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CD 508. VOICE & VOICE DISORDERS. Chapter 2. Anatomy & the Normal Voice. Aspects of Normal Voice. Loud enough to be heard Hygienic voice production Pleasing vocal quality Flexible enough to express emotion Represent speaker re age and gender. Respiration.
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CD 508 VOICE & VOICE DISORDERS
Chapter 2 Anatomy & the Normal Voice
Aspects of Normal Voice • Loud enough to be heard • Hygienic voice production • Pleasing vocal quality • Flexible enough to express emotion • Represent speaker re age and gender
Respiration • Problem: conflict between physiological need and speaking-singing demands--> misuse of mechanism
INHALATION: Rib cage wall expands; diaphragm contracts & descends; lung air pressure lowers; outside air rushes in
EXPIRATION: Passive collapse • Lung tissue elasticity • Gravity • Visceral recoil • Rib untorquing
Most efficient and pleasing voice quality is produced at mid air-pressure and lung-volume levels Tx: use midrange of air pressure and lung volume Relaxation Pressure
Focus on respiration training is unnecessary for many patients with dysphonia
Active Components • Key Problem: tendency to squeeze the glottis closed in order to produce power, rather than increase air pressure and airflow by contracting abdominal muscles • --> strain on vocal mechanism
INSPIRATION Diaphragm External intercostals Pectoralis major & minor Costal elevators Serratus posterior Neck accessories, esp.sternocleidomastoid EXPIRATION Abdominals Internal intercostals Posterior inferior serratus Muscles of Respiration
PASSIVE Expiration entirely due to passive collapse properties of thorax ACTIVE Adds function of expiratory muscles to prolong expiration beyond simple tidal volume Expiration
Lung Volume & Capacity • Tidal Volume - amt air in typical respiratory cycle • Inspiratory Reserve Volume - volume that can be inspired past tidal volume - AKA Complemental Air • Expiratory Reserve Volume - volume expired past tidal volume - AKA Supplemental Air • Residual Volume - air remaining in lungs beyond max. expiration • Vital Capacity - amt. that can be expired after maximum inhalation • Total Lung Capacity - total volume of air held in lungs following maximum inhalation
Biological roles of larynx prevents foreign bodies from entering airway fixates thorax by stopping airflow at glottal level, permitting heavy lifting/weight supporting feats Valving action fixed framework (cartilage) able to open/close valve via intrinsic muscles of larynx external support from extrinsic muscles of larynx Larynx
Cricoid Cartilage • Sits atop the tracheal rings • Shaped like a signet ring - or enlarged tracheal ring - which would fit loosely on your little finger • Forms base for larynx • Arytenoids sit atop posterior wall • 2 pts of contact with thyroid at cricothyroid joint
Thyroid Cartilage • Largest laryngeal cartilage • Thyroid notch at superior point of thyroid angles • U-shaped - posterior aspect is open • Cornu (horns) articulate with hyoid
Epiglottis • Leaf-like cartilage arising from angle of thyroid cartilage, just below notch • Also attached to root of tongue, forming the valleculae • Serves to divert food around airway during swallowing process
Arytenoid Cartilages • Paired cartilages, shaped like a pyramid • Most important in larynx • Base is concave; sits atop posterior cricoid wall • Vocal process projects toward thyroid notch; vocal cords attach there • Muscular process is point of attachment for muscles that open and close cords • Slide laterally, rotate, and tilt inward
Elevators Stylohyoid Mylohyoid Geniohyoid Genioglossus Hyoglossus Inferior laryngeal constrictor Digastricus Depressors Sternothyroid Sternohyoid Omohyoid Thyrohyoid Other Cricopharyngeus Extrinsic Muscles of the Larynx
Extrinsic Muscles - elevate and depress the larynx • Lift larynx during swallowing • Minimal vertical excursion during normal speech • Some elevation during high notes - esp from untrained singers --> stress on mechanism • Tx focus on minimal excursion
Adductors Lateral cricoarytenoid Transverse arytenoid Oblique arytenoid Abductor Posterior cricoarytenoid Tensors Medial thyroarytenoid Cricothyroid Relaxers Lateral thyroarytenoid Intrinsic Muscles of the Larynx
Posterior Cricoarytenoid • Lone abductor muscle • Origin posterior surface of cricoid • Angles up to insert in muscular process of arytenoid on same side • Rotates vocal process laterally • Innervated by recurrent laryngeal nerve
Lateral Cricoarytenoids • Adductors • Functions as direct agonist to posterior cricoarytenoid • Origin in upper border of cricoid arch and inserts onto muscular process of arytenoid on same side • Rotates muscle process forward and causes vocal process to ‘toe in’ at midline
Transverse Arytenoids • Adductors & fold compressors • Not paired, per se • Origin in lateral margin of one arytenoid and traverses the distance to the same spot on the other • Approximate bodies of arytenoids together • Innervated by recurrent laryngeal nerve
Oblique Arytenoids • Adductors • Origin in muscular process of one arytenoid; inserts on apex of the other • Fibers continue to lateral border of epiglottis --> aryepiglottic folds • Active during swallow & bring vocal cords closer together by approximating apex