Voice Disorders Flashcards
Laryngeal skeleton:
1 Bone – hyoid bone
Hyoid membrane
6 Cartilages: Thyroid -Thyroid notch Cricoid Epiglottis - unpaired Arytenoid (2) -Vocal process and muscular process Corniculate (2) Cuneform (2)
Laryngeal Cavities:
Vestibule
Laryngeal ventricle
Glottis
Vocal Folds
Made up of different layers
Outer layer = epithelium
Below the epithelium = lamina propria
- Superficial layer = Reinke’s space
- Intermediate layer – less flexible than Reinke’s space
- Deep layer – less flexible than the first two layers
Below the lamina propria = thyroarytenoid muscle
Cover-Body Model
Cover = epithelium and superior layer of the lamina propria
Loose and pliable; vibrates the most
Vocal ligament = intermediate and deep lamina propria layers
Stiffer
Body = thyroarytenoid muscle
Stiffest
Extrinsic Muscles of the Larynx
Extrinsic – connect to the hyoid bone and a structure outside of the larynx
Divided into suprahyoids and infrahyoids
Suprahyoids- attach above the hyoid bone; contraction elevates the larynx
Infrahyoids- attach below the hyoid bone; contractions depresses the larynx
Intrinsic Muscles of the Larynx
Intrinsic – either abduct or adduct the vocal folds
Abduct – contraction opens the vocal folds
Adduct – contraction closes the vocal folds
Intrinsic Muscles of the Larynx
Intrinsic – either abduct or adduct the vocal folds
Intrinsic muscles – adduction
- Lateral cricoarytenoids (insert into the muscular process)
- Interarytenoid – transverse and oblique
Intrinsic muscles – abduction
-Posterior cricoarytenoid
Tensors – control vocal pitch
-Cricothyroid – pars rectus and pars oblique
Ligaments of the Larynx
Thyroepiglottic ligament
Joints of the Larynx
Cricoarytenoid joints
- Adduction
- Abduction
Cricothyroid joints
- Downward tilt of the thyroid cartilage
- Upwards tilt cricoid cartilage
Laryngeal Innervation
Vagus (not Vegas) X
Divided into three main branches:
Pharyngeal nerve – motor information to some soft palate muscles
Superior laryngeal nerve
Internal – sensory information to larynx
External – motor information to the cricothyroid muscle
Recurrent laryngeal – motor information to all intrinsic muscles of the larynx except cricothyroid
- Right recurrent loops around subclavian artery
- Left recurrent loops around the arch of the aorta (heart) – cardiac problems could cause vocal fold paralysis
Myoelastic-Aerodynamic Theory:
Muscle force - Lateral cricoarytenoid and interarytenoid muscles contract
Tissue elasticity – vocal folds
Air pressures – subglottal pressures
Bernoulli Principle:
Air increases velocity (speed) and decreases in pressure when passing through a narrow channel
This draws the vocal folds medially
Positive air pressure opens the vocal folds and negative air pressure closes the vocal folds
One cycle of vocal fold vibration
Voice Production
Mucosal wave created from vocal fold movement
- Open from bottom to top
- Close from top to bottom
Voiced speech sounds – vocal folds come together and vibrate
Voiceless speech sounds and inhale – vocal folds are apart
Fundamental frequency – rate of vocal fold vibration -Measured in cycles per second/Hertz Children 250-300 Hz Adult females 190-250 Hz Adult males 180-250 Hz
Pitch & Loudness
Raise pitch:
Vocal folds lengthen, tighten, and increase tension
Lower pitch:
Vocal folds relax, increase mass, and decrease vibration
Increase loudness:
Vocal folds are held together tightly
Subglottal pressure builds, then forcefully blows apart vocal folds
Vocal folds close more forcefully
Infant Larynx
Positioned high in the neck
-Gradually lowers until ~ age 15-20
Smaller
Vocal folds are short
Complex vocal ligament layers emerge around age 3 years
Neurologically immature (coordination improves w/ maturation)