. Muscles are the stiffest part of the vocal folds, and the superficial laminate is gelatin like. The intermediate layer is like rubber bands, and the deepest layer is like a cotton string.

Extrinsic Laryngeal Muscles

There are 2 locations for the extrinsic laryngeal muscles: 1) suprahyoid muscles- above the hyoid bone, act as laryngeal elevators 2) infrahyoid muscles- below the hyoid bone, act as laryngeal depressors

Interarytenoid Muscles

There are 2: 1) Oblique arytenoid muscle 2) Transverse arytenoid muscle They are adductors and close the glottis.

Viewing the Vocal Folds

There are the: 1) False vocal folds, which are superior and lateral to the true vocal folds. 2) Ventricular space/vestibule 3) Vocal folds The vocal folds look white due to the outer covering of epithelial tissues.

Hyoid Bone

There is the greater cornu, the lesser cornu, and the corpus or body of the hyoid. There are 10 points of muscle attachment. The hyoid is the only floating bone in the body. It is suspended. Lots of muscles attach to the hyoid.

Infrahyoid Muscles

These muscles are laryngeal depressors and help to lower the larynx. They are located below the hyoid and attach to the hyoid.

Vocal Fold Movement

Vocal folds touch along the medial margin. The air pressure needs to build up under the vocal folds- called subglottal pressure beneath the vocal folds in the subglottal atrium.