Laryngeal Anatomy and Phonation

Flashcards covering key vocabulary terms related to laryngeal anatomy, vocal fold function, phonation theories, and related physiological processes from the lecture.

Shared Membrane in Larynx

A continuous lining connecting the epiglottis, vocal folds, and subglottal area, enabling them to move as one.

Intrinsic Vent Membranes

Connect each cartilage within the laryngeal structure together, making it continuous.

Ligaments in Larynx

Connective tissues that attach structures, thicker than membranes, helping with movement and stability.

Hyothyroid Ligament

Connects the inner surface of the thyroid cartilage to the hyoid bone.

Cricothyroid Ligament

Connects the thyroid cartilage to the cricoid cartilage.

Cricotracheal Ligament

Connects the cricoid cartilage to the trachea.

Aryepiglottic Fold

Extends bilaterally from the arytenoid cartilages to the epiglottis; contains cuneiform and canniculate cartilages and mucous glands.

Cuneiform and Canniculate Cartilages

Embedded within the aryepiglottic fold to provide pliancy for movement and prevent collapse during inspiration or being sucked in during swallowing.

Glottis

The space between the true vocal folds, at the level of the vocal folds.

Supraglottic

Refers to the laryngeal cavity region located above the glottis.

Subglottic

Refers to the laryngeal cavity region located below the glottis.

Ventricular (False) Vocal Folds

Anatomically sit slightly superior and lateral to the true vocal folds, important for preventing foreign particles from entering the airway and protecting the true vocal folds during swallowing.

Commissure (Anterior)

The common area where the true vocal folds (and also false vocal folds) come together and attach at a point on the thyroid cartilage.

Epithelium (True Vocal Folds)

The superficialmost, thin protective covering layer of the true vocal folds, acting as a barrier.

Lamina Propria

The layer of the true vocal folds located beneath the epithelium, consisting of three sub-layers: superficial, intermediate, and deep.

Superficial Layer of Lamina Propria

Loose connective tissue within the true vocal fold, also known as Renke's space, allowing free movement.

Renke's Space

The superficial layer of the lamina propria, composed of loose connective tissue, where fluid can accumulate (e.g., Renke's edema).

Intermediate Layer of Lamina Propria

Denser and more elastic fiber tissue within the true vocal fold, running parallel, allowing stretching.

Deep Layer of Lamina Propria

Composed of collagen (protein), which is denser than the intermediate layer, providing structure to the true vocal fold.

Thyroarytenoid Muscle (Vocalis Muscle)

The deepest and densest layer of the true vocal folds, one of the five paired intrinsic laryngeal muscles.

Layers of True Vocal Folds (Density)

Five distinct layers that increase in density from superficial to deep, enabling vibration due to the difference in physical properties.

Cover-Transition-Body Model

A biomechanical model grouping the five layers of the true vocal folds into three zones: Cover (epithelium + superficial lamina propria), Transition (intermediate + deep lamina propria), and Body (thyroarytenoid muscle).

Adduction (Vocal Folds)

The closed position of the true vocal folds, where they come together.

Abduction (Vocal Folds)

The open position of the true vocal folds, where they are apart.

Whispering

A glottal shape involving pressing the vocal folds together without full adduction, causing stress on the anterior portion and not recommended due to potential harm.

Cricothyroid Muscle

An intrinsic laryngeal muscle responsible for tilting the thyroid cartilage, which elongates, tenses, or condenses the true vocal folds, changing pitch.

Lateral Cricoarytenoid Muscle

An intrinsic laryngeal muscle responsible for adduction (closing) of the true vocal folds.

Interarytenoid Muscle

An intrinsic laryngeal muscle that assists in adduction (closing) of the true vocal folds.

Posterior Cricoarytenoid Muscle

An intrinsic laryngeal muscle responsible for abduction (opening) of the true vocal folds.

Phonation

The production of sound through the vibration of the true vocal folds, which can occur hundreds of times per second.

Vocal Fold Vibration Rate (Averages)

Approximately 100 Hz for adult males (sex at birth), 200 Hz for adult females (sex at birth), and 300 Hz for children, varying based on individual physical characteristics.

Purposes of True Vocal Fold Closure (Adduction)

Occurs during swallowing (tight closure), coughing (slamming vocal folds together), and phonation (nearly adducted, vibrating).

Myoelastic Aerodynamic Theory

A model explaining vocal fold vibration as a cycle involving muscle contraction (myo), elastic recoil (elastic), and aerodynamic forces (air pressure buildup and flow) causing displacement and recoil.

Bernoulli Effect

The scientific principle underlying vocal fold aerodynamics, stating that as air velocity increases through a narrow space (like the glottis), the pressure decreases, causing the vocal folds to be drawn together.

Vocal Fold Vibration Cycle

A single sequence involving the vocal folds starting closed, being displaced inferior-to-superiorly by subglottal pressure, blowing open, and then recoiling back to a closed position due to elasticity and decreased pressure.

Opening vs. Closing Phase of Vibration

The opening phase of vocal fold vibration takes longer than the closing phase, which occurs more quickly due to elastic recoil.

Pitch Change Mechanism

Primarily achieved by altering the tension and length of the true vocal folds; lengthening them makes them more tense, stiffer, thinner, and increases vibratory rate (higher frequency, higher pitch).

Modal Register

The habitual or natural speaking voice frequency range, characterized by consistent waveform.

Pulse Register (Glottal Fry)

A lower pitch range characterized by vocal folds closer together, resulting in a shorter, often irregular time pattern of vibration.

Falsetto Register (Loft)

A higher pitch range characterized by vocal folds that are further apart and stretched to their limit, resulting in a very high vocal frequency.

Loudness Change Mechanism

Primarily achieved by increasing subglottal pressure, which leads to greater amplitude of vocal fold vibration and altering the shape of the glottal airflow.

Superior Thyroid Artery

A major arterial supply of the larynx, providing blood to the pharynx, larynx, upper esophagus, and thyroid gland.

Ascending Pharyngeal Artery

A major arterial supply of the larynx, providing blood to the lower pharynx and the larynx.

Recurrent Laryngeal Nerve (RLN)

A branch of the vagus nerve that provides motor control to all intrinsic laryngeal muscles EXCEPT the cricothyroid; notable for its path around the aorta, making it vulnerable to surgery.

Superior Laryngeal Nerve (SLN)

A branch of the vagus nerve with two branches: an internal (sensory) branch and an external (motor) branch, which provides motor control to the cricothyroid muscle.

Infancy Larynx Location

Located higher, around cervical spine C3 or C4, during infancy.

Puberty Larynx Changes

The larynx becomes more inferior, vocal folds grow in length, thyroid angle changes, and sex hormones cause pitch breaks or changes in voice.

Aging Larynx

Undergoes structural changes (muscle atrophy, edema, demyelination of laryngeal nerves) and acoustic changes, requiring differentiation between typical aging and pathology.

Laryngeal Reflexes

Involuntary, protective mechanisms (e.g., coughing, swallowing reflexes) that occur at the level of the larynx in response to stimuli.